This document describes a new technology for deep brain optogenetic stimulation using miniature photonic probes. The probes aim to minimize brain damage and thermal load by using a scalable, mass-producible design with hundreds of densely packed, individually addressable emitting pixels on mechanical structures inspired by MEMS fabrication. A silicon photonic circuit delivers different wavelengths of light to each pixel using wavelength division multiplexing from a single optical fiber. This allows for independent control and complex illumination patterns without overlaps. Testing shows the probes can reliably excite neurons with low power and no photo-bleaching. Two-photon calcium imaging in mice validates the functional activation of neurons.
This document discusses electron beam lithography. It begins with an introduction and overview of electron beam lithography, explaining that it uses a beam of electrons to selectively expose and develop a resist film in order to create very small structures. It then provides a schematic of the electron beam lithography process and describes the lithography process steps. The document also covers the advantages of high resolution and no diffraction limit but disadvantages of low throughput and high costs. It includes details on electron beam sources and lenses used.
Electron projection lithography is a technique that uses electrons to transfer a pattern from a mask to a substrate. A focused electron beam is scanned across a patterned mask, and either the exposed or non-exposed regions of the resist-coated substrate are selectively removed, imparting the pattern. There are two main approaches to mask construction - scattering stencil masks use a thin membrane that absorbs little beam energy, while continuous membrane masks use a low atomic number membrane backed by a high atomic number layer to produce image contrasts. Electron projection lithography enables resolution as fine as 100nm and has applications in electronic circuit fabrication.
Transmission electron microscopy provides high resolution images of ultrastructures down to the nanometer scale. Specimen preparation for TEM involves fixation, dehydration, embedding, sectioning, and staining. The document outlines the principles and instrumentation of TEM, including the electron source, lenses, detectors, vacuum system, and electrical system. TEM is useful for medical and biological research applications such as virus identification, vaccine development, and disease surveillance.
Optical lithography moved to shorter wavelengths like deep ultraviolet (DUV) due to limitations of mercury lamps. Excimer lasers emitting at wavelengths like 248nm and 193nm were adopted as they met the requirements of high photon energy and shorter wavelengths. As feature sizes continued shrinking, even shorter wavelengths like extreme ultraviolet (EUV) at 13.5nm were needed. EUV lithography uses reflective optics since materials absorb at this wavelength, and requires operating in vacuum since all materials absorb EUV radiation. Key challenges for EUV include developing high power radiation sources, improving reflective mirror lifetimes against contamination, and developing suitable photoresists with low line edge roughness.
Extreme ultraviolet lithography (EUVL) is an advanced lithography technique needed to continue following Moore's Law and make more powerful microprocessors. EUVL uses light with a wavelength of 13.5nm, which is much shorter than visible light, allowing for smaller feature sizes. The EUVL process involves projecting a mask pattern through a series of reflective mirrors onto a photoresist-coated wafer under vacuum. Key aspects of EUVL include the use of reflective masks and all-reflective optical systems since materials absorb 13.5nm light. EUVL promises increased processor speeds and storage capacity but faces challenges like low mirror reflectivity and contamination control required for the vacuum environment.
TEM uses electron beams to image materials at high magnifications and resolutions. It works by transmitting electrons through a thin sample and forming an image from the electrons. Different imaging modes like bright field and dark field are used by selecting certain electron signals using an aperture. Electron diffraction is also possible, allowing analysis of crystal structures and orientations. Sample preparation into thin foils is important. TEM can reveal details of microstructures like defects, phases, and interfaces.
This document provides an overview of fluorescent microscopy. It begins with the history and basic principles, including Stokes shift and the advantages and disadvantages of fluorescent microscopy. Different types of fluorescent microscopes are described such as epifluorescent and confocal microscopes. Various fluorescent microscopic techniques are outlined, including wide-field, laser scanning, spinning disk, multi-photon, light sheet, and super-resolution microscopies. Sample preparation methods for fluorescent microscopy are also summarized, such as using synthetic fluorescent stains, immunofluorescence labeling, and genetically encoded fluorescent proteins.
This document discusses electron beam lithography techniques used in nanoscale fabrication. It begins with an overview of nanofabrication and conventional photolithography limitations. Then it describes electron beam lithography, including how the lithography system works, common techniques like direct writing and projection printing, types of electron beam resists, and benefits like high resolution. Challenges with the proximity effect and defects are discussed. Recent competing techniques like nanoimprint lithography are compared. Applications include fabrication of molds, tunnel junction devices, and use in x-ray and dip-pen nanolithographies. In conclusion, electron beam lithography continues to be important for nanoscale device fabrication.
This document discusses electron beam lithography. It begins with an introduction and overview of electron beam lithography, explaining that it uses a beam of electrons to selectively expose and develop a resist film in order to create very small structures. It then provides a schematic of the electron beam lithography process and describes the lithography process steps. The document also covers the advantages of high resolution and no diffraction limit but disadvantages of low throughput and high costs. It includes details on electron beam sources and lenses used.
