We investigate slow light effect of subwavelength gratings via Rayleigh Anomaly on both infinite and finite size high index contrast gratings. Our results show that the local group velocity of the transmitted light can be significantly reduced due to the optical vortex, which can inspire a new mechanism to enhance light-matter interactions for optical sensing and photo detection. However, the slow light effect will diminish as the transmitted light propagates further away from the grating surface, and the slow-down factor decreases as the grating size shrinks.
{"title":"Slow-light effect via Rayleigh anomaly in high contrast gratings","authors":"Kyoung-Youm Kim, Xinyuan Chong, Alan X. Wang","doi":"10.1117/12.2214041","DOIUrl":"https://doi.org/10.1117/12.2214041","url":null,"abstract":"We investigate slow light effect of subwavelength gratings via Rayleigh Anomaly on both infinite and finite size high index contrast gratings. Our results show that the local group velocity of the transmitted light can be significantly reduced due to the optical vortex, which can inspire a new mechanism to enhance light-matter interactions for optical sensing and photo detection. However, the slow light effect will diminish as the transmitted light propagates further away from the grating surface, and the slow-down factor decreases as the grating size shrinks.","PeriodicalId":122702,"journal":{"name":"SPIE OPTO","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124902547","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}
This paper reports on the progress related to a multichannel photonic alignment concept, which aims to achieve submicrometer alignment of the waveguides of two photonic integrated circuits (PICs). The concept consists of two steps: chip-to-chip positioning and fixing provide a coarse alignment after which waveguide-to-waveguide positioning and fixing result in a fine alignment. For the waveguide-to-waveguide alignment, mechanically flexible waveguides are used. Positioning of the waveguides is performed by integrated MEMS actuators. The flexible waveguides and the actuators are both integrated in one of the PICs. This paper reports on the fabrication and the mechanical characterization of the suspended waveguide structures. The flexible waveguide array is created in a PIC which is based on TriPleX technology, i.e. a silicon nitride (Si3N4) core encapsulated in a silicon dioxide (SiO2) cladding. The realized flexible waveguide structures consist of parