SR
Uploaded byShelby Roller
PPT, PDF1,996 views

Federico Capasso: Photonics as Design

Federico Capasso is a designer of new materials using nanotechnology. Some of his most important work includes developing quantum cascade lasers and flat optics. Quantum cascade lasers emit laser light by passing current through nanometer-thick layers, allowing the laser wavelength to be tailored. This enabled numerous applications in chemical sensing, medical imaging, and more. Flat optics uses metasurfaces to refract light instead of lenses, opening opportunities to replace lenses in many applications. Capasso's work has advanced fields like photonics, materials science, and biomedical technologies.

Embed presentation

Download to read offline
Photonics as Design Federico Capasso John A. Paulson School of Engineering and Applied Sciences Harvard University http://www.seas.harvard.edu/ capasso  I am designer of new materials with man-made electronic and optical properties, built using nanotechnology  Here I concentrate on the most important results of my group: quantum cascade lasers and flat optics
• Light-technologies provide solutions to global challenges • Light sciences are a cross-cutting discipline in the 21st century Ban Ki Moon The International Year of Light and Light-based Technologies 2015 UNESCO Opening Ceremony
Light-technologies provide solutions to global challenges Environmental monitoring Networks & Lighting (LED) Atom-like systems for nanoscale MRI, in vivo functional imaging Flat Optics : Replacing lenses in a wide range of applications Energy & Lighting Environment Healthcare Communications Security Culture and Art
The interferometer detects changes in the difference between its two arms as small as 1/ten thousand of the proton size (one ten millionth of a billion of a meter) due to the stretching and compression of space-time caused by the catastrophic union of two black holes 1.3 billion years ago Far Reaching Impact of Optical Technology in Fundamental Science: Direct Detection of Gravitational Waves Cosmic Union of Two Black Holes: Extreme Physics and Extreme Optical Technology "There are more things in heaven and earth, Horatio, than are dreamt of in your philosophy” W. Shakespeare, Hamlet (1.5.167-8) Predicted by Einstein over 100 years ago!
Chemistry Beryllium Aluminum Silicate, lauePhysics Biology Material Science The Nanometer: where sciences converge Why now? 11 nm = 1 billionth of a meter
Beyond atoms and molecules: nanoscale building blocks DNA 2 nm Carbon nanotube ~1-2 nm 5 nm Nanocrystal, aka quantum dot BIOLOGY CHEMISTRY PHYSICS GATHERED FROM DIFFERENT SCIENCES (P. Alivisatos) Metamaterial
Molecular Beam Epitaxy (MBE) : Spray Painting Atoms ! Can deposit 1 atomic layer! • A very precisely defined mixture of atoms to give EXACTLY the desired material composition! • Artificial Man-made materials by Design: enormous potential for science and technology Invented by Alfred Y. Cho; Bell Laboratories 1968-69 We collaborated for 25 years COMMERCIAL MBE SYSTEM 1 nm = 1 billionth of a meter
Birth of the Quantum Cascade Laser Jan. 14, 1994 , Bell Labs J. Faist, F. Capasso, D. L. Sivco, C. Sirtori, A. L. Hutchinson, A. Y. Cho, Science 264, 553 (1994). Charles H. Townes, Nobel Laureate for the Laser: “This represents a remarkable combination of excellent solid-state and laser physics with new solid-state technology. It opens the door to very important new laser possibilities, ones I hope will be pursued and achieved”
New class of laser materials designed bottom up using Quantum Mechanics J. Faist, F. Capasso, D.L. Sivco, C. Sirtori, A.L. Hutchinson, A.Y. Cho, Science 264, 553, (1994) Layer Thickness determines the wavelength !
Laser wavelength can be changed by varying thickness of layers to match almost any molecular fingerprint : detection of chemicals in tiny concentrations Quantum Cascade Laser: Passing current through nanometer thick layers leads to emission of laser light
The cascade Molecular Beam Epitaxy 45nm "MINIGAP" Zone de transport Zone d ’émission 3 2 1 e- e- "MINIBANDE" CASCADE scheme : Recycling of carriers; N periods = N photons per carrier Injector active region
Spectral coverage of lasers 100 200 300 400 500 600 700 800 900 1,000 3,000 30,000 Ultraviolet Visible Near-infrared Mid-infrared terahertz HeNe 633 nm Ruby 694 nm Nd:YAG 1064 nm XeF 351 nm XeCl 308 nm KrF 248 nm ArF 193 nm Ti:sapphire 700-1000 nm Ar-ion 364-514 nm Diode Dye CO2 10.6 µm Quantum Cascade Laser have filled this gap, Enabling countless scientific and technological applicationns Er:YAG 2.94 µm
Molecular Fingerprint Region Microwaves THz Mid-IR Near -IR UV Mid-Infrared: Molecular Fingerprint Region Mid-Infrared: Every molecule has a unique absorption fingerprint → chemical sensing with high sensitivity and selectivity Major Applications are: Sensors and spectroscopy • Industrial process control • Quality control of chemical processes • Detection of explosives and hazardous gases • Compliance testing of tablet, capsules, powders • Medical: breath analysis, tissue imaging • Environment / Energy: pollution monitoring, • atmospheric chemistry
15 Quantum Cascade Laser Products Cover The Entire Mid-Infrared Peak Pulsed Laser Performance M2095-PX QCL: D0102 M2068-PX QCL: HD0364 M2080-PX QCL: D0470 M2049-PX QCL: D0519 M2042-PX QCL: J0017 M2058-PX QCL: D0454 M2052-P QCL: KD0370 M2100-PX QCL: D0398 M2130-PX QCL: D0820 M2038-P QCL: J0162 M2035-P QCL: J0092 M2040-P QCL: D0571 • Largest product portfolio • CW and pulsed • Fastest tuning • Highest fidelity • Best technical support
1E-5 1E-6 1E-7 1E-8 1E-9 1E-10 1E-11 1E-12 PowerSpectralDensity(W/2cm- 1) Wavelength (µm) Uncooled Enables High-speed, high-resolution acquisition Liquids Solids Tissues …as well as semiconductors, powders, and slurries… The QCL Advantage Great potential as a source in FTIR spectrometers: e. g. spectroscopy of proteins in a water environment
The QCL enables a broad range of chemical sensing applications Life Sciences Environmental Sciences Materials Science 1800 1700 1600 1500 1200 1100 1000 9001400 1300 Absorption Wavenumber (cm-1) Proteins β-sheet Proteins α-helical RNA DNA Lipids Lipids Collagen Glycogen
Enabled by the QCL: Pharmaceutical Drug Development Keles et al. Org. Process Res. Dev. (2017) Petibois et al, Chem. Sci., 2017 Real-time, Small-scale Drug Synthesis Pre-clinical Mouse Brain Chemical Mapping Drug Quality Control Courtesy: Tim Day, Daylight Solutions DRS
Enabled by the QCL: Life Sciences Protein Folding Dynamics Faist et al. Analytical Chemistry (2018) Lendl et al. Analytical Chemistry (2018) Protein Secondary Structure Blood Biomarker Discovery Hughes et al. Sci. Reports (2016) Cancer Free Brain Cancer Breast Cancer Lung Cancer Skin Cancer Courtesy: Tim Day, Daylight Solutions DRS
Powered by the QCL: Aircraft Protection Pollock, et al. The Infrared and Electro-Optical Systems Handbook, Vol. 7, Countermeasure Systems (1993) Small SWaP enables installation on lightweight rotary-wing and commercial aircraft Simplistic architectures facilitate military ruggedized systems for harsh environments Inherent reliability provides significant lifecycle cost reduction compared to legacy systems Courtesy: Tim Day, Daylight Solutions DRS High Power: > 5 Watt CW at λ ~ 4.5 µm 2016 US Military qualifies QCL for aircraft protection
QC Laser Multipass cavity Detector Spectroscopy and Chemical Sensing with Lasers • Fundamental vibration modes of molecules are in the Mid-IR – Chemically and isotopically sensitive N O
Real-time Exhaled Human NH3 Breath Measurements Successful testing of a 2nd generation breath ammonia monitor installed in a clinical environment.(Johns Hopkins, Baltimore, MD and St. Luke’s Hospital, Bethlehem, PA) 14:24:00 14:24:20 14:24:40 14:25:00 14:25:20 0 50 100 150 200 250 300 350 400 NH3 concentration[ppb] Time [HH:MM:SS] Breath data from NH3 Rice sensor Max NH3 concentration is: 351 ppb 0 1000 2000 3000 4000 0 2 4 6 8 10 12 0 50 100 150 200 250 CO2 concentration[%] AirwayPressure[mbar] Point [-] Pressure CO2 NH3 NH3 concnetration[ppb] Airway pressure (black), CO2 (red), and NH3 (blue) profiles of a single breath exhalation lasting 40sec. Minimum detectable concentration of NH3 is: ~ 6 ppbv at 967.35 cm-1 (1σ; 1 s time resolution)
Pole-to-Pole Observations of Carbon Cycle and Greenhouse Gases using Quantum Cascade Laser Spectrometers Gulf Stream V Aircraft QCLs for CO2, CO, CH4, N2O LATITUDE AND ALTITUDE HIGH PRECISION PROFILES OF TRACERS FOR GLOBAL CIRCULATION MODELS PRECISION: (concentration) CO2 30 ppb (340 ppm) CO 0.2 ppb (80 ppb) CH4 0.8 ppb (1800 ppb) N2O 0.1 ppb (320 ppb) Prof. STEVEN WOFSY, HAVARD e ALTITUDE PROFILES CO CH4 N2O CO2 New information about the emissions of greenhouse gases into the atmosphere: critical for predicting climate change
ATMOSPHERIC (Troposphere & Stratosphere) TRACE GAS MEASUREMENTS WITH QCLs TRACE GAS cm-1 std dev 1s ppb 76 m path LoD ppb 100 s NH3 967 0.2 0.06 C2H4 960 1 0.5 O3 1050 1.5 0.6 CH4 1270 1 0.4 N2O 1270 0.4 0.2 H2O2 1267 3 1 SO2 1370 1 0.5 NO2 1600 0.2 0.1 HONO 1700 0.6 0.3 HNO3 1723 0.6 0.3 HCHO 1765 0.3 0.15 HCOOH 1765 0.3 0.15 NO 1900 0.6 0.3 OCS 2071 0.06 0.03 CO 2190 0.4 0.2 N2O 2240 0.2 0.1 13CO2/ 12CO2 2311 0.5 ‰ 0.1 ‰ LIGHTWEIGHT MULTIPASS CELL (76m) LASER 1 CH4 1270.785 N2O 1271.078 CO 2179.772 LASER 2 ABSORPTION SPECTRUM DUAL-LASER INSTRUMENT DESIGN
• The measurements resolve the vertical and horizontal structure of the atmosphere: first to provide a high-resolution section of the atmosphere— the QCL spectrometers are uniquely capable of making this kind of observation. • The patterns provide new information about the locations and strengths of emissions of greenhouse gases to the atmosphere.
27 NASA Altair UAV Drone for detection of chemical in impervious regions Jim Anderson, Harvard
Transition from quantum cascade lasers to flat optics  Was facilitated by a very good question from one of my Harvard colleague Prof. Jim Anderson, world renown atmospheric chemist, with who I have collaborated He used my lasers for chemical sensing in the atmosphere  Federico: Can you eliminate the lens in front of the laser? I have no space for it in my drones! Apply a flat contact lens directly on the laser ! This was the beginning of flat optics!
Designer metasurfaces • Can we design an artificial surface (metasurface) that refracts a light beam by an arbitrary angle (generalized Snell’s law)? • Simple application of Fermat’s principle: light beam follows the path of minimum time ( for the experts “path of stationary phase”) • Can we make a flat lens with no spherical aberrations: i.e. a wavelength size focal spot? N.Yu and F. Capasso, Nature Materials 13, 139 (2014) N. Yu et al., Science 334, 333 (2011)
Refraction
Refraction: Snell’s law “Light beam chooses the path of minimum time” Although named after Dutch astronomer Willebrord Snellius (1580–1626), the law was first accurately described by the Arab scientist Ibn Sahl at Baghdad court 984 AD Pierre de Fermat 1601-1665 Ratio of angles depends on ratio of speed of light in air and in water
32 The dilemma was first used by Feynman in his Lectures on Physics to explain the refraction of light on the interface between two optical media. Lifeguard’s dilemma: what is the best route for a lifeguard to reach a drowning man?
t i Optimal path is that of minimum time Ratio of angles depends on ratio of life guard speed on land and in water 1 1 Sin( ) Sin( ) 0 Sin( ) Sin( ) 0 t i sea land t i t i v v n n c c         Light beam chooses the path of minimum time
Cliff of varying height Moher cliffs, Ireland
What is the analogue of the steep cliff of varying height for a light beam ? Can we design the interface between two media to bend light in arbitrary ways ? We need to design an interface which can delay light by a different amount of time at each point ta refraction Side view ia Light beam t1 t2 t3 t4
 = 8 m Meta-surface for demonstrating generalized laws of reflection and Refraction 36  50 nm thick antennas  Sub-wavelength resolution silicon air incident lightanomalous reflection anomalous refraction N. Yu et al., Science 334, 333 (2011)
ordinary refraction Incident light anomalous refraction t  37 Experiments: Anomalous refraction at perpendicular incidence t = Sin-1(- λ/) N. Yu et al., Science 334, 333 (2011)
Generalized Snell’s Law: anomalous refraction 38N. Yu, et al., Science 334, 333 (2011)
Why Lenses are thick ? n1 n2 Propagating Wavefront • All lenses suffer from distortions in the way they focus • Focal point is blurred by aberrations (spherical, astigmatism, coma, etc.) • Can be corrected by using multiple lenses, which however makes the optics much thicker, bulky and heavier
Can we make a planar (“flat”) lens? By structuring with nanotechnology a planar surface so that all rays converge to the same focus The surface is nanostructured: METASURFACE
Spherical Aberrations Coma Astigmatism Aberrations
Harvard John A. Paulson School of Engineering and Applied Sciences 3 Conventional Lens Manufacturing Ref: U.S. Patent 0085059 A1, Mar. 24, 2016.  Mobile phone camera (all plastic lenses) Front lens Compound lens (reduce chromatic aberration) Meniscus lens (spherical aberration)  Microscope objective lens • All lenses suffer from distortions in the way they focus • Focal point is blurred by aberrations (spherical, astigmatism, coma, etc.) • Can be corrected by using multiple lenses, which however makes the optics much thicker, bulky and heavier
Making a flat lens Francesco Aieta Patrice Genevet
Flat Lens: Eliminating Spherical Aberrations • For all rays to focus in point F the time for light to travel from each point PL of the lens to point F must be the same • For this to occur the antennas in any point PL must introduce a delay in the transmitted light to compensate for the different light propagation times between points P and F • Above are shown the results of our first flat lens with metallic nanostructures. Although it had a small focusing efficient it demonstrated the key point diffraction limited focusing with a single metasurface : a compelling application of the generalized law of refraction
Titanium Dioxide Metasurfaces: Completely transparent in the visible Negligible roughness, Vertical walls 46 100 nm Side view 600 nm R.C. Devlin, et al. Proc. Nat. Acad. Sci .113, 10473 (2016)
High performancemetalenses in the visible M.Khorasaninejad, W. T. Chen, R. C. Devlin, J.Oh, A. Y. Zhu ,F. Capasso, Science, June 3 2016 https://www.youtube.com/watch?v=ETx_fjM5pms
Fabricated Metalens 6 m 600 nm 2 m
500 nm F 500 nm E 500 nm D 500 nm B 500 nm C 500 nm A 405 nm532 nm660 nm Meta-Lens Objective Diffraction Limited Focusing: High Numerical Aperture +0.8 • Compares well to commercial objectives
Metasurfaces: complete wavefront control Secondary wavelets Primary wavefront Diameter  Straight-Forward Fabrication ■ Lithographically defined: same technology of chip making  Compact ■ Light weight, capability to be vertically integrated  Unprecedented Control of Dispersion  Overcome Limitations of Conventional Optics ■ Aberrations, multifunctionality Phase shifter Benefits  Huygens-Fresnel Principle 50
✓ Uniform amplitude ✓ 2π phase coverage M. Khorasaninejad et al. Nano Lett., 16, 7229 (2016). Diffraction limited metalens design Diameter  Numerical Aperture as High as 0.85  <600 nm Tall TiO2 Nanopillars
Harvard John A. Paulson School of Engineering and Applied Sciences 52 Scalability and Mass Production: Large Area Metalens 4 inch wafer 1 cm diameter  All-glass metalens  Nanometer-scale precision with high-throughput  160 million nanopillars per metalens Manufactured with deep ultraviolet (DUV) pr ojection lithography: used in semiconductor I C chip manufacturing. Unification of two in dustries: ICs and Optics J. S. Park, F. Capasso et al. Nano Letters 19, 8673 (2019)  2 mm diameter a-Si metalens on a 12-inch silica wafer by CMOS foundry (10,000/wafer)  DUV (193nm) dry projection lithography  First metalens-based NIR (λ= 940 nm) VGA camera module  1.5MP camera  Automotive applications  Benefits:  Uniform illumination  2X brighter compared to 4P plastic lenses refractive camera module  Simpler configuration *A spin-off startup from Capasso group; completed round A of investment with support from major strategic investors * Target is high volume markets  Demo shown at OSA Incubator of Flat Optics Washington DC , Feb. 28 , 2020
Achromatic Metalenses W. T. Chen, A. Y. Zhu, J. Sisler, Z. Bharwani, F. Capasso, Nat. Commun. 10, 355 (2019) All wavelengths in the visible have the same focal length i.e. no chromatic aberration
Harvard John A. Paulson School of Engineering and Applied Sciences 54 Achromatic Metalens Chromatic Metalens
Harvard John A. Paulson School of Engineering and Applied Sciences White light focusing
Harvard John A. Paulson School of Engineering and Applied Sciences Metalens for High Resolution Endoscopes Hamid Pahlevani et al. Nature Photonics https://doi.org/10.1038/s41566-018-0224-2 metalens glass tube fiber drive cable ferrule NCF GRIN NCF tangential focus GRIN lens catheter NCF Ball Ball lens catheter Prism Metalens Metalens catheter 0 100 200 400 600 800-100-200 z (μm) 20 μm GRINlensBalllensMetalens 0 1  Collaboration with Mass General Hospital, Prof. Melissa Suter
Endoscopic imaging using metalens catheter Exvivohumanlungs invivo sheeplung Histological imagesOCT images epi: epithelium; bm: basement membrane; car: cartilage ves: blood vessels; alv: alveolar; gp: glandular patterns
Harvard John A. Paulson School of Engineering and Applied Sciences  Motivation: small, low power depth sensors Jumping spiders - an example of micro depth sensing platform  High computational power means a fancy GPU or cluster, whereas low power computations can be easily implemented on small platforms with limited energy budge such as cellphones, microrobots, drones etc. Bio-inspired metalens depth sensor L2 L1 Corneal lens Multi-layer semi-transparent retinae Depth information Prof. Todd ZicklerZhujun Shi
Harvard John A. Paulson School of Engineering and Applied Sciences  Metalens depth sensor that mimics the jumping spider.   Co-design of hardware (optics) and software (algorithm)  Metalens that simultaneously creates side-by-side two images of the same scene but with different amount of defocus. Bio-inspired metalens depth sensor Q. Guo et al. PNAS 116, 22959 (2019)
Harvard John A. Paulson School of Engineering and Applied Sciences  Depth map reconstruction equation  Advantages: • Greatly reduced computational burden: 10 times less computation then typical stereo or light field depth sensors. • High speed: ~160 frame per second (fps) (for comparison, standard movies are 24 fps). • Snapshot, compact, lightweight. Depth from Defocus • Amount of computation = floating point operations per output pixel (FLOPS). Our method uses ~600 FLOPS, whereas traditional stereo depth sensing requires ~ 7000 FLOPS. Make FLOPS as small as possible: small chips at high speed and low power consumption.
Harvard John A. Paulson School of Engineering and Applied Sciences Results 0.28m 0.33m 0.38m 0.43m 0.48m Fruit flies Water stream Candle flames Slanted plane with texts • Working range: 30-40 cm • Depth resolution: ~3% of the true depth • Working range and resolution can be adjusted by modifying the metalens design.
Results Click on slide for movie
F. Capasso, Nanophotonics, 6 953 (2018)  Metasurfaces provide arbitrary control of the wavefront (phase, amplitude and polarization)  Metasurfaces enable flat optics: compact, thinner, easier fabrication and alignment  Multifunctionality: single flat optical components can replace multiple standard components  Flat Optics for a wide range of optical components (lenses, holograms, polarizers, phase plates, etc.) and applications: machine vision, biomed imaging, drones, polarimetry, polarization sensitive cameras  Same foundries will manufacture camera sensor and lenses using same technology (deep-UV stepper) CMOS compatible flat optics platform for high volume markets: Examples: lenses in cell phone camera modules will be replaced by metalenses fabricated by DUV lithography (same foundry that makes the sensor chip) Displays, wearable optics (augmented reality).  Metasurfaces can generate arbitrary vector beams (structured light) well beyond the capabilities of SLM  Importance of inverse design, co-design of hardware & software, impact of AI on optics Our Vision for Planar (“Flat”) Optics
Flat Optics Future High NA Optics Great Synergy with Fiber Optics: e.g.: Non-Invasive Imaging for Biomedical Application Major opportunity in Mid-infrared due to poor refractory materials Smart Phones Strechable Materials Wearable Displays: RGB lenses for augmented reality White Lighting
Thank you and have Fun with Science and Technology Federico Capasso John A. Paulson School of Engineering and Applied Sciences Harvard University http://www.seas.harvard.edu/ capasso

More Related Content

PPTX
Ferrites
byNikita Gupta
 
PPTX
Computational physics
byMuhammadUmairWahid
 
PPTX
Quantum Dots
byGreen University of Bangladesh
 
PPT
Quantum dots
byMaaz Hasan
 
PPTX
Quantum levitation
byabhik_24
 
PPTX
Nanomaterial and meta materials
byDeepak Raj
 
PPTX
Characterization of nanoparticles
byRAM PRAKASH
 
PPTX
Properties of nano materials
byMohd. Bilal
 
Ferrites
byNikita Gupta
 
Computational physics
byMuhammadUmairWahid
 
Quantum Dots
byGreen University of Bangladesh
 
Quantum dots
byMaaz Hasan
 
Quantum levitation
byabhik_24
 
Nanomaterial and meta materials
byDeepak Raj
 
Characterization of nanoparticles
byRAM PRAKASH
 
Properties of nano materials
byMohd. Bilal
 

What's hot

PPTX
Chemical Vapour Deposition
byaroosa khan
 
PPTX
Quantum dots and their applications
byDragon5588
 
PPTX
Lattice dynamics
bybarbie9891712518
 
PPTX
PLASMA DIAGNOSTIC BY ELECTRIC PROBE(single and double probe)
byAnitaMalviya
 
PPTX
Mems introduction
byKaushal Pant
 
PPTX
Michelson interferometer
byJeyaMangalam
 
PPTX
Mxenes presentation.pptx
byTouhidBinAnwar
 
PDF
Liquid Penetrant Testing-Penetrants
byMani Vannan M
 
PPTX
Metamaterials
byShuvan Prashant
 
PPTX
Thin films
byNischith Nbs
 
PPTX
Nanoimprint lithography (NIL)
byPreeti Choudhary
 
PPT
Non Destructive Testing Of Materials
byVinay M
 
PDF
APPLICATIONS OF METAMATERIAL IN ANTENNA ENGINEERING
byInternational Journal of Technical Research & Application
 
PPTX
Laser
byRUSHIT PATEL
 
PPTX
Scanning electron microscopy
byGanesh Shinde
 
PPSX
Artificial intelligence in the design of microstrip antenna
byRaj Kumar Thenua
 
PPTX
Michelsons interferometer
byGitam University
 
PPTX
Lithography techniques,types
byANJANI S
 
PDF
Scanning acoustic microscopy microelectronics Failure analysis - counterfei...
byyavkos
 
PPTX
Pelletron and van de graff generator
byHoney Ch
 
Chemical Vapour Deposition
byaroosa khan
 
Quantum dots and their applications
byDragon5588
 
Lattice dynamics
bybarbie9891712518
 
PLASMA DIAGNOSTIC BY ELECTRIC PROBE(single and double probe)
byAnitaMalviya
 
Mems introduction
byKaushal Pant
 
Michelson interferometer
byJeyaMangalam
 
Mxenes presentation.pptx
byTouhidBinAnwar
 
Liquid Penetrant Testing-Penetrants
byMani Vannan M
 
Metamaterials
byShuvan Prashant
 
Thin films
byNischith Nbs
 
Nanoimprint lithography (NIL)
byPreeti Choudhary
 
Non Destructive Testing Of Materials
byVinay M
 
APPLICATIONS OF METAMATERIAL IN ANTENNA ENGINEERING
byInternational Journal of Technical Research & Application
 
Laser
byRUSHIT PATEL
 
Scanning electron microscopy
byGanesh Shinde
 
Artificial intelligence in the design of microstrip antenna
byRaj Kumar Thenua
 
Michelsons interferometer
byGitam University
 
Lithography techniques,types
byANJANI S
 
Scanning acoustic microscopy microelectronics Failure analysis - counterfei...
byyavkos
 
Pelletron and van de graff generator
byHoney Ch
 

Similar to Federico Capasso: Photonics as Design

PDF
Tomorrow Today - a Laser Science Newsletter, March 2014
byLaser Science
 
PPTX
laser remote sensing
bysamira mohammadpour
 
PDF
Applications of Quantum Cascade Lasers
bysumeetkv
 
PDF
Lanthanide-Doped Mid-Infrared Materials
byBrian Walsh
 
PPTX
CLaDS Marblar Feb 13
bymarblar
 
PDF
Schlossberg - Lasers and Optics - Spring Review 2013
byThe Air Force Office of Scientific Research
 
PPTX
LASER CO2 and Nd:YAG
byAman Dhanda
 
PPTX
Laser,Optical Fibres and Ultrasonics
byNisarg Amin
 
PDF
Gas sennsor with strip waveguide
byRobin Singh
 
PDF
Irsens
bydalgetty
 
PPTX
Plasmatec
byDoc Jones
 
PPT
Lasers basics mechanism and principles
byChaitanya Areti
 
PPTX
LASER & APPLICATIONS
byArun Ashok
 
PPTX
Diploma sem 2 applied science physics-unit 5-chap-3 laser
byRai University
 
PPTX
Laser wps office
byjayanti ratna
 
PPTX
Uint 3 advance laser meterology
byS.DHARANI KUMAR
 
PPTX
Lasers
byEdigniteNGO
 
PPT
Terahertz_Applications
bykrishslide
 
PDF
Brolis Semiconductors: Targeting Spectroscopy with Antimonide Sources
byKristijonas Vizbaras
 
PPT
Laser characteristics as applied to medicine and biology
bykaroline Enoch
 
Tomorrow Today - a Laser Science Newsletter, March 2014
byLaser Science
 
laser remote sensing
bysamira mohammadpour
 
Applications of Quantum Cascade Lasers
bysumeetkv
 
Lanthanide-Doped Mid-Infrared Materials
byBrian Walsh
 
CLaDS Marblar Feb 13
bymarblar
 
Schlossberg - Lasers and Optics - Spring Review 2013
byThe Air Force Office of Scientific Research
 
LASER CO2 and Nd:YAG
byAman Dhanda
 
Laser,Optical Fibres and Ultrasonics
byNisarg Amin
 
Gas sennsor with strip waveguide
byRobin Singh
 
Irsens
bydalgetty
 
Plasmatec
byDoc Jones
 
Lasers basics mechanism and principles
byChaitanya Areti
 
LASER & APPLICATIONS
byArun Ashok
 
Diploma sem 2 applied science physics-unit 5-chap-3 laser
byRai University
 
Laser wps office
byjayanti ratna
 
Uint 3 advance laser meterology
byS.DHARANI KUMAR
 
Lasers
byEdigniteNGO
 
Terahertz_Applications
bykrishslide
 
Brolis Semiconductors: Targeting Spectroscopy with Antimonide Sources
byKristijonas Vizbaras
 
Laser characteristics as applied to medicine and biology
bykaroline Enoch
 

Recently uploaded

PDF
PHYTOREMEDIATION OF HEAVY METALS IN SOIL
byswethaviji2005
 
PPTX
Biology - Study of Photosynthesis lecture.pptx
byyuzukiarciaga
 
PDF
Visible-light-presentation_20250831_103200_0000.pdf
bySamIntal
 
PDF
Rapid diagnosis and contamination of seafood and aquaculture products
byGirija90
 
PDF
Machine Learning Lectures -- Loss Functions (2)
byZahra Sadeghi
 
PDF
Machine Learning Lectures Explainable AI
byZahra Sadeghi
 
PPTX
Bioremediation anaerobic process, sulphur, nitrate, iron reduction, hydrocarb...
byNandhiniV90
 
PDF
Machine Learning Lectures Multi layer Neural Networks
byZahra Sadeghi
 
PPTX
Aerobic-and-Anaerobic-Digesters-Biological-Waste-Treatment-Technologies.pptx
byShanmugaPriya168919
 
PDF
Bioremedation - Dechlorination ,Types and process , advantage and disadvantage
byswathijagadeesan1402
 
PPTX
Water treatment BOD and COD , dissolved gases
byNandhiniV90
 
PPTX
Forensic-Ballistics, identification of Firearms
bysoulquimicaanalitica
 
PDF
BIOREMEDIATION -MICROBIAL LEACHING OF ORES AND ITS PROCESS
byswethaviji2005
 
PPT
Grade 8 - Chemistry - Acids and Alkalis.ppt
byEnas813292
 
PDF
s - Block Handwritten Notes PDF - Irfanullah Mehar - JJ Sir Chemistry - World...
byWorld of Wisdom
 
PDF
Bacteria - Structure, Cell Wall Classification, Nutrition Classification, Rep...
byA Biodiction : A Unit of Dr. Divya Sharma
 
PPTX
ICSE_Chemistry_Presentation_1.pptx_ICSE 10
byjagannthdas453
 
PDF
Machine Learning Lectures --- Likelihood
byZahra Sadeghi
 
PPTX
Celebrating Breakthroughs in Metal Organic Frameworks - A Poster Showcasing t...
byRunjhunDutta
 
PDF
Periodic Table ( आवर्त सारणी ) Chemistry Notes PDF @irfanullah_mehar @world_o...
byWorld of Wisdom
 
PHYTOREMEDIATION OF HEAVY METALS IN SOIL
byswethaviji2005
 
Biology - Study of Photosynthesis lecture.pptx
byyuzukiarciaga
 
Visible-light-presentation_20250831_103200_0000.pdf
bySamIntal
 
Rapid diagnosis and contamination of seafood and aquaculture products
byGirija90
 
Machine Learning Lectures -- Loss Functions (2)
byZahra Sadeghi
 
Machine Learning Lectures Explainable AI
byZahra Sadeghi
 
Bioremediation anaerobic process, sulphur, nitrate, iron reduction, hydrocarb...
byNandhiniV90
 
Machine Learning Lectures Multi layer Neural Networks
byZahra Sadeghi
 
Aerobic-and-Anaerobic-Digesters-Biological-Waste-Treatment-Technologies.pptx
byShanmugaPriya168919
 
Bioremedation - Dechlorination ,Types and process , advantage and disadvantage
byswathijagadeesan1402
 
Water treatment BOD and COD , dissolved gases
byNandhiniV90
 
Forensic-Ballistics, identification of Firearms
bysoulquimicaanalitica
 
BIOREMEDIATION -MICROBIAL LEACHING OF ORES AND ITS PROCESS
byswethaviji2005
 
Grade 8 - Chemistry - Acids and Alkalis.ppt
byEnas813292
 
s - Block Handwritten Notes PDF - Irfanullah Mehar - JJ Sir Chemistry - World...
byWorld of Wisdom
 
Bacteria - Structure, Cell Wall Classification, Nutrition Classification, Rep...
byA Biodiction : A Unit of Dr. Divya Sharma
 
ICSE_Chemistry_Presentation_1.pptx_ICSE 10
byjagannthdas453
 
Machine Learning Lectures --- Likelihood
byZahra Sadeghi
 
Celebrating Breakthroughs in Metal Organic Frameworks - A Poster Showcasing t...
byRunjhunDutta
 
Periodic Table ( आवर्त सारणी ) Chemistry Notes PDF @irfanullah_mehar @world_o...
byWorld of Wisdom
 

Federico Capasso: Photonics as Design

  • 1.
    Photonics as Design FedericoCapasso John A. Paulson School of Engineering and Applied Sciences Harvard University http://www.seas.harvard.edu/ capasso  I am designer of new materials with man-made electronic and optical properties, built using nanotechnology  Here I concentrate on the most important results of my group: quantum cascade lasers and flat optics
  • 3.
    • Light-technologies providesolutions to global challenges • Light sciences are a cross-cutting discipline in the 21st century Ban Ki Moon The International Year of Light and Light-based Technologies 2015 UNESCO Opening Ceremony
  • 4.
    Light-technologies provide solutionsto global challenges Environmental monitoring Networks & Lighting (LED) Atom-like systems for nanoscale MRI, in vivo functional imaging Flat Optics : Replacing lenses in a wide range of applications Energy & Lighting Environment Healthcare Communications Security Culture and Art
  • 5.
    The interferometer detectschanges in the difference between its two arms as small as 1/ten thousand of the proton size (one ten millionth of a billion of a meter) due to the stretching and compression of space-time caused by the catastrophic union of two black holes 1.3 billion years ago Far Reaching Impact of Optical Technology in Fundamental Science: Direct Detection of Gravitational Waves Cosmic Union of Two Black Holes: Extreme Physics and Extreme Optical Technology "There are more things in heaven and earth, Horatio, than are dreamt of in your philosophy” W. Shakespeare, Hamlet (1.5.167-8) Predicted by Einstein over 100 years ago!
  • 6.
    Chemistry Beryllium Aluminum Silicate, lauePhysics Biology Material Science The Nanometer:where sciences converge Why now? 11 nm = 1 billionth of a meter
  • 7.
    Beyond atoms andmolecules: nanoscale building blocks DNA 2 nm Carbon nanotube ~1-2 nm 5 nm Nanocrystal, aka quantum dot BIOLOGY CHEMISTRY PHYSICS GATHERED FROM DIFFERENT SCIENCES (P. Alivisatos) Metamaterial
  • 8.
    Molecular Beam Epitaxy(MBE) : Spray Painting Atoms ! Can deposit 1 atomic layer! • A very precisely defined mixture of atoms to give EXACTLY the desired material composition! • Artificial Man-made materials by Design: enormous potential for science and technology Invented by Alfred Y. Cho; Bell Laboratories 1968-69 We collaborated for 25 years COMMERCIAL MBE SYSTEM 1 nm = 1 billionth of a meter
  • 9.
    Birth of theQuantum Cascade Laser Jan. 14, 1994 , Bell Labs J. Faist, F. Capasso, D. L. Sivco, C. Sirtori, A. L. Hutchinson, A. Y. Cho, Science 264, 553 (1994). Charles H. Townes, Nobel Laureate for the Laser: “This represents a remarkable combination of excellent solid-state and laser physics with new solid-state technology. It opens the door to very important new laser possibilities, ones I hope will be pursued and achieved”
  • 10.
    New class oflaser materials designed bottom up using Quantum Mechanics J. Faist, F. Capasso, D.L. Sivco, C. Sirtori, A.L. Hutchinson, A.Y. Cho, Science 264, 553, (1994) Layer Thickness determines the wavelength !
  • 11.
    Laser wavelength canbe changed by varying thickness of layers to match almost any molecular fingerprint : detection of chemicals in tiny concentrations Quantum Cascade Laser: Passing current through nanometer thick layers leads to emission of laser light
  • 12.
    The cascade Molecular BeamEpitaxy 45nm "MINIGAP" Zone de transport Zone d ’émission 3 2 1 e- e- "MINIBANDE" CASCADE scheme : Recycling of carriers; N periods = N photons per carrier Injector active region
  • 13.
    Spectral coverage oflasers 100 200 300 400 500 600 700 800 900 1,000 3,000 30,000 Ultraviolet Visible Near-infrared Mid-infrared terahertz HeNe 633 nm Ruby 694 nm Nd:YAG 1064 nm XeF 351 nm XeCl 308 nm KrF 248 nm ArF 193 nm Ti:sapphire 700-1000 nm Ar-ion 364-514 nm Diode Dye CO2 10.6 µm Quantum Cascade Laser have filled this gap, Enabling countless scientific and technological applicationns Er:YAG 2.94 µm
  • 14.
    Molecular Fingerprint Region MicrowavesTHz Mid-IR Near -IR UV Mid-Infrared: Molecular Fingerprint Region Mid-Infrared: Every molecule has a unique absorption fingerprint → chemical sensing with high sensitivity and selectivity Major Applications are: Sensors and spectroscopy • Industrial process control • Quality control of chemical processes • Detection of explosives and hazardous gases • Compliance testing of tablet, capsules, powders • Medical: breath analysis, tissue imaging • Environment / Energy: pollution monitoring, • atmospheric chemistry
  • 15.
    15 Quantum Cascade LaserProducts Cover The Entire Mid-Infrared Peak Pulsed Laser Performance M2095-PX QCL: D0102 M2068-PX QCL: HD0364 M2080-PX QCL: D0470 M2049-PX QCL: D0519 M2042-PX QCL: J0017 M2058-PX QCL: D0454 M2052-P QCL: KD0370 M2100-PX QCL: D0398 M2130-PX QCL: D0820 M2038-P QCL: J0162 M2035-P QCL: J0092 M2040-P QCL: D0571 • Largest product portfolio • CW and pulsed • Fastest tuning • Highest fidelity • Best technical support
  • 16.
    1E-5 1E-6 1E-7 1E-8 1E-9 1E-10 1E-11 1E-12 PowerSpectralDensity(W/2cm- 1) Wavelength (µm) Uncooled Enables High-speed, high-resolution acquisition Liquids Solids Tissues …aswell as semiconductors, powders, and slurries… The QCL Advantage Great potential as a source in FTIR spectrometers: e. g. spectroscopy of proteins in a water environment
  • 17.
    The QCL enablesa broad range of chemical sensing applications Life Sciences Environmental Sciences Materials Science 1800 1700 1600 1500 1200 1100 1000 9001400 1300 Absorption Wavenumber (cm-1) Proteins β-sheet Proteins α-helical RNA DNA Lipids Lipids Collagen Glycogen
  • 18.
    Enabled by theQCL: Pharmaceutical Drug Development Keles et al. Org. Process Res. Dev. (2017) Petibois et al, Chem. Sci., 2017 Real-time, Small-scale Drug Synthesis Pre-clinical Mouse Brain Chemical Mapping Drug Quality Control Courtesy: Tim Day, Daylight Solutions DRS
  • 19.
    Enabled by theQCL: Life Sciences Protein Folding Dynamics Faist et al. Analytical Chemistry (2018) Lendl et al. Analytical Chemistry (2018) Protein Secondary Structure Blood Biomarker Discovery Hughes et al. Sci. Reports (2016) Cancer Free Brain Cancer Breast Cancer Lung Cancer Skin Cancer Courtesy: Tim Day, Daylight Solutions DRS
  • 20.
    Powered by theQCL: Aircraft Protection Pollock, et al. The Infrared and Electro-Optical Systems Handbook, Vol. 7, Countermeasure Systems (1993) Small SWaP enables installation on lightweight rotary-wing and commercial aircraft Simplistic architectures facilitate military ruggedized systems for harsh environments Inherent reliability provides significant lifecycle cost reduction compared to legacy systems Courtesy: Tim Day, Daylight Solutions DRS High Power: > 5 Watt CW at λ ~ 4.5 µm 2016 US Military qualifies QCL for aircraft protection
  • 21.
    QC Laser Multipass cavity Detector Spectroscopyand Chemical Sensing with Lasers • Fundamental vibration modes of molecules are in the Mid-IR – Chemically and isotopically sensitive N O
  • 22.
    Real-time Exhaled HumanNH3 Breath Measurements Successful testing of a 2nd generation breath ammonia monitor installed in a clinical environment.(Johns Hopkins, Baltimore, MD and St. Luke’s Hospital, Bethlehem, PA) 14:24:00 14:24:20 14:24:40 14:25:00 14:25:20 0 50 100 150 200 250 300 350 400 NH3 concentration[ppb] Time [HH:MM:SS] Breath data from NH3 Rice sensor Max NH3 concentration is: 351 ppb 0 1000 2000 3000 4000 0 2 4 6 8 10 12 0 50 100 150 200 250 CO2 concentration[%] AirwayPressure[mbar] Point [-] Pressure CO2 NH3 NH3 concnetration[ppb] Airway pressure (black), CO2 (red), and NH3 (blue) profiles of a single breath exhalation lasting 40sec. Minimum detectable concentration of NH3 is: ~ 6 ppbv at 967.35 cm-1 (1σ; 1 s time resolution)
  • 24.
    Pole-to-Pole Observations ofCarbon Cycle and Greenhouse Gases using Quantum Cascade Laser Spectrometers Gulf Stream V Aircraft QCLs for CO2, CO, CH4, N2O LATITUDE AND ALTITUDE HIGH PRECISION PROFILES OF TRACERS FOR GLOBAL CIRCULATION MODELS PRECISION: (concentration) CO2 30 ppb (340 ppm) CO 0.2 ppb (80 ppb) CH4 0.8 ppb (1800 ppb) N2O 0.1 ppb (320 ppb) Prof. STEVEN WOFSY, HAVARD e ALTITUDE PROFILES CO CH4 N2O CO2 New information about the emissions of greenhouse gases into the atmosphere: critical for predicting climate change
  • 25.
    ATMOSPHERIC (Troposphere &Stratosphere) TRACE GAS MEASUREMENTS WITH QCLs TRACE GAS cm-1 std dev 1s ppb 76 m path LoD ppb 100 s NH3 967 0.2 0.06 C2H4 960 1 0.5 O3 1050 1.5 0.6 CH4 1270 1 0.4 N2O 1270 0.4 0.2 H2O2 1267 3 1 SO2 1370 1 0.5 NO2 1600 0.2 0.1 HONO 1700 0.6 0.3 HNO3 1723 0.6 0.3 HCHO 1765 0.3 0.15 HCOOH 1765 0.3 0.15 NO 1900 0.6 0.3 OCS 2071 0.06 0.03 CO 2190 0.4 0.2 N2O 2240 0.2 0.1 13CO2/ 12CO2 2311 0.5 ‰ 0.1 ‰ LIGHTWEIGHT MULTIPASS CELL (76m) LASER 1 CH4 1270.785 N2O 1271.078 CO 2179.772 LASER 2 ABSORPTION SPECTRUM DUAL-LASER INSTRUMENT DESIGN
  • 26.
    • The measurementsresolve the vertical and horizontal structure of the atmosphere: first to provide a high-resolution section of the atmosphere— the QCL spectrometers are uniquely capable of making this kind of observation. • The patterns provide new information about the locations and strengths of emissions of greenhouse gases to the atmosphere.
  • 27.
    27 NASA Altair UAV Dronefor detection of chemical in impervious regions Jim Anderson, Harvard
  • 28.
    Transition from quantumcascade lasers to flat optics  Was facilitated by a very good question from one of my Harvard colleague Prof. Jim Anderson, world renown atmospheric chemist, with who I have collaborated He used my lasers for chemical sensing in the atmosphere  Federico: Can you eliminate the lens in front of the laser? I have no space for it in my drones! Apply a flat contact lens directly on the laser ! This was the beginning of flat optics!
  • 29.
    Designer metasurfaces • Canwe design an artificial surface (metasurface) that refracts a light beam by an arbitrary angle (generalized Snell’s law)? • Simple application of Fermat’s principle: light beam follows the path of minimum time ( for the experts “path of stationary phase”) • Can we make a flat lens with no spherical aberrations: i.e. a wavelength size focal spot? N.Yu and F. Capasso, Nature Materials 13, 139 (2014) N. Yu et al., Science 334, 333 (2011)
  • 30.
  • 31.
    Refraction: Snell’s law “Lightbeam chooses the path of minimum time” Although named after Dutch astronomer Willebrord Snellius (1580–1626), the law was first accurately described by the Arab scientist Ibn Sahl at Baghdad court 984 AD Pierre de Fermat 1601-1665 Ratio of angles depends on ratio of speed of light in air and in water
  • 32.
    32 The dilemma wasfirst used by Feynman in his Lectures on Physics to explain the refraction of light on the interface between two optical media. Lifeguard’s dilemma: what is the best route for a lifeguard to reach a drowning man?
  • 33.
    t i Optimal path isthat of minimum time Ratio of angles depends on ratio of life guard speed on land and in water 1 1 Sin( ) Sin( ) 0 Sin( ) Sin( ) 0 t i sea land t i t i v v n n c c         Light beam chooses the path of minimum time
  • 34.
    Cliff of varyingheight Moher cliffs, Ireland
  • 35.
    What is theanalogue of the steep cliff of varying height for a light beam ? Can we design the interface between two media to bend light in arbitrary ways ? We need to design an interface which can delay light by a different amount of time at each point ta refraction Side view ia Light beam t1 t2 t3 t4
  • 36.
     = 8m Meta-surface for demonstrating generalized laws of reflection and Refraction 36  50 nm thick antennas  Sub-wavelength resolution silicon air incident lightanomalous reflection anomalous refraction N. Yu et al., Science 334, 333 (2011)
  • 37.
    ordinary refraction Incident light anomalous refraction t  37 Experiments: Anomalousrefraction at perpendicular incidence t = Sin-1(- λ/) N. Yu et al., Science 334, 333 (2011)
  • 38.
    Generalized Snell’s Law:anomalous refraction 38N. Yu, et al., Science 334, 333 (2011)
  • 40.
    Why Lenses arethick ? n1 n2 Propagating Wavefront • All lenses suffer from distortions in the way they focus • Focal point is blurred by aberrations (spherical, astigmatism, coma, etc.) • Can be corrected by using multiple lenses, which however makes the optics much thicker, bulky and heavier
  • 41.
    Can we makea planar (“flat”) lens? By structuring with nanotechnology a planar surface so that all rays converge to the same focus The surface is nanostructured: METASURFACE
  • 42.
  • 43.
    Harvard John A.Paulson School of Engineering and Applied Sciences 3 Conventional Lens Manufacturing Ref: U.S. Patent 0085059 A1, Mar. 24, 2016.  Mobile phone camera (all plastic lenses) Front lens Compound lens (reduce chromatic aberration) Meniscus lens (spherical aberration)  Microscope objective lens • All lenses suffer from distortions in the way they focus • Focal point is blurred by aberrations (spherical, astigmatism, coma, etc.) • Can be corrected by using multiple lenses, which however makes the optics much thicker, bulky and heavier
  • 44.
    Making a flatlens Francesco Aieta Patrice Genevet
  • 45.
    Flat Lens: EliminatingSpherical Aberrations • For all rays to focus in point F the time for light to travel from each point PL of the lens to point F must be the same • For this to occur the antennas in any point PL must introduce a delay in the transmitted light to compensate for the different light propagation times between points P and F • Above are shown the results of our first flat lens with metallic nanostructures. Although it had a small focusing efficient it demonstrated the key point diffraction limited focusing with a single metasurface : a compelling application of the generalized law of refraction
  • 46.
