H. Omran, Y. Sabry, Mohamed Sadek, Khaled Hassan, M. Shalaby, D. Khalil
We report a MEMS optical tunable filter based on high-aspect-ratio etching of sub-wavelength silicon layers on a silicon- on-insulator wafer. The reported filter has measured free-spectral and filter-tuning ranges of approximately 100 nm and a finesse of about 20 around a wavelength of 1550 nm, enabled by the use of 1000 nm-thick silicon layers and a balanced tilt-free motion using a lithographically-aligned electrostatic actuator. The average insertion loss of the filter is about 12 dB with a superior wavelength-dependent loss of about 1.5 dB. The filter has an out-of-band to in-band wavelength rejection ratio that is better than 20 dB. The reported filter experimental characteristics and its integrability are suitable for the production of integrated swept sources for optical coherence tomography application and miniaturized spectrometers.
{"title":"MEMS optical tunable filter based on free-standing subwavelength silicon layers","authors":"H. Omran, Y. Sabry, Mohamed Sadek, Khaled Hassan, M. Shalaby, D. Khalil","doi":"10.1117/12.2040767","DOIUrl":"https://doi.org/10.1117/12.2040767","url":null,"abstract":"We report a MEMS optical tunable filter based on high-aspect-ratio etching of sub-wavelength silicon layers on a silicon- on-insulator wafer. The reported filter has measured free-spectral and filter-tuning ranges of approximately 100 nm and a finesse of about 20 around a wavelength of 1550 nm, enabled by the use of 1000 nm-thick silicon layers and a balanced tilt-free motion using a lithographically-aligned electrostatic actuator. The average insertion loss of the filter is about 12 dB with a superior wavelength-dependent loss of about 1.5 dB. The filter has an out-of-band to in-band wavelength rejection ratio that is better than 20 dB. The reported filter experimental characteristics and its integrability are suitable for the production of integrated swept sources for optical coherence tomography application and miniaturized spectrometers.","PeriodicalId":395835,"journal":{"name":"Photonics West - Micro and Nano Fabricated Electromechanical and Optical Components","volume":"111 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132703748","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this work we present a new type of optical strain sensor that can be manufactured by MEMS typical processes such as photolithography or by hot embossing. Such sensors can be of interest for a range of new applications in structural health monitoring for buildings and aircraft, process control and life science. The approach aims at high sensitivity and dynamic range for 1D and 2D sensing of mechanical strain and can also be extended to quantities such as pressure, force, and humidity. The sensor consists of an array of planar polymer-based multimode waveguides whose output light is guided through a measurement area and focused onto a second array of smaller detection waveguides by using micro-optical elements. Strain induced in the measurement area varies the distance between the two waveguide arrays, thus, changing the coupling efficiency. This, in turn, leads to a variation in output intensity or wavelength which is monitored. We performed extensive optical simulations in order to identify the optimal sensor layout with regard to either resolution or measurement range or both. Since the initial approach relies on manufacturing polymer waveguides with cross sections between 20×20 μm2 and 100×100 μm2 the simulations were carried out using raytracing models. For the readout of the sensor a simple fitting algorithm is proposed.