Electron projection lithography is a technique that uses electrons to transfer a pattern from a mask to a substrate. A focused electron beam is scanned across a patterned mask, and either the exposed or non-exposed regions of the resist-coated substrate are selectively removed, imparting the pattern. There are two main approaches to mask construction - scattering stencil masks use a thin membrane that absorbs little beam energy, while continuous membrane masks use a low atomic number membrane backed by a high atomic number layer to produce image contrasts. Electron projection lithography enables resolution as fine as 100nm and has applications in electronic circuit fabrication.
Transmission electron microscopy provides high resolution images of ultrastructures down to the nanometer scale. Specimen preparation for TEM involves fixation, dehydration, embedding, sectioning, and staining. The document outlines the principles and instrumentation of TEM, including the electron source, lenses, detectors, vacuum system, and electrical system. TEM is useful for medical and biological research applications such as virus identification, vaccine development, and disease surveillance.
Optical lithography moved to shorter wavelengths like deep ultraviolet (DUV) due to limitations of mercury lamps. Excimer lasers emitting at wavelengths like 248nm and 193nm were adopted as they met the requirements of high photon energy and shorter wavelengths. As feature sizes continued shrinking, even shorter wavelengths like extreme ultraviolet (EUV) at 13.5nm were needed. EUV lithography uses reflective optics since materials absorb at this wavelength, and requires operating in vacuum since all materials absorb EUV radiation. Key challenges for EUV include developing high power radiation sources, improving reflective mirror lifetimes against contamination, and developing suitable photoresists with low line edge roughness.
Extreme ultraviolet lithography (EUVL) is an advanced lithography technique needed to continue following Moore's Law and make more powerful microprocessors. EUVL uses light with a wavelength of 13.5nm, which is much shorter than visible light, allowing for smaller feature sizes. The EUVL process involves projecting a mask pattern through a series of reflective mirrors onto a photoresist-coated wafer under vacuum. Key aspects of EUVL include the use of reflective masks and all-reflective optical systems since materials absorb 13.5nm light. EUVL promises increased processor speeds and storage capacity but faces challenges like low mirror reflectivity and contamination control required for the vacuum environment.
TEM uses electron beams to image materials at high magnifications and resolutions. It works by transmitting electrons through a thin sample and forming an image from the electrons. Different imaging modes like bright field and dark field are used by selecting certain electron signals using an aperture. Electron diffraction is also possible, allowing analysis of crystal structures and orientations. Sample preparation into thin foils is important. TEM can reveal details of microstructures like defects, phases, and interfaces.
This document provides an overview of fluorescent microscopy. It begins with the history and basic principles, including Stokes shift and the advantages and disadvantages of fluorescent microscopy. Different types of fluorescent microscopes are described such as epifluorescent and confocal microscopes. Various fluorescent microscopic techniques are outlined, including wide-field, laser scanning, spinning disk, multi-photon, light sheet, and super-resolution microscopies. Sample preparation methods for fluorescent microscopy are also summarized, such as using synthetic fluorescent stains, immunofluorescence labeling, and genetically encoded fluorescent proteins.
This document discusses electron beam lithography techniques used in nanoscale fabrication. It begins with an overview of nanofabrication and conventional photolithography limitations. Then it describes electron beam lithography, including how the lithography system works, common techniques like direct writing and projection printing, types of electron beam resists, and benefits like high resolution. Challenges with the proximity effect and defects are discussed. Recent competing techniques like nanoimprint lithography are compared. Applications include fabrication of molds, tunnel junction devices, and use in x-ray and dip-pen nanolithographies. In conclusion, electron beam lithography continues to be important for nanoscale device fabrication.
This document summarizes research on improving surface imaging resolution using movable microlenses integrated with localized plasmon structured illumination microscopy (LPSIM). Key points:
1) Dielectric microspheres (e.g. polystyrene, TiO2) can act as microlenses to magnify and transmit near-field object information to the far field, achieving superresolution beyond the diffraction limit.
2) An optical tweezer technique using radiation pressure from a focused infrared laser is demonstrated to trap and move microspheres on the sample surface.
3) Integrating movable microlenses with LPSIM achieved over 4x resolution improvement for polystyrene microspheres and over 6x for
This document discusses confocal laser scanning microscopy (CLSM). It begins by explaining that CLSM is an optical microscopy technique that increases resolution and contrast through the use of a pinhole aperture and laser light source. It then describes some of the key modifications from a traditional fluorescent microscope, including the pinhole aperture which cancels out-of-focus light and the use of a monochromatic laser beam. The document outlines the basic components and working principle of CLSM, noting that it works by focusing a laser onto samples, capturing returning fluorescent light through a pinhole, and using scanning mirrors and software to compile 2D and 3D images. Advantages include the ability to generate 3D images and thin optical sections, while disadvantages
2018 HM-Transmission electron microscopeHarsh Mohan
The document discusses transmission electron microscopy (TEM). It begins by explaining that TEM uses a beam of electrons to produce high resolution images of specimens. TEM provides higher resolution than optical microscopes because electrons have shorter wavelengths than visible light. The document then describes the basic components and functioning of TEM, including how electromagnetic lenses are used to focus the electron beam onto thin specimen samples and form magnified images. Specimen preparation methods for TEM like chemical fixation and staining are also covered.
Transmission electron microscopy (TEM) allows for direct imaging of nanoparticles and provides information about their atom distribution and surface. TEM works by firing electrons through an electron-transparent specimen using electromagnetic lenses, forming a magnified image based on how the specimen interacts with the electrons. Sample preparation is laborious and requires fixation, dehydration, resin infiltration, and ultrathin sectioning. TEM provides nanoscale imaging but requires expensive equipment and specialized facilities.
Practical skills in scanning electron microscopeNawfal Aldujaily
This document provides an overview of scanning electron microscopy (SEM) and its practical applications. It defines SEM and compares its resolution, depth of field, and magnification to optical microscopy. It describes the basic components and instrumentation of an SEM, including the electron gun, electromagnetic lenses, detectors, vacuum system and sample stage. It explains how SEM can be used to obtain topographical, morphological and compositional information from samples. It also discusses the signals produced during electron-sample interactions and how secondary electrons are used for topographical imaging while backscattered electrons provide compositional contrast. Finally, it notes that low vacuum mode and specialized holders allow SEM to image wet samples and reduce charging effects.
The document provides an overview of confocal microscopy. It discusses the history, starting with Minsky's invention of the confocal microscope in 1957. The instrumental design uses a pinhole to reject out-of-focus light and produce optical sections through a specimen. The principle involves illuminating a point on the specimen with a laser and detecting the resulting fluorescence through a pinhole, rejecting out-of-focus light. Applications include analyzing thick fluorescent specimens, 3D reconstruction, and improved resolution over conventional microscopy. Advantages are uniform illumination and better optical sections while limitations include resolution and photobleaching.
TEM provides high resolution imaging of materials through transmission of electrons. It can form images of microstructure features and also collect diffraction data from specimen areas. Different imaging modes like bright field and dark field are used depending on whether the main beam or diffracted beams are selected. Precise specimen preparation and instrument alignment are needed for high resolution lattice imaging. TEM allows visualization and characterization of microstructure features at nanometer scales.
TEM is a type of electron microscope that uses electron beams to produce magnified images of samples. TEMs can magnify up to 1 million times, allowing observation of ultrafine cell structures. Sample preparation is required to make specimens thin enough for electrons to pass through. TEMs are very expensive, ranging from $95,000 to over $100,000, but provide high resolution imaging useful for fields like nanotechnology, biology and materials science.
5. Microsocope ELECTRON MICROSCOPE (TEM & SEM ) - BasicsNethravathi Siri
Basics only
Electron beam is the source of illumination.
Image is produced by magnetic field.
Contrasting features between light microscope and electron microscope are
construction, working principle, specimen preparation, cost-expenses and designed
room (vacuum chamber).
Immersion lithography is a technique used in photolithography to enhance resolution. It works by placing a liquid such as water between the final optical element of the lithography system and the wafer. This allows higher numerical apertures compared to conventional "dry" lithography in air. The higher numerical aperture enables printing of smaller features. While it provides advantages, immersion lithography also presents challenges such as bubbles in the immersion liquid and interactions between the liquid and photoresist. It is widely adopted by semiconductor manufacturers for sub-45nm node fabrication.
THIS IS A PRESENTATION ON TRANSMISSION ELECTRON MICROSCOPY .(APART FROM DIFFERENT BOOKS,I HAVE ALSO TAKEN INFORMATION FROM DIFFERENT WEBSITES & PRESENTATIONS AVAILABLE IN NET ..
Guided nanophotonic devices and applications - Christiano de MatosCPqD
MackGraphe is a new research center at Mackenzie Presbyterian University dedicated to investigating the properties of graphene and other nanomaterials with an applied engineering perspective. The center initiated activities in 2012 with a focus on graphene synthesis, characterization, and photonic device development. Previous work included functionalizing optical fiber tips with carbon nanotubes for mode-locked fiber lasers and depositing polymer films inside hollow-core photonic crystal fibers. Current research interests include exploiting graphene's saturable absorption, nonlinearity, and plasmonic properties for all-integrated photonic devices based on nonlinear and plasmonic effects.
Examples of Various Imaging Techniques- SEM, AFM, TEM and FluorescenceJacob Feste
This document summarizes an experiment using SEM and AFM microscopy to image and characterize multi-walled carbon nanotubes (MWCNTs). SEM imaging provided estimated diameters of 60.9nm and lengths of 3.21um for the MWCNTs. AFM imaging was unsuccessful likely due to errors in MWCNT preparation that left unwanted material like calcium carbonate binding to the nanotubes, interfering with AFM parameter adjustments needed for clear imaging. While SEM imaging worked as expected for the conductive carbon nanotubes, AFM imaging requires a more uniform sample to produce high-quality images.
