interference lithography
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Four-beam interference lithography can be used to rapidly fabricate micro-lens arrays. The shape of the micro-lenses depends on laser processing parameters such as average power and irradiation time. Higher laser power or longer exposure time results in larger diameter micro-lenses due to increased photopolymerization. A model is proposed that relates laser intensity, exposure time, and periodic intensity distribution to the diameter of the fabricated micro-lenses.
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![Mechanism of micro-lens array formation by using four-beam
interference lithography
E. Stankevicius, M. Gedvilas, M. Garliauskas, G. Raciukaitis
Center for Physical Sciences and Technology (CPST), Savanoriu av. 231, LT-02300 Vilnius, Lithuania
e-mail: estankevicius@ar.fi.lt
Photo-polymerization processes induced by ultra-short pulsed lasers [1-3] have drawn a lot of
attention in the past few years due to its precision and flexibility. The higher process efficiency can be
achieved by the parallel processing technique using interference of several laser beams [4-7]. Depends
on the interfering beams parameters (phase, angle between beams, number of beams, used
wavelengths, etc) [6] different types of micro-structures are possible to form. Micro-structures
fabricated by four-beam interference lithography have shape of the micro-pillar array [8]. The shape
of fabricated micro-pillars strongly depends on the laser irradiation dose [6]. Top of the micro-pillars
in a single-photon excitation case have a spherical shape, acting as micro-lenses (Fig. 1).
Fig. 1 Micro-lenses fabricated by interference lithography by using the same exposure time (30 s) and different laser average power:
a) ~ 470 mW, b) ~ 630 mW and c) ~ 930 mW. The distance between micro-lenses is ~ 60 µm. Laser processing parameters are: wavelength
- 515 nm, repetition rate - 100 kHz. SEM images of the structures are tilted by 34 deg.
Here, we will introduce rapid and flexible micro-lens array fabrication method by using four-beam
interference lithography and a single-photon excitation technique. Also we will analyze the influence
of the laser processing parameters (the average laser power and the irradiation time) to the shape of
these micro-lenses and propose a model which explicitly treats the close relationship between the
laser intensity, the irradiation time, period of intensity distribution and the diameter of the fabricated
micro-lens. The proposed model is in good agreement with the experimental results and explains the
mechanism of micro-lens formation.
[1] S. Maruo, O. Nakamura and S. Kawata, "Three-dimensional microfabrication with two-photon-absorbed photopolymerization",
Opt. Lett. 22, 132-134, 1997.
[2] J. Serbin, A. Egbert, A. Ostendorf, B. N. Chichkov, R. Houbertz, G. Domann, J. Schulz, C. Cronauer, L. Fröhlich and M. Popall,
"Femtosecond laser-induced two-photon polymerization of inorganic organic hybrid materials for applications in photonics",
Opt. Lett. 28, 301-303, 2003.
[3] R. Guo, S. Xiao, X. Zhai, J. Li, A. Xia and W. Huang, "Micro lens fabrication by means of femtosecond two photon
photopolymerization", Opt. Express 14, 810-816, 2006.
[4] M. Campbell, D. N. Sharp, M. T. Harrison, R. G. Denning and A. J. Turberfield, "Fabrication of photonic crystals for the visible
spectrum by holographic lithography", Nature 404, 53-56, 2000.
[5] T. Kondo, S. Matsuo, S. Juodkazis and H. Misawa, "Femtosecond laser interference technique with diffractive beam splitter for
fabrication of three-dimensional photonic crystals", Appl. Phys. Lett. 79, 725-727, 2001.
[6] E. Stankevicius, M. Gedvilas, B. Voisiat, M. Malinauskas and G. Raciukaitis, "Fabrication of periodic micro-structures by
holographic lithography", Lith. J. Phys. 53, 227-237, 2013.
[7] H. Misawa, T. Kondo, S. Juodkazis, V. Mizeikis and S. Matsuo, "Holographic lithography of periodic two- and three-
dimensional microstructures in photoresist SU-8", Opt. Express 14, 7943-7953, 2006.
[8] E. Stankevicius, M. Malinauskas, M. Gedvilas, B. Voisiat and G. Raciukaitis, "Fabrication of periodic micro-structures by multi-
photon polymerization using the femtosecond laser and four-beam interference", Mat. Sci. (Medžiagotyra) 17, 244-248, 2011.
a) b) c)](https://image.slidesharecdn.com/e-150515111436-lva1-app6891/85/interference-lithography-1-320.jpg)
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This document discusses metamaterials and their applications in superlensing and cloaking. It begins by explaining Victor Veselago's proposal in the 1960s that a material with negative permeability and permittivity could bend light backwards. In the 2000s, Pendry and Smith created metamaterials with engineered electromagnetic responses at subwavelength scales that demonstrated negative refraction. This led to the development of the superlens, which can overcome the diffraction limit and image objects smaller than the wavelength of light used. The document also discusses how transformation optics allows for the design of cloaking materials that bend light around objects, rendering them invisible.
Vitality of Physics In Nanoscience and Nanotechnology
This document discusses the vital role of physics in nanoscience and nanotechnology. It explains that at the nanoscale, physics is different due to quantum effects and a high surface area to volume ratio. Properties like band structure and optical properties can be altered at the nanoscale. The document also discusses manufacturing approaches like top-down and bottom-up methods and how they apply physics principles to create nanomaterials. Finally, it notes that nanomaterials can have significantly different properties than bulk materials of the same composition due to their small size and large surface area.
Fibre optic sensors and smart composites for
Fibre-optic sensors and smart composites have potential applications for monitoring the structural health of concrete structures. Fibre-optic sensors can be embedded in fibre-reinforced polymer (FRP) composites used to strengthen concrete. This allows the composite to both reinforce the structure and monitor it in real-time. Optical fibres can measure strain and temperature with high accuracy and resolution without impacting the mechanical properties of the structure. The development of distributed fibre sensors provides continuous monitoring along the length of the structure.
Image Reduction Programs for Non-Circular Core Fiber Scrambler
This document summarizes work analyzing data from observations of exoplanets using different shaped optical fibers. Code was developed to reduce images and plot line spread functions to determine which fiber most evenly scrambles starlight. Data from 2012 observations were analyzed for various star targets using 200um octagonal, 50um octagonal, rectangular, and square core fibers of 1m and 10m lengths. Standard deviations were calculated and some fibers showed consistency down to 1-2% while others ranged as high as 30%. The 50um octagonal fiber data on December 10th had the highest standard deviation of 16.89%.
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1. The document summarizes Tijmen G. Euser's research activities and publications. As a PhD student, he studied dynamic changes in light propagation in photonic crystals and demonstrated optical switching of photonic band gap crystals.
2. As a postdoc, his research included developing hollow-core photonic crystal fibers for optofluidic microreactors, waveguide-based micromanipulation techniques, and spatial light modulation applications. This work enabled new experiments in fields like photochemistry, microparticle transport, and fiber-based spectroscopy.
3. His publications include over 40 peer-reviewed papers investigating topics like optofluidic reactors, optical trapping and propulsion in fibers, spatial mode control
CV Christopher Shearwood July-2016
This curriculum vitae summarizes the educational and professional experience of Christopher Shearwood. He received a PhD in Solid State Physics from the University of Leeds in 1988. Since 1998, he has been an Associate Professor at Nanyang Technological University where he teaches and conducts research related to materials science and engineering. He has over 40 publications and 2 patents related to his work developing microelectromechanical systems and studying materials properties.
3 d molding and casting4
This document describes a simple method for fabricating plastic microlens arrays with controllable shape and high fill-factor using 3D diffuser lithography and plastic replication. A diffuser is inserted into the conventional lithography process to randomize the UV light paths and form lens-like 3D latent images in thick photoresist. Microlens molds are then replicated by casting liquid PDMS onto the photoresist patterns. The focal length of the fabricated hemispherical microlenses ranges from 13-88 μm depending on UV exposure dose. Curing PDMS at 85°C produces smoother molds with surface roughness of 2.6 nm compared to room temperature curing.
An Research Article on Fabrication and Characterization of Nickel Oxide Coate...
In this paper we have produced NiO thin film based solar cells. The NiO thin film was then studied for their structural, optical and electrical properties. By the help of these results we have capable to know about the structure of NiO the phase purity of the thin film X ray diffraction XRD pattern of NiO showed the diffraction planes corresponding to cubic phase respectively. The optical properties showed that with the increase in the deposition time of NiO the energy band gap varied between 3.1 to 3.24 eV. In the end, IV characteristics of the thin films were obtained by the help of matlab in the presence of light as will as dark region. Vijay Aithekar "An Research Article on Fabrication and Characterization of Nickel Oxide Coated Solar Cell" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-5 , August 2019, URL: https://www.ijtsrd.com/papers/ijtsrd25300.pdfPaper URL: https://www.ijtsrd.com/physics/nanotechnology/25300/an-research-article-on-fabrication-and-characterization-of-nickel-oxide-coated-solar-cell/vijay-aithekar
Mason - Modelling radiation damage in cellular systems
This project will develop a model for simulating radiation damage in cellular systems using MBN Explorer software. The model will study interactions between radiation (X-rays or ions) and biological components (DNA, proteins, etc.) to identify which biomolecular bonds are most susceptible to damage. In collaboration with other PhD students, the model may then explore how different radiosensitizers induce bond breaks, leading to cell death and improved radiotherapy. The student will spend time training with MBN Explorer in Frankfurt and will have opportunities to collaborate across physics, chemistry, biology, medicine, and business on radiation damage topics.
ENERGY GAP INVESTIGATION AND CHARACTERIZATION OF KESTERITE CU2ZNSNS4 THIN FIL...
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Solar cell absorber Kesterite- type Cu2ZnSnS4 (CZTS) thin films have been prepared by Chemical Bath Deposition (CBD). UV–vis absorption spectra measurement indicated that the band gap of as-synthesized CZTS was about1.68 eV, which was near the optimum value for photovoltaic solar conversion in a single-band-gap device. The polycrystalline CZTS thin films with kieserite crystal structure have been obtained by XRD. The average of crystalline size of CZTS is 27 nmDevelopment of spiral square coils for magnetic labelling detection in microf...
Due to the development of microfluidic systems biomedical microelectromechanical systems (BioMEMS) for magnetic labelling detection by magnetic microbeads circling in microfluidic channels, we used the magnetic field created by microcoils. The magnetic field associated with the electric current, but with negatively affects if its value increases too much. Handling bio-species in the microfluidic chip requires that the temperature maintained to keep the cells to prevent their destruction. In this paper we have described the spiral square coil design of different structures to produce an effective magnetic flux density. The simulation of the magnetic flux density is carried out with the help of the COMSOL software. We have presented an optimization of the geometric parameters of the microcoil for a better performance and a miniaturization of the structure with copper wire section S=25 µm2 and inter-wire space a=5 µm. We have also developed this microcoil by adding a ferromagnetic core to the inner center, the results obtained in this work shown that the magnetic flux density increases around 1.07 times in Bx and 1.45 times in Bz. This new approach in designing a microcoil allows to obtaining a fast trapping of the microbeads and a highly sensitive biological element detection and avoiding increase heat ratio in microfluidic systems.
A
This document discusses non-line-of-sight (NLOS) free space optical (FSO) communication systems using infrared lasers. It first reviews previous work using ultraviolet lasers and the limitations of those models. The research objective is then presented as proposing an infrared-based NLOS geometrical model using optical reflectors and analyzing generic system performance metrics.
Final Poster
This document summarizes work done to develop a photolithography process for fabricating microscale structures on quartz crystals. The structures will be used to study friction at the microscale using a nanoindenter and quartz crystal microbalance. The process involves cleaning the crystals, spinning on photoresist, exposing the photoresist to UV light through a photomask, developing the structures, and hard baking them. The authors optimized the exposure time, development time, and photoresist coating parameters to produce structures with straight edges for future friction experiments exploring the effects of contact size, speed, material, and thin films.
Nanotechnology.pptx
Introduction of Nanotechnology
Applications of Nano technology
Scanning Electron Microscope
Principle
Construction
Working
Advantages
Dis-Advantages
Conclusion
References
W03301330140
International Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity.
Plasmonic wave assessment via optomechatronics system for biosensor application
Transduction biosensor (mass-based, optical and electrochemical) involves analysis, recognition and amplification in the acquired sample. In this work, the plasmonic-based biosensor was employed without using tags. It is crucial to determine angles of Brewster (Ɵb) and critical (Ɵc) for generating plasmonic resonance (Ɵr). The objective is to verify a cost-effective plasmonic biosensor through Fresnel simulation and experimentation of a developed optomechatronics system. The borosilicate glass, Au and Air layers were simulated with the Winspall 3.02 simulator. The optomechatronics system consists of: 1-optics (650 nm laser, slit, polarizer, photodiode), 2-mechanical (bipolar stepper motors, gears, stages) and 3-electronics (PIC18F4550, liquid crystal display (LCD) and drivers). Later, the software performs angular interrogation by reading the reflected beam from a rotating prism at 0.1125. Experimentation to simulation accuracy indicates that percentage differences for Ɵr and Ɵc are 1% and 0.2%, respectively. In conclusion, excellence verification was successfully achieved between experimentation and simulation. It proved that the lowcost optomechatronics system is capable and reliable to be deployed for the biosensor application.
Structural and Surface Morphology Studies of Zinc Sulphide Nanopowders
This document discusses the structural and morphological analysis of zinc sulfide (ZnS) nanopowders prepared by the control precipitation method. X-ray diffraction and scanning electron microscopy were used to analyze the nanopowders. XRD analysis showed the nanopowders were polycrystalline with a cubic crystal structure. The average grain size was determined to be around 20nm using the Scherrer formula. SEM images revealed the nanopowders had a non-uniform morphology and grain size distribution. The nanopowders properties make them promising for applications in optoelectronics and electronics.
IRJET- Optical Steering of Microbubbles for Nanoparticle Transport
The document summarizes research on optically manipulating microbubbles and microbubbles coated with metallic nanoparticles. It begins with developing a theoretical model for the optical force on a microbubble in a laser beam based on induced dipoles. Experiments show microbubbles of different sizes are attracted to the laser beam center. The model is extended to microbubbles coated with nanoparticles, and experiments show nanoparticles have a negligible effect on manipulation. Optical steering of nanoparticle-surrounded microbubbles is demonstrated and could enable targeted drug delivery.
A010320107
This document discusses the design of a fiber optic security sensor based on monitoring speckle patterns in multimode optical fibers. The sensor is designed to detect vibrations on perimeters or fences by observing changes in the output speckle pattern from the fiber. An experimental model was built using readily available components - a CCD camera, multimode laser light source, length of optical fiber, and MATLAB software. The sensor is low-cost, lightweight, and can potentially be used to monitor large structures. When disturbances occur on the fiber, it causes changes in the propagation constants of fiber modes, altering the output speckle pattern in a way that can be analyzed to detect vibrations.
Andrii Sofiienko - Electron range evaluation and X-ray conversion optimizatio...
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This document discusses advances in laser holographic lithography techniques for fabricating 3D nanostructures. It describes how holographic lithography can be achieved using a single optical element such as a diffractive phase mask or deflective prism. Specifically, it provides examples of using a 2D phase mask and a 4-sided prism to generate interference patterns that can produce diamond-like 3D photonic crystal structures in a single laser exposure, overcoming limitations of previous multi-element approaches. Controlling the phase of laser beams is shown to be crucial for enabling the fabrication of complex 3D structures using these single-element holographic lithography methods.
OpticsExpress_Afshin
This document discusses the transfer of micro and nano-photonic silicon nanomembrane waveguide devices onto flexible substrates. It demonstrates transferring optical devices without extra un-patterned silicon onto low-cost, flexible plastic substrates using single-crystal silicon nanomembranes. Specifically, it shows stacking two layers of silicon nanomembranes, with a photonic crystal waveguide in the first layer and multi-mode interference couplers in the second layer, respectively, onto a flexible substrate. This technique promises high density integration of multilayer hybrid structures on flexible substrates.
Synthesis and characterization of zno thin films deposited by chemical bath t...
Abstract ZnO thin films have been deposited on silica glass substrate using the chemical bath deposition technique. The precursors used were zinc chloride and aqueous ammonia. The solution was stirred continuously with the help of a magnetic stirrer at a bath temperature of 70 oC and a deposition time of 70 minutes. The elemental composition and the surface morphology were studied using energy dispersive and scanning electron microscopy. The band gap was 2.72, 2.66, 2.60 eV for as-deposited, annealed at 200 oC and 300 oC respectively. There was a red shift in the band gap energy as the annealing temperature was increased. This might be due to an improvement in the crystallinity of the ZnO thin films. Index Terms: Zinc oxide, chemical bath, band gap, annealing
Synthesis and characterization of zno thin films
The document summarizes the synthesis and characterization of ZnO thin films deposited by chemical bath deposition technique. ZnO thin films were deposited on silica glass substrates in a chemical bath containing zinc chloride and ammonia at 70°C for 70 minutes. Elemental composition analysis using EDAX confirmed the formation of ZnO. SEM images showed the films had a nanorod morphology. The band gap was determined to be 2.72 eV for the as-deposited film and decreased to 2.66 eV and 2.60 eV for films annealed at 200°C and 300°C, respectively, due to improved crystallinity.