{"title":"Planar integrated polymer-based optical strain sensor","authors":"Christian Kelb, E. Reithmeier, B. Roth","doi":"10.1117/12.2037295","DOIUrl":"https://doi.org/10.1117/12.2037295","url":null,"abstract":"In this work we present a new type of optical strain sensor that can be manufactured by MEMS typical processes such as photolithography or by hot embossing. Such sensors can be of interest for a range of new applications in structural health monitoring for buildings and aircraft, process control and life science. The approach aims at high sensitivity and dynamic range for 1D and 2D sensing of mechanical strain and can also be extended to quantities such as pressure, force, and humidity. The sensor consists of an array of planar polymer-based multimode waveguides whose output light is guided through a measurement area and focused onto a second array of smaller detection waveguides by using micro-optical elements. Strain induced in the measurement area varies the distance between the two waveguide arrays, thus, changing the coupling efficiency. This, in turn, leads to a variation in output intensity or wavelength which is monitored. We performed extensive optical simulations in order to identify the optimal sensor layout with regard to either resolution or measurement range or both. Since the initial approach relies on manufacturing polymer waveguides with cross sections between 20×20 μm2 and 100×100 μm2 the simulations were carried out using raytracing models. For the readout of the sensor a simple fitting algorithm is proposed.","PeriodicalId":395835,"journal":{"name":"Photonics West - Micro and Nano Fabricated Electromechanical and Optical Components","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132714060","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The ability to design and develop 3D microstructures is important for microelectromechanical systems (MEMS) fabrication. Previous techniques used to create 3D devices included tedious steps in direct writing and aligning patterns onto a substrate followed by multiple photolithography steps using expensive, customized equipment. Additionally, these techniques restricted batch processing and placed limits on achievable shapes. Gray-scale lithography enables the fabrication of a variety of shapes using a single photolithography step followed by reactive ion etching (RIE). Micromachining 3D silicon structures for MEMS can be accomplished using gray-scale lithography along with dry anisotropic etching. In this study, we investigated: using MATLAB for mask designs; feasibility of using 1 μm Heidelberg mask maker to direct write patterns onto photoresist; using RIE processing to etch patterns into a silicon substrate; and the ability to tailor etch selectivity for precise fabrication. To determine etch rates and to obtain desired etch selectivity, parameters such as gas mixture, gas flow, and electrode power were studied. This process successfully demonstrates the ability to use gray-scale lithography and RIE for use in the study of micro-contacts. These results were used to produce a known engineered non-planer surface for testing micro-contacts. Surface structures are between 5 μm and 20 μm wide with varying depths and slopes based on mask design and etch rate selectivity. The engineered surfaces will provide more insight into contact geometries and failure modes of fixed-fixed micro-contacts.
{"title":"Fabrication of 3D surface structures using grayscale lithography","authors":"C. Stilson, R. Pal, R. Coutu","doi":"10.1117/12.2037361","DOIUrl":"https://doi.org/10.1117/12.2037361","url":null,"abstract":"The ability to design and develop 3D microstructures is important for microelectromechanical systems (MEMS) fabrication. Previous techniques used to create 3D devices included tedious steps in direct writing and aligning patterns onto a substrate followed by multiple photolithography steps using expensive, customized equipment. Additionally, these techniques restricted batch processing and placed limits on achievable shapes. Gray-scale lithography enables the fabrication of a variety of shapes using a single photolithography step followed by reactive ion etching (RIE). Micromachining 3D silicon structures for MEMS can be accomplished using gray-scale lithography along with dry anisotropic etching. In this study, we investigated: using MATLAB for mask designs; feasibility of using 1 μm Heidelberg mask maker to direct write patterns onto photoresist; using RIE processing to etch patterns into a silicon substrate; and the ability to tailor etch selectivity for precise fabrication. To determine etch rates and to obtain desired etch selectivity, parameters such as gas mixture, gas flow, and electrode power were studied. This process successfully demonstrates the ability to use gray-scale lithography and RIE for use in the study of micro-contacts. These results were used to produce a known engineered non-planer surface for testing micro-contacts. Surface structures are between 5 μm and 20 μm wide with varying depths and slopes based on mask design and etch rate selectivity. The engineered surfaces will provide more insight into contact geometries and failure modes of fixed-fixed micro-contacts.","PeriodicalId":395835,"journal":{"name":"Photonics West - Micro and Nano Fabricated Electromechanical and Optical Components","volume":"80 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124125101","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. Bandi, J. Baborowski, A. Dommann, H. Shea, F. Cardot, A. Neels
This work reports on irradiations made on silicon bulk-acoustic wave resonators. The resonators were based on a tuning fork geometry and actuated by a piezoelectric aluminum nitride layer. They had a resonance frequency of 150 kHz and a quality factor of about 20000 under vacuum. The susceptibility of the devices to radiation induced degradation was investigated using 60Co γ-rays and 50 MeV protons with space-relevant doses of up to 170 krad. The performance of the devices after irradiation indicated a high tolerance to both ionizing damage and displacement damage effects. The results support the efforts towards design and fabrication of highly reliable MEMS devices for space applications.