Pharmaceutical imaging techniques provide visual representations of objects like body parts or pharmaceutical products for quality control, data collection, or disease diagnosis using computerized methods like ultrasound or spectroscopy. Imaging technologies are gaining attention in the pharmaceutical industry due to their potential to accelerate drug discovery and development. Common techniques discussed in the document include chemical imaging, elemental imaging, digital imaging, fluorescence correlation spectroscopy, and micro-X-ray fluorescence, which are used for applications like content uniformity testing, particle characterization, counterfeit detection, and detecting drug distribution.
SEM provides information on a sample's surface composition through backscattered and secondary electrons. It has lower resolution than TEM but requires little sample preparation. TEM uses transmitted electrons to view a sample's inner structure and crystal structure at atomic resolution, but requires complex preparation of very thin samples and specialized grids for mounting. While TEM enables higher magnification and resolution, SEM operation is simpler and provides a larger field of view and depth of field.
Transmission electron microscopy (TEM) is a microscopy technique in which a beam of electrons is guided through an ultra thin specimen, interacting with the specimen as it passes through.An image is formed from the fundamental interaction of the electrons transmitted through the specimen; the image is magnified and focused onto an imaging device, such as a fluorescent screen, on a layer of photographic film, or to be observed by a sensor such as a CCD camera.
Difference between Light and Electron Microscopy Poorvaja Ganesan
this document provides the major differences between electron microscopy and light microscopy. This is one of the important chapters in Microbiology. Unit 1 Microbiology BT6202 notes. Anna university important 8 mark.
Fiber-optic cables are made of thin glass strands that carry digital information over long distances using pulses of light. They consist of a core and cladding layer that uses total internal reflection to transmit light signals with little degradation. Fiber-optic cables have advantages over metal cables in that they are less expensive, non-flammable, thinner, have higher carrying capacity and less signal degradation. They are used for telecommunications, cable TV, internet, and medical and mechanical imaging.
Photonic materials manipulate photons to achieve certain functions. Photonic crystals are a type of photonic material that displays unusual properties in interacting with light due to a periodic modulation of refractive index. They can trap light in cavities and waveguides by creating photonic band gaps that prevent light from propagating in certain directions. Potential applications of photonic crystals include photonic integrated circuits, lasers, sensors, and replacing conventional optical fibers.
The document discusses microscopy and different types of microscopes. It begins by defining microscopy as the technology that makes small objects visible to the human eye using microscopes. It then describes different types of microscopes, focusing on light microscopes and electron microscopes. Electron microscopes use a beam of electrons rather than light, allowing them to achieve much higher magnifications and resolving power than light microscopes. The document discusses the basic components and working principles of transmission electron microscopes and scanning electron microscopes. It also covers sample preparation techniques, applications, limitations, and recent research using electron microscopy.
Presentationon optical and electron microscopy by deepak kumar Drx Kumar
This document provides information on optical and electron microscopy. It discusses the basic principles and components of simple microscopes, compound microscopes, transmission electron microscopy, and scanning electron microscopy. Compound microscopes use lenses to magnify real images, allowing higher magnification than simple microscopes. Transmission electron microscopy uses electron beams and electromagnetic lenses to image very thin samples at resolutions up to 2.5 nm. Scanning electron microscopy scans sample surfaces with an electron beam to produce 3D images at magnifications up to 10,000x. Both electron microscopy techniques provide higher resolution than optical microscopy but have specific sample preparation and imaging requirements.
This document summarizes research on improving surface imaging resolution using movable microlenses integrated with localized plasmon structured illumination microscopy (LPSIM). Key points:
1) Dielectric microspheres (e.g. polystyrene, TiO2) can act as microlenses to magnify and transmit near-field object information to the far field, achieving superresolution beyond the diffraction limit.
2) An optical tweezer technique using radiation pressure from a focused infrared laser is demonstrated to trap and move microspheres on the sample surface.
3) Integrating movable microlenses with LPSIM achieved over 4x resolution improvement for polystyrene microspheres and over 6x for
This document discusses confocal laser scanning microscopy (CLSM). It begins by explaining that CLSM is an optical microscopy technique that increases resolution and contrast through the use of a pinhole aperture and laser light source. It then describes some of the key modifications from a traditional fluorescent microscope, including the pinhole aperture which cancels out-of-focus light and the use of a monochromatic laser beam. The document outlines the basic components and working principle of CLSM, noting that it works by focusing a laser onto samples, capturing returning fluorescent light through a pinhole, and using scanning mirrors and software to compile 2D and 3D images. Advantages include the ability to generate 3D images and thin optical sections, while disadvantages
2018 HM-Transmission electron microscopeHarsh Mohan
The document discusses transmission electron microscopy (TEM). It begins by explaining that TEM uses a beam of electrons to produce high resolution images of specimens. TEM provides higher resolution than optical microscopes because electrons have shorter wavelengths than visible light. The document then describes the basic components and functioning of TEM, including how electromagnetic lenses are used to focus the electron beam onto thin specimen samples and form magnified images. Specimen preparation methods for TEM like chemical fixation and staining are also covered.
Transmission electron microscopy (TEM) allows for direct imaging of nanoparticles and provides information about their atom distribution and surface. TEM works by firing electrons through an electron-transparent specimen using electromagnetic lenses, forming a magnified image based on how the specimen interacts with the electrons. Sample preparation is laborious and requires fixation, dehydration, resin infiltration, and ultrathin sectioning. TEM provides nanoscale imaging but requires expensive equipment and specialized facilities.
Practical skills in scanning electron microscopeNawfal Aldujaily
This document provides an overview of scanning electron microscopy (SEM) and its practical applications. It defines SEM and compares its resolution, depth of field, and magnification to optical microscopy. It describes the basic components and instrumentation of an SEM, including the electron gun, electromagnetic lenses, detectors, vacuum system and sample stage. It explains how SEM can be used to obtain topographical, morphological and compositional information from samples. It also discusses the signals produced during electron-sample interactions and how secondary electrons are used for topographical imaging while backscattered electrons provide compositional contrast. Finally, it notes that low vacuum mode and specialized holders allow SEM to image wet samples and reduce charging effects.
The document provides an overview of confocal microscopy. It discusses the history, starting with Minsky's invention of the confocal microscope in 1957. The instrumental design uses a pinhole to reject out-of-focus light and produce optical sections through a specimen. The principle involves illuminating a point on the specimen with a laser and detecting the resulting fluorescence through a pinhole, rejecting out-of-focus light. Applications include analyzing thick fluorescent specimens, 3D reconstruction, and improved resolution over conventional microscopy. Advantages are uniform illumination and better optical sections while limitations include resolution and photobleaching.
TEM provides high resolution imaging of materials through transmission of electrons. It can form images of microstructure features and also collect diffraction data from specimen areas. Different imaging modes like bright field and dark field are used depending on whether the main beam or diffracted beams are selected. Precise specimen preparation and instrument alignment are needed for high resolution lattice imaging. TEM allows visualization and characterization of microstructure features at nanometer scales.
TEM is a type of electron microscope that uses electron beams to produce magnified images of samples. TEMs can magnify up to 1 million times, allowing observation of ultrafine cell structures. Sample preparation is required to make specimens thin enough for electrons to pass through. TEMs are very expensive, ranging from $95,000 to over $100,000, but provide high resolution imaging useful for fields like nanotechnology, biology and materials science.
5. Microsocope ELECTRON MICROSCOPE (TEM & SEM ) - BasicsNethravathi Siri
Basics only
Electron beam is the source of illumination.
Image is produced by magnetic field.
Contrasting features between light microscope and electron microscope are
construction, working principle, specimen preparation, cost-expenses and designed
room (vacuum chamber).
Immersion lithography is a technique used in photolithography to enhance resolution. It works by placing a liquid such as water between the final optical element of the lithography system and the wafer. This allows higher numerical apertures compared to conventional "dry" lithography in air. The higher numerical aperture enables printing of smaller features. While it provides advantages, immersion lithography also presents challenges such as bubbles in the immersion liquid and interactions between the liquid and photoresist. It is widely adopted by semiconductor manufacturers for sub-45nm node fabrication.
THIS IS A PRESENTATION ON TRANSMISSION ELECTRON MICROSCOPY .(APART FROM DIFFERENT BOOKS,I HAVE ALSO TAKEN INFORMATION FROM DIFFERENT WEBSITES & PRESENTATIONS AVAILABLE IN NET ..
Guided nanophotonic devices and applications - Christiano de MatosCPqD
MackGraphe is a new research center at Mackenzie Presbyterian University dedicated to investigating the properties of graphene and other nanomaterials with an applied engineering perspective. The center initiated activities in 2012 with a focus on graphene synthesis, characterization, and photonic device development. Previous work included functionalizing optical fiber tips with carbon nanotubes for mode-locked fiber lasers and depositing polymer films inside hollow-core photonic crystal fibers. Current research interests include exploiting graphene's saturable absorption, nonlinearity, and plasmonic properties for all-integrated photonic devices based on nonlinear and plasmonic effects.
Examples of Various Imaging Techniques- SEM, AFM, TEM and FluorescenceJacob Feste
This document summarizes an experiment using SEM and AFM microscopy to image and characterize multi-walled carbon nanotubes (MWCNTs). SEM imaging provided estimated diameters of 60.9nm and lengths of 3.21um for the MWCNTs. AFM imaging was unsuccessful likely due to errors in MWCNT preparation that left unwanted material like calcium carbonate binding to the nanotubes, interfering with AFM parameter adjustments needed for clear imaging. While SEM imaging worked as expected for the conductive carbon nanotubes, AFM imaging requires a more uniform sample to produce high-quality images.