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Plasmonic wave assessment via optomechatronics system for biosensor application
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Structural and Surface Morphology Studies of Zinc Sulphide Nanopowders
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IRJET- Optical Steering of Microbubbles for Nanoparticle Transport
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Mending Clothing to Support Sustainable Fashion_CIMaR 2024.pdf
Ozturkcan, S., Berndt, A., & Angelakis, A. (2024). Mending clothing to support sustainable fashion. Presented at the 31st Annual Conference by the Consortium for International Marketing Research (CIMaR), 10-13 Jun 2024, University of Gävle, Sweden.
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Classification
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Complex titration with EDTA.
The debris of the ‘last major merger’ is dynamically young
The Milky Way’s (MW) inner stellar halo contains an [Fe/H]-rich component with highly eccentric orbits, often referred to as the
‘last major merger.’ Hypotheses for the origin of this component include Gaia-Sausage/Enceladus (GSE), where the progenitor
collided with the MW proto-disc 8–11 Gyr ago, and the Virgo Radial Merger (VRM), where the progenitor collided with the
MW disc within the last 3 Gyr. These two scenarios make different predictions about observable structure in local phase space,
because the morphology of debris depends on how long it has had to phase mix. The recently identified phase-space folds in Gaia
DR3 have positive caustic velocities, making them fundamentally different than the phase-mixed chevrons found in simulations
at late times. Roughly 20 per cent of the stars in the prograde local stellar halo are associated with the observed caustics. Based
on a simple phase-mixing model, the observed number of caustics are consistent with a merger that occurred 1–2 Gyr ago.
We also compare the observed phase-space distribution to FIRE-2 Latte simulations of GSE-like mergers, using a quantitative
measurement of phase mixing (2D causticality). The observed local phase-space distribution best matches the simulated data
1–2 Gyr after collision, and certainly not later than 3 Gyr. This is further evidence that the progenitor of the ‘last major merger’
did not collide with the MW proto-disc at early times, as is thought for the GSE, but instead collided with the MW disc within
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Title: Gravitational wave detection with orbital motion of Moon and artificial
Abstract:
In this talk I will describe some recent ideas to find gravitational waves from supermassive black holes or of primordial origin by studying their secular effect on the orbital motion of the Moon or satellites that are laser ranged.EWOCS-I: The catalog of X-ray sources in Westerlund 1 from the Extended Weste...
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represent the most massive star-forming environment that is dominated by the feedback from massive stars and gravitational interactions
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The primary targets of this project are Westerlund 1 and 2, the closest supermassive star clusters to the Sun.
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photon flux threshold of approximately 2 × 10−8 photons cm−2
s
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With increasing population, people need to rely on packaged food stuffs. Packaging of food materials requires the preservation of food. There are various methods for the treatment of food to preserve them and irradiation treatment of food is one of them. It is the most common and the most harmless method for the food preservation as it does not alter the necessary micronutrients of food materials. Although irradiated food doesn’t cause any harm to the human health but still the quality assessment of food is required to provide consumers with necessary information about the food. ESR spectroscopy is the most sophisticated way to investigate the quality of the food and the free radicals induced during the processing of the food. ESR spin trapping technique is useful for the detection of highly unstable radicals in the food. The antioxidant capability of liquid food and beverages in mainly performed by spin trapping technique.
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Equivariant neural networks and representation theory
Or: Beyond linear.
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Disclaimer: No one is perfect, so please mind that there might be mistakes and typos.
dtubbenhauer@gmail.com
Corrected slides: dtubbenhauer.com/talks.html
waterlessdyeingtechnolgyusing carbon dioxide chemicalspdf
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When I was asked to give a companion lecture in support of ‘The Philosophy of Science’ (https://shorturl.at/4pUXz) I decided not to walk through the detail of the many methodologies in order of use. Instead, I chose to employ a long standing, and ongoing, scientific development as an exemplar. And so, I chose the ever evolving story of Thermodynamics as a scientific investigation at its best.