{"title":"Evaluation of silicon tuning-fork resonators under space-relevant radiation conditions","authors":"T. Bandi, J. Baborowski, A. Dommann, H. Shea, F. Cardot, A. Neels","doi":"10.1117/12.2044209","DOIUrl":"https://doi.org/10.1117/12.2044209","url":null,"abstract":"This work reports on irradiations made on silicon bulk-acoustic wave resonators. The resonators were based on a tuning fork geometry and actuated by a piezoelectric aluminum nitride layer. They had a resonance frequency of 150 kHz and a quality factor of about 20000 under vacuum. The susceptibility of the devices to radiation induced degradation was investigated using 60Co γ-rays and 50 MeV protons with space-relevant doses of up to 170 krad. The performance of the devices after irradiation indicated a high tolerance to both ionizing damage and displacement damage effects. The results support the efforts towards design and fabrication of highly reliable MEMS devices for space applications.","PeriodicalId":395835,"journal":{"name":"Photonics West - Micro and Nano Fabricated Electromechanical and Optical Components","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114570205","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yukinobu Nishio, K. Fujimura, S. Ogihara, M. Okano, S. Kitagawa
The micro lens array illumination device has an advantage on transmittance, but it also has the problem of the generation of diffraction pattern. Well-known method for reducing diffraction is adding randomness to array structure (random structure), but there are many choices to do it. In this study we examined the randomness with a scope that is realizable by diamond machining yet with good productivity. As the result, we have found that the diffraction pattern can be reduced sufficiently by adding randomness of some 10% of its lattice constant to spatial configuration of periodic lattice of micro lens array. In addition, we have also examined controlling the illuminance distribution, by taking advantage of high form accuracy which is special features of diamond machining.
{"title":"Random micro-lens array illumination device manufactured by ultra-precision machining","authors":"Yukinobu Nishio, K. Fujimura, S. Ogihara, M. Okano, S. Kitagawa","doi":"10.1117/12.2037486","DOIUrl":"https://doi.org/10.1117/12.2037486","url":null,"abstract":"The micro lens array illumination device has an advantage on transmittance, but it also has the problem of the generation of diffraction pattern. Well-known method for reducing diffraction is adding randomness to array structure (random structure), but there are many choices to do it. In this study we examined the randomness with a scope that is realizable by diamond machining yet with good productivity. As the result, we have found that the diffraction pattern can be reduced sufficiently by adding randomness of some 10% of its lattice constant to spatial configuration of periodic lattice of micro lens array. In addition, we have also examined controlling the illuminance distribution, by taking advantage of high form accuracy which is special features of diamond machining.","PeriodicalId":395835,"journal":{"name":"Photonics West - Micro and Nano Fabricated Electromechanical and Optical Components","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117125252","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The adoption of spectral imaging by industry has so far been limited due to the lack of high speed, low cost and compact spectral cameras. Moreover most state-of-the-art spectral cameras utilize some form of spatial or spectral scanning during acquisition, making them ill-suited for analyzing dynamic scenes containing movement. This paper introduces a novel snapshot multispectral imager concept based on optical filters monolithically integrated on top of a standard CMOS image sensor. It overcomes the problems mentioned for scanning applications by snapshot acquisition, where an entire multispectral data cube is sensed at one discrete point in time. This is enabled by depositing interference filters per pixel directly on a CMOS image sensor, extending the traditional Bayer color imaging concept to multi- or hyperspectral imaging without a need for dedicated fore-optics. The monolithic deposition leads to a high degree of design flexibility. This enables systems ranging from application-specific, high spatial resolution cameras with 1 to 4 spectral filters, to hyperspectral snapshot cameras at medium spatial resolutions and filters laid out in cells of 4x4 to 6x6 or more. Through the use of monolithically integrated optical filters it further retains the qualities of compactness, low cost and high acquisition speed, differentiating it from other snapshot spectral cameras.