Pharmaceutical imaging techniques provide visual representations of objects like body parts or pharmaceutical products for quality control, data collection, or disease diagnosis using computerized methods like ultrasound or spectroscopy. Imaging technologies are gaining attention in the pharmaceutical industry due to their potential to accelerate drug discovery and development. Common techniques discussed in the document include chemical imaging, elemental imaging, digital imaging, fluorescence correlation spectroscopy, and micro-X-ray fluorescence, which are used for applications like content uniformity testing, particle characterization, counterfeit detection, and detecting drug distribution.
SEM provides information on a sample's surface composition through backscattered and secondary electrons. It has lower resolution than TEM but requires little sample preparation. TEM uses transmitted electrons to view a sample's inner structure and crystal structure at atomic resolution, but requires complex preparation of very thin samples and specialized grids for mounting. While TEM enables higher magnification and resolution, SEM operation is simpler and provides a larger field of view and depth of field.
Transmission electron microscopy (TEM) is a microscopy technique in which a beam of electrons is guided through an ultra thin specimen, interacting with the specimen as it passes through.An image is formed from the fundamental interaction of the electrons transmitted through the specimen; the image is magnified and focused onto an imaging device, such as a fluorescent screen, on a layer of photographic film, or to be observed by a sensor such as a CCD camera.
Difference between Light and Electron Microscopy Poorvaja Ganesan
this document provides the major differences between electron microscopy and light microscopy. This is one of the important chapters in Microbiology. Unit 1 Microbiology BT6202 notes. Anna university important 8 mark.
Fiber-optic cables are made of thin glass strands that carry digital information over long distances using pulses of light. They consist of a core and cladding layer that uses total internal reflection to transmit light signals with little degradation. Fiber-optic cables have advantages over metal cables in that they are less expensive, non-flammable, thinner, have higher carrying capacity and less signal degradation. They are used for telecommunications, cable TV, internet, and medical and mechanical imaging.
Photonic materials manipulate photons to achieve certain functions. Photonic crystals are a type of photonic material that displays unusual properties in interacting with light due to a periodic modulation of refractive index. They can trap light in cavities and waveguides by creating photonic band gaps that prevent light from propagating in certain directions. Potential applications of photonic crystals include photonic integrated circuits, lasers, sensors, and replacing conventional optical fibers.
The document discusses microscopy and different types of microscopes. It begins by defining microscopy as the technology that makes small objects visible to the human eye using microscopes. It then describes different types of microscopes, focusing on light microscopes and electron microscopes. Electron microscopes use a beam of electrons rather than light, allowing them to achieve much higher magnifications and resolving power than light microscopes. The document discusses the basic components and working principles of transmission electron microscopes and scanning electron microscopes. It also covers sample preparation techniques, applications, limitations, and recent research using electron microscopy.
Presentationon optical and electron microscopy by deepak kumar Drx Kumar
This document provides information on optical and electron microscopy. It discusses the basic principles and components of simple microscopes, compound microscopes, transmission electron microscopy, and scanning electron microscopy. Compound microscopes use lenses to magnify real images, allowing higher magnification than simple microscopes. Transmission electron microscopy uses electron beams and electromagnetic lenses to image very thin samples at resolutions up to 2.5 nm. Scanning electron microscopy scans sample surfaces with an electron beam to produce 3D images at magnifications up to 10,000x. Both electron microscopy techniques provide higher resolution than optical microscopy but have specific sample preparation and imaging requirements.
The document provides an overview of scanning electron microscopes (SEMs). It discusses the history and development of SEMs. Key components of SEMs are described, including the electron gun, electromagnetic lenses, vacuum chamber, detectors, and sample stage. SEMs produce high-resolution images of sample surfaces by scanning them with a focused beam of electrons. Signals produced by electron-sample interactions reveal information about morphology, composition, and structure. Applications of SEMs discussed include nanomaterial characterization, archaeology, biology, and industrial quality control. Limitations include sample size constraints and specialized training required.
IEEE Student Branch Chittagong University arranged a webinar titled "From APECE to ASML A Semiconductor Journey". Shawn Millat shared his working experience in Semiconductor industry and also shared tips about studying in Germany.
Tunneling electron Microscopy, Scanning electron microscopyelminehtsegahun2
- The document discusses transmission electron microscopy (TEM), providing details about its essential parts, operation principles, imaging modes, diffraction techniques, and applications.
- TEM uses electron beams to image nanoscale structures, with key components including an electron gun, condenser lenses, specimen holder, objective lens, and viewing screen. Specimens must be very thin to transmit electrons.
- Imaging modes include bright field, dark field, and high resolution, which produce different image contrasts. Diffraction techniques like selected area diffraction are also described.