    Titanium Dioxide Metasurfaces:Completely transparent in the visible Negligible roughness, Vertical walls 46 100 nm Side view 600 nm R.C. Devlin, et al. Proc. Nat. Acad. Sci .113, 10473 (2016)
  • 47.
    High performancemetalenses inthe visible M.Khorasaninejad, W. T. Chen, R. C. Devlin, J.Oh, A. Y. Zhu ,F. Capasso, Science, June 3 2016 https://www.youtube.com/watch?v=ETx_fjM5pms
  • 48.
  • 49.
    500 nm F 500 nm E 500 nm D 500 nm B 500 nm C 500 nm A 405 nm532 nm660nm Meta-Lens Objective Diffraction Limited Focusing: High Numerical Aperture +0.8 • Compares well to commercial objectives
  • 50.
    Metasurfaces: complete wavefrontcontrol Secondary wavelets Primary wavefront Diameter  Straight-Forward Fabrication ■ Lithographically defined: same technology of chip making  Compact ■ Light weight, capability to be vertically integrated  Unprecedented Control of Dispersion  Overcome Limitations of Conventional Optics ■ Aberrations, multifunctionality Phase shifter Benefits  Huygens-Fresnel Principle 50
  • 51.
    ✓ Uniform amplitude ✓2π phase coverage M. Khorasaninejad et al. Nano Lett., 16, 7229 (2016). Diffraction limited metalens design Diameter  Numerical Aperture as High as 0.85  <600 nm Tall TiO2 Nanopillars
  • 52.
    Harvard John A.Paulson School of Engineering and Applied Sciences 52 Scalability and Mass Production: Large Area Metalens 4 inch wafer 1 cm diameter  All-glass metalens  Nanometer-scale precision with high-throughput  160 million nanopillars per metalens Manufactured with deep ultraviolet (DUV) pr ojection lithography: used in semiconductor I C chip manufacturing. Unification of two in dustries: ICs and Optics J. S. Park, F. Capasso et al. Nano Letters 19, 8673 (2019)  2 mm diameter a-Si metalens on a 12-inch silica wafer by CMOS foundry (10,000/wafer)  DUV (193nm) dry projection lithography  First metalens-based NIR (λ= 940 nm) VGA camera module  1.5MP camera  Automotive applications  Benefits:  Uniform illumination  2X brighter compared to 4P plastic lenses refractive camera module  Simpler configuration *A spin-off startup from Capasso group; completed round A of investment with support from major strategic investors * Target is high volume markets  Demo shown at OSA Incubator of Flat Optics Washington DC , Feb. 28 , 2020
  • 53.
    Achromatic Metalenses W. T.Chen, A. Y. Zhu, J. Sisler, Z. Bharwani, F. Capasso, Nat. Commun. 10, 355 (2019) All wavelengths in the visible have the same focal length i.e. no chromatic aberration
  • 54.
    Harvard John A.Paulson School of Engineering and Applied Sciences 54 Achromatic Metalens Chromatic Metalens
  • 55.
    Harvard John A.Paulson School of Engineering and Applied Sciences White light focusing
  • 56.
    Harvard John A.Paulson School of Engineering and Applied Sciences Metalens for High Resolution Endoscopes Hamid Pahlevani et al. Nature Photonics https://doi.org/10.1038/s41566-018-0224-2 metalens glass tube fiber drive cable ferrule NCF GRIN NCF tangential focus GRIN lens catheter NCF Ball Ball lens catheter Prism Metalens Metalens catheter 0 100 200 400 600 800-100-200 z (μm) 20 μm GRINlensBalllensMetalens 0 1  Collaboration with Mass General Hospital, Prof. Melissa Suter
  • 57.
    Endoscopic imaging usingmetalens catheter Exvivohumanlungs invivo sheeplung Histological imagesOCT images epi: epithelium; bm: basement membrane; car: cartilage ves: blood vessels; alv: alveolar; gp: glandular patterns
  • 58.
    Harvard John A.Paulson School of Engineering and Applied Sciences  Motivation: small, low power depth sensors Jumping spiders - an example of micro depth sensing platform  High computational power means a fancy GPU or cluster, whereas low power computations can be easily implemented on small platforms with limited energy budge such as cellphones, microrobots, drones etc. Bio-inspired metalens depth sensor L2 L1 Corneal lens Multi-layer semi-transparent retinae Depth information Prof. Todd ZicklerZhujun Shi
  • 59.
    Harvard John A.Paulson School of Engineering and Applied Sciences  Metalens depth sensor that mimics the jumping spider.   Co-design of hardware (optics) and software (algorithm)  Metalens that simultaneously creates side-by-side two images of the same scene but with different amount of defocus. Bio-inspired metalens depth sensor Q. Guo et al. PNAS 116, 22959 (2019)
  • 60.
    Harvard John A.Paulson School of Engineering and Applied Sciences  Depth map reconstruction equation  Advantages: • Greatly reduced computational burden: 10 times less computation then typical stereo or light field depth sensors. • High speed: ~160 frame per second (fps) (for comparison, standard movies are 24 fps). • Snapshot, compact, lightweight. Depth from Defocus • Amount of computation = floating point operations per output pixel (FLOPS). Our method uses ~600 FLOPS, whereas traditional stereo depth sensing requires ~ 7000 FLOPS. Make FLOPS as small as possible: small chips at high speed and low power consumption.
  • 61.
    Harvard John A.Paulson School of Engineering and Applied Sciences Results 0.28m 0.33m 0.38m 0.43m 0.48m Fruit flies Water stream Candle flames Slanted plane with texts • Working range: 30-40 cm • Depth resolution: ~3% of the true depth • Working range and resolution can be adjusted by modifying the metalens design.
  • 62.
  • 63.
    F. Capasso, Nanophotonics,6 953 (2018)  Metasurfaces provide arbitrary control of the wavefront (phase, amplitude and polarization)  Metasurfaces enable flat optics: compact, thinner, easier fabrication and alignment  Multifunctionality: single flat optical components can replace multiple standard components  Flat Optics for a wide range of optical components (lenses, holograms, polarizers, phase plates, etc.) and applications: machine vision, biomed imaging, drones, polarimetry, polarization sensitive cameras  Same foundries will manufacture camera sensor and lenses using same technology (deep-UV stepper) CMOS compatible flat optics platform for high volume markets: Examples: lenses in cell phone camera modules will be replaced by metalenses fabricated by DUV lithography (same foundry that makes the sensor chip) Displays, wearable optics (augmented reality).  Metasurfaces can generate arbitrary vector beams (structured light) well beyond the capabilities of SLM  Importance of inverse design, co-design of hardware & software, impact of AI on optics Our Vision for Planar (“Flat”) Optics
  • 64.
    Flat Optics Future HighNA Optics Great Synergy with Fiber Optics: e.g.: Non-Invasive Imaging for Biomedical Application Major opportunity in Mid-infrared due to poor refractory materials Smart Phones Strechable Materials Wearable Displays: RGB lenses for augmented reality White Lighting
  • 65.
    Thank you andhave Fun with Science and Technology Federico Capasso John A. Paulson School of Engineering and Applied Sciences Harvard University http://www.seas.harvard.edu/ capasso