{"title":"A compact snapshot multispectral imager with a monolithically integrated per-pixel filter mosaic","authors":"B. Geelen, N. Tack, A. Lambrechts","doi":"10.1117/12.2037607","DOIUrl":"https://doi.org/10.1117/12.2037607","url":null,"abstract":"The adoption of spectral imaging by industry has so far been limited due to the lack of high speed, low cost and compact spectral cameras. Moreover most state-of-the-art spectral cameras utilize some form of spatial or spectral scanning during acquisition, making them ill-suited for analyzing dynamic scenes containing movement. This paper introduces a novel snapshot multispectral imager concept based on optical filters monolithically integrated on top of a standard CMOS image sensor. It overcomes the problems mentioned for scanning applications by snapshot acquisition, where an entire multispectral data cube is sensed at one discrete point in time. This is enabled by depositing interference filters per pixel directly on a CMOS image sensor, extending the traditional Bayer color imaging concept to multi- or hyperspectral imaging without a need for dedicated fore-optics. The monolithic deposition leads to a high degree of design flexibility. This enables systems ranging from application-specific, high spatial resolution cameras with 1 to 4 spectral filters, to hyperspectral snapshot cameras at medium spatial resolutions and filters laid out in cells of 4x4 to 6x6 or more. Through the use of monolithically integrated optical filters it further retains the qualities of compactness, low cost and high acquisition speed, differentiating it from other snapshot spectral cameras.","PeriodicalId":395835,"journal":{"name":"Photonics West - Micro and Nano Fabricated Electromechanical and Optical Components","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121995123","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Haneveld, P. Tijssen, J. Oonk, M. Olde Riekerink, H. Tigelaar, R. van't Oever, M. Blom
A novel method for laser assisted room temperature bonding of two substrates is presented. The method enables the packaging of delicate (bio)structures and/or finished (MEMS) devices, as there is no need for a high temperature annealing process. This also allows the bonding of two substrates with non-matching thermal expansion coefficients. The basis of the presented technology is the ability to create a direct pre-bond between two substrates. These can be two glass substrates, of which one has a thin film metal coating (e.g. Cr. Ti, Ta, Au…), or a silicon-glass combination. After (aligned) pre-bonding of the two wafers, a laser (e.g. a Nd:YAG laser) is used to form a permanent bond line on the bond interface, using the metal layer as a light absorber (or the silicon, in the case of a glass-silicon combination). The permanent bond line width is in the order of 10-50μm. The use of a laser to form the permanent bond ensures a hermetic sealing of the total package; a distinctive advantage over other, more conventional methods of room temperature bonding (e.g. adhesive bonding). He-leak testing showed leak rates in the order of 10-9 mbar l/s. This meets the failure criteria of the MIL-STD-883H standard of 5x10-8 mbar l/s. An added functionality of the proposed method is the possibility to create electrical circuitry on the bond interface, using the laser to modify the metal interlayer, rendering it electrically non-conductive. Biocompatible packages are also possible, by choosing the appropriate interlayer material. This would allow for the fabrication of implantable packages.