- Applications involve characterizing materials structures, layers, interfaces, and chemical composition at the nanoscale. TEM provides both imaging and diffraction/crystallographic information
1) CONTENTS:
Introduction
Construction
Working Principle
The Electron Gun And Condenser System
Image Producing & Recording System
TEM Applications
Advantages
Disadvantages
2) INTRODUCTION:
A Transmission Electron Microscope (TEM) utilizes energetic electron beam to provide morphologic, compositional and crystallographic information on samples.TEM produce High-Resolution, 2D images. The first transmission electron microscope was invented in 1933 by Max Knoll and E. Ruska at the Technical College in Berlin.
3) CONSTRUCTION:
Electron Gun – to produce electrons.
Magnetic condensing lens - to condense the electrons and to adjust the spot size of the electron.The specimen is placed in between the condensing lens and the objective lens.
The magnetic objective lens - to block the high angle diffracted
beam.
Aperture - eliminate the diffracted beam (if any) and in turn
increases the contrast of the image.The magnetic projector lens - to achieve higher magnification.
Fluorescent (Phosphor) screen – To record the image.
4)Working Principle: High voltage electron beam is transmitted through a specimen to form an image. Stream of electrons are produced by the electron gun and is made to fall over the specimen using the magnetic condensing lens.Electrons are made to pass through the specimen and the image is formed on the fluorescent screen.
5) The Electron Gun And Condenser System: The image can be manipulated by adjusting the voltage of the gun to accelerate or decrease the speed of electrons as well as changing the electromagnetic wavelength via the solenoids.
6) Image Producing & Recording System:
Air needs to be pumped out of the vacuum chamber, creating a
space where electrons are able to move.The objective lens is used to produces a image and then further magnified by the projector lens. The lighter areas of the image represent the places where a greater number of electrons were able to pass through the sample and the darker areas reflect the dense areas of the object. Monochromatic image is recorded in fluorescent screen or by capturing the image digitally to display on a computer monitor,basically stored in a TIFF or JPEG format.
7)TEM Applications:
It analyze structure, topographical, morphological, compositional and crystalline information. Can be used in semiconductor analysis and production and the manufacturing of computer and silicon chips. To identify fractures and damages.
8)Advantages:
Powerful magnification . It can produce magnification as high as 1,00,000 times as that of the size of the object.
Images are high-quality and detailed.They are easy to operate with proper training.
9)Disadvantages:
Large and very expensive.
Laborious sample preparation.
TEM require special housing and maintenance.
Samples are limited to those that are electron transparent.
10) Thank You
The document summarizes recent developments in optical and photonic technology at Zhejiang University's Department of Optical Engineering. It discusses research on micro- and nano-fibers, photonic crystals, optical thin film devices, and their applications. The department has grown to become a leading institution in China for optical engineering education and research, with over 98 faculty/staff members and extensive funding for projects.
Pollen photos using a Scanning Electron MicroscopeChris Cardew
The document compares the scanning electron microscope (SEM) to the light microscope. It states that the SEM can achieve much higher magnifications than the light microscope, up to 500,000x compared to 1000-1500x, because electrons have a much shorter wavelength than visible light. This allows the SEM to achieve much higher resolving power and see finer detail, around 4nm, versus around 200nm for the light microscope. It also notes some key differences in their operation, such as the SEM using electrons rather than visible light and requiring a vacuum rather than air-filled interior.
This document provides an overview of microscopy including:
1. It outlines the historical development of the microscope from the 1500s to present.
2. It describes key microscope components and variables like magnification, resolution, numerical aperture, aberration, and contrast.
3. It explains different microscope types like compound light, darkfield, phase contrast, fluorescence, electron, confocal, and scanning probe microscopes as well as their principles and uses.
4. It provides guidance on microscope care and proper storage, handling of lenses, and care of oil emersion objectives and lamps.
This document provides an overview of various nanoscale imaging tools, including optical microscopes, electron microscopes like transmission electron microscopes and scanning electron microscopes, and scanning probe microscopes like scanning tunneling microscopes and atomic force microscopes. It describes key parameters, components, imaging modes and examples of images produced by these different microscopic techniques.
The document describes Nanonics Imaging Ltd's Nanonics Optometronic 4000 system, which provides an integrated platform for optical, electrical, and thermal characterization at the micro and nanoscale. The system uniquely combines atomic force microscopy (AFM) with near-field scanning optical microscopy (NSOM) using specialized fiber optic probes. This allows for correlated structural and optical measurements in the near and far field. The system is positioned to be a leading platform for photonics characterization in the 21st century, known as the Century of Photonics.
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16. Thank you: stay tuned.
Trevor
FOWLER,
Laurent
MOREAUX,
Eran
SEGEV,
Derrick
CHI,
Michael
ROUKES,
Andrei
FARAON,
Caltech Team
Collaborators:
Wesley
Sacher
,
Baylor Collage
Andreas Tolias
Jacob Raimer
Stanford
Karl Deisseroth
Maisie Lo
U. Toronto
Joyce Poon
Editor's Notes
Hello, and thank you for joining my talk.
Today I’m going to talk about our effort to develop fine light projection tools for deep-brain optogenetic stimulation.