Conducted over a period of >200 years, Thermodynamics R&D, and application, benefitted from the highest levels of professionalism, collaboration, and technical thoroughness. New layers of application, methodology, and practice were made possible by the progressive advance of technology. In turn, this has seen measurement and modelling accuracy continually improved at a micro and macro level.
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interference lithography
- 1. Mechanism of micro-lens array formation by using four-beam interference lithography E. Stankevicius, M. Gedvilas, M. Garliauskas, G. Raciukaitis Center for Physical Sciences and Technology (CPST), Savanoriu av. 231, LT-02300 Vilnius, Lithuania e-mail: estankevicius@ar.fi.lt Photo-polymerization processes induced by ultra-short pulsed lasers [1-3] have drawn a lot of attention in the past few years due to its precision and flexibility. The higher process efficiency can be achieved by the parallel processing technique using interference of several laser beams [4-7]. Depends on the interfering beams parameters (phase, angle between beams, number of beams, used wavelengths, etc) [6] different types of micro-structures are possible to form. Micro-structures fabricated by four-beam interference lithography have shape of the micro-pillar array [8]. The shape of fabricated micro-pillars strongly depends on the laser irradiation dose [6]. Top of the micro-pillars in a single-photon excitation case have a spherical shape, acting as micro-lenses (Fig. 1). Fig. 1 Micro-lenses fabricated by interference lithography by using the same exposure time (30 s) and different laser average power: a) ~ 470 mW, b) ~ 630 mW and c) ~ 930 mW. The distance between micro-lenses is ~ 60 µm. Laser processing parameters are: wavelength - 515 nm, repetition rate - 100 kHz. SEM images of the structures are tilted by 34 deg. Here, we will introduce rapid and flexible micro-lens array fabrication method by using four-beam interference lithography and a single-photon excitation technique. Also we will analyze the influence of the laser processing parameters (the average laser power and the irradiation time) to the shape of these micro-lenses and propose a model which explicitly treats the close relationship between the laser intensity, the irradiation time, period of intensity distribution and the diameter of the fabricated micro-lens. The proposed model is in good agreement with the experimental results and explains the mechanism of micro-lens formation. [1] S. Maruo, O. Nakamura and S. Kawata, "Three-dimensional microfabrication with two-photon-absorbed photopolymerization", Opt. Lett. 22, 132-134, 1997. [2] J. Serbin, A. Egbert, A. Ostendorf, B. N. Chichkov, R. Houbertz, G. Domann, J. Schulz, C. Cronauer, L. Fröhlich and M. Popall, "Femtosecond laser-induced two-photon polymerization of inorganic organic hybrid materials for applications in photonics", Opt. Lett. 28, 301-303, 2003. [3] R. Guo, S. Xiao, X. Zhai, J. Li, A. Xia and W. Huang, "Micro lens fabrication by means of femtosecond two photon photopolymerization", Opt. Express 14, 810-816, 2006. [4] M. Campbell, D. N. Sharp, M. T. Harrison, R. G. Denning and A. J. Turberfield, "Fabrication of photonic crystals for the visible spectrum by holographic lithography", Nature 404, 53-56, 2000. [5] T. Kondo, S. Matsuo, S. Juodkazis and H. Misawa, "Femtosecond laser interference technique with diffractive beam splitter for fabrication of three-dimensional photonic crystals", Appl. Phys. Lett. 79, 725-727, 2001. [6] E. Stankevicius, M. Gedvilas, B. Voisiat, M. Malinauskas and G. Raciukaitis, "Fabrication of periodic micro-structures by holographic lithography", Lith. J. Phys. 53, 227-237, 2013. [7] H. Misawa, T. Kondo, S. Juodkazis, V. Mizeikis and S. Matsuo, "Holographic lithography of periodic two- and three- dimensional microstructures in photoresist SU-8", Opt. Express 14, 7943-7953, 2006. [8] E. Stankevicius, M. Malinauskas, M. Gedvilas, B. Voisiat and G. Raciukaitis, "Fabrication of periodic micro-structures by multi- photon polymerization using the femtosecond laser and four-beam interference", Mat. Sci. (Medžiagotyra) 17, 244-248, 2011. a) b) c)