{"title":"Laser assisted and hermetic room temperature bonding based on direct bonding technology","authors":"J. Haneveld, P. Tijssen, J. Oonk, M. Olde Riekerink, H. Tigelaar, R. van't Oever, M. Blom","doi":"10.1117/12.2040237","DOIUrl":"https://doi.org/10.1117/12.2040237","url":null,"abstract":"A novel method for laser assisted room temperature bonding of two substrates is presented. The method enables the packaging of delicate (bio)structures and/or finished (MEMS) devices, as there is no need for a high temperature annealing process. This also allows the bonding of two substrates with non-matching thermal expansion coefficients. The basis of the presented technology is the ability to create a direct pre-bond between two substrates. These can be two glass substrates, of which one has a thin film metal coating (e.g. Cr. Ti, Ta, Au…), or a silicon-glass combination. After (aligned) pre-bonding of the two wafers, a laser (e.g. a Nd:YAG laser) is used to form a permanent bond line on the bond interface, using the metal layer as a light absorber (or the silicon, in the case of a glass-silicon combination). The permanent bond line width is in the order of 10-50μm. The use of a laser to form the permanent bond ensures a hermetic sealing of the total package; a distinctive advantage over other, more conventional methods of room temperature bonding (e.g. adhesive bonding). He-leak testing showed leak rates in the order of 10-9 mbar l/s. This meets the failure criteria of the MIL-STD-883H standard of 5x10-8 mbar l/s. An added functionality of the proposed method is the possibility to create electrical circuitry on the bond interface, using the laser to modify the metal interlayer, rendering it electrically non-conductive. Biocompatible packages are also possible, by choosing the appropriate interlayer material. This would allow for the fabrication of implantable packages.","PeriodicalId":395835,"journal":{"name":"Photonics West - Micro and Nano Fabricated Electromechanical and Optical Components","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117047645","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
X. Tao, A. Norton, Matthew Kissel, O. Azucena, J. Kubby
A fast direct wavefront sensing method for dynamic in-vivo adaptive optical two photon microscopy has demonstrated. By using the direct wavefront sensing and open loop control, the system provides high-speed wavefront measurement and correction. To measure the wavefront in the middle of a Drosophila embryo at early stages, autofluorescence from endogenous fluorophores in the yolk were used as reference guide-stars. This method does not rely on fluorescently labeled proteins as guide-stars, which can simplify the sample preparation for wavefront measurement. The method was tested through live imaging of a Drosophila embryo. The aberration in the middle of the embryo was measured directly for the first time. After correction, both contrast and signal intensity of the structure in the middle of the embryo was improved.
{"title":"Adaptive optics two photon microscopy with direct wavefront sensing using autofluorescent guide-stars","authors":"X. Tao, A. Norton, Matthew Kissel, O. Azucena, J. Kubby","doi":"10.1117/12.2044090","DOIUrl":"https://doi.org/10.1117/12.2044090","url":null,"abstract":"A fast direct wavefront sensing method for dynamic in-vivo adaptive optical two photon microscopy has demonstrated. By using the direct wavefront sensing and open loop control, the system provides high-speed wavefront measurement and correction. To measure the wavefront in the middle of a Drosophila embryo at early stages, autofluorescence from endogenous fluorophores in the yolk were used as reference guide-stars. This method does not rely on fluorescently labeled proteins as guide-stars, which can simplify the sample preparation for wavefront measurement. The method was tested through live imaging of a Drosophila embryo. The aberration in the middle of the embryo was measured directly for the first time. After correction, both contrast and signal intensity of the structure in the middle of the embryo was improved.","PeriodicalId":395835,"journal":{"name":"Photonics West - Micro and Nano Fabricated Electromechanical and Optical Components","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128529214","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Song Hoon, Geeyoung Sung, Kanghee Won, J. An, Youngjun Yun, J. Jung, Jesada Ungnapatanin, Daryl Lim, Hwi Kim, Hong-Seok Lee, U. Chung
We demonstrate a holographic image reconstructed by a FPD-based complex spatial light modulator (SLM) which is composed of a phase-only SLM and a sheet of beam combiner. A complex SLM which modulates both amplitude and phase independently is necessary for a better image quality with reducing conjugate images. The two-phase encoding method is one of the most practical candidates for the complex SLM. The proposed complex SLM is presented in a phase-only LCD panel which can be manufactured in a conventional LCD process and it was used for generating different phases. The PAL (Parallel-Aligned nematic Liquid crystal) mode is used to modulate the phase without the amplitude change. The film-type beam combiner consists of a prism array and a grating made by a conventional fabrication process. The beam combiner plays a vital role to merge two pixels and to adjust effective complex modulation. In this paper, the holographic image by the proposed complex SLM is verified by the experimental and simulation work in a monochromatic reconstruction. This complex SLM can be scaled up and it is a promising candidate SLM for a large-size holographic 3D display.