Such tools should fulfill the following requirements:
First we are talking about implantable probes because free –space microscope based methods can only address superficial layers of the brain. These probes should cause minimal brain perturbation, so they should be minimal both in size and in the amount of heat they deliver to the brain.
Second in order to project complex illumination pattern they should have many densely packed emitting pixels, and more importantly each of those should be individually addressed and controlled.
Finally, We would like to develop a technology which is scalable and mass-producible so we would be able to produce affordable probes to the entire neural community.
Our objective is that the technology of visible silicon photonic is the only onethat can address all of those needs.
The mechanical structure of our probes is made of silicon. As such the entire toolbox of MEMS fabrication techniques can be used to fabricate these probes.
This means that there is a lot of flexibility in the design of the shape of these probes, which can be tailored for the specific needs of a specific experiment. Some examples for various possible shapes are shown in those pictures. …..
What’s even more important is the ability to miniaturize these probes. On the left you can see an image comparing the width of the top section of the shanks to the width of a regular single-mode fiber. Multimode fibers are usually even wider than that. On the bottom left you can see a side view of the probe. Using MEMS fabrication techniques we managed to fabricate shanks only 20 um in thickness, through out the length of the shank. The image on the right shows how smaller is this cross-section compared again to a regular optical fiver.
The photonic circuitry of our probes is patterned in a thin layer of silicon nitride encapsulated by silicon oxide. .
We use grating couplers for coupling the light from an optical fiber to the chip. We have waveguides that deliver the light across the chip, and we have another set of grating couplers that function as photonic emitters that project the light out of the probe and into the brain.
The major problem, however, is how to drive, and individually control each of the multiple illumination points located on this probe. Obviously, driving each of those E-pixels using a dedicated optical fiber is not a scalable solution.
Optical communication has solved this problem many years ago by developing all sorts of multiplexing techniques. From those we choose to implement the WDM technique because it is in particular suitable for our needs.
The reason for that is the following:
The response curves of optogenetic actuators usually have rather broad spectrum. Therefore we can use a variety of wavelengths to excite these opsins, and a single optical fiber can couple all those wavelength to the chip. An AWG that is implemented on the chip routes each color to its destination E-pixel, and thus crease a 1:1 mapping between the wavelength of the light and the spatial location where it is emitted.
Finally, we can use external hardware like AO filter to switch between different combination of colors and thus control the exact temporal-spatial illumination pattern.
This slide show few SEM images of the AWG’s we’ve prototyped. These are very compact AWG’s, and integrate one at the base of each shank. The graph on the right shows a typical spectral measurement or our AWG’s. Typical channel spacing is 1nm, and we get about 10dB xtalk ratio.
In our prototype devices each AWG drives 9 E-pixels. The spacing between these E-pixels was 200um in our first generation, and went down to 100um in the current generation. Our future probes that are planed to be fabricated in photonic foundries will be designed to have pitch smaller than 50um between E-pixels.
Such dense array of emitters is possible due to the almost collimated beam shape of the light emitted by the E-pixels.
Let me explain why is that important. Consider a probe emitting wide beam shape, which is typically the case when using LEDs as light sources. This would have two drawbacks. First, the intensity of the beam quickly drops. In addition, the illuminated beams patterns overlaps, and thus the illumination generated by adjacent E-pixles is not really independent, even if they are individually controlled. We have to keep the illumination beam really narrow in order to avoid such overlaps.
This is exactly the case in our photonic probes.
The following image shows side view of one of our photonic probes soaked in fluorescein solution. As you can see the probe illuminates highly directional beam almost perpendicular to its surface. The FWHM of the beam is only about 18 200 um away from the probe. This width is about the order of a neural cell body.
Scattering of the light in the mouse brain slightly expends the beam, but because this scattering is mostly forward scattering the FWHM beam width is still only 25um at 200 um away from the probe.
Simulation results, which do not include any scattering shows that the fundamental width of the beam grows to only 30um at a distance of 1mm away from the probe. As you can see in the image above, is stays rather collimated for longer distances as well.
The in-plane illumination angle of the beam is a design parameter controlled by the period of the grating couplers. These simulation results show that we can change the illumination angleof the beam without any major impact on its divergence angle.
Going back to multi-pixel light projection, this image shows several E-pixels illuminating simultaneously. These are first generation probes with a pitch of 200um between E-pixels. You can imagine how these can be made much denser without causing overlaps between beams.
The movie I’m about to show demonstrate how we address different pixels by manually change the input wavelength to the AWG.
The first method was direct electrical measurements of the neural activation generated by our probes.
The following picture shows the method by which this was done. First a Tungsten electrode was glued on top of the probes. The tip of the electrode was places close to the trajectory of the illumination beam. These coupled probes were implanted into the CA3 brain area of Thy1 transgenic mice.
The graph on the right show the raster
Using this flat packaging we are able to easily get under the microscope objective during in vivo experiments.