{"title":"Holographic display with a FPD-based complex spatial light modulator","authors":"Song Hoon, Geeyoung Sung, Kanghee Won, J. An, Youngjun Yun, J. Jung, Jesada Ungnapatanin, Daryl Lim, Hwi Kim, Hong-Seok Lee, U. Chung","doi":"10.1117/12.2037621","DOIUrl":"https://doi.org/10.1117/12.2037621","url":null,"abstract":"We demonstrate a holographic image reconstructed by a FPD-based complex spatial light modulator (SLM) which is composed of a phase-only SLM and a sheet of beam combiner. A complex SLM which modulates both amplitude and phase independently is necessary for a better image quality with reducing conjugate images. The two-phase encoding method is one of the most practical candidates for the complex SLM. The proposed complex SLM is presented in a phase-only LCD panel which can be manufactured in a conventional LCD process and it was used for generating different phases. The PAL (Parallel-Aligned nematic Liquid crystal) mode is used to modulate the phase without the amplitude change. The film-type beam combiner consists of a prism array and a grating made by a conventional fabrication process. The beam combiner plays a vital role to merge two pixels and to adjust effective complex modulation. In this paper, the holographic image by the proposed complex SLM is verified by the experimental and simulation work in a monochromatic reconstruction. This complex SLM can be scaled up and it is a promising candidate SLM for a large-size holographic 3D display.","PeriodicalId":395835,"journal":{"name":"Photonics West - Micro and Nano Fabricated Electromechanical and Optical Components","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130418897","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Grahmann, A. Merten, R. Ostendorf, Michael Fontenot, D. Bleh, H. Schenk, H. Wagner
In situ process information in the chemical, pharmaceutical or food industry as well as emission monitoring, sensitive trace detection and biological sensing applications would increasingly rely on MIR-spectroscopic analysis in the 3 μm - 12 μm wavelength range. However, cost effective, portable, low power consuming and fast spectrometers with a wide tuning range are not available so far. To provide these MIR-spectrometer properties, the combination of quantum cascade lasers with a MOEMS scanning grating as wavelength selective element in the external cavity is addressed to provide a very compact and fast tunable laser source for spectroscopic analysis.
{"title":"Tunable External Cavity Quantum Cascade Lasers (EC-QCL): an application field for MOEMS based scanning gratings","authors":"J. Grahmann, A. Merten, R. Ostendorf, Michael Fontenot, D. Bleh, H. Schenk, H. Wagner","doi":"10.1117/12.2039950","DOIUrl":"https://doi.org/10.1117/12.2039950","url":null,"abstract":"In situ process information in the chemical, pharmaceutical or food industry as well as emission monitoring, sensitive trace detection and biological sensing applications would increasingly rely on MIR-spectroscopic analysis in the 3 μm - 12 μm wavelength range. However, cost effective, portable, low power consuming and fast spectrometers with a wide tuning range are not available so far. To provide these MIR-spectrometer properties, the combination of quantum cascade lasers with a MOEMS scanning grating as wavelength selective element in the external cavity is addressed to provide a very compact and fast tunable laser source for spectroscopic analysis.","PeriodicalId":395835,"journal":{"name":"Photonics West - Micro and Nano Fabricated Electromechanical and Optical Components","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131236464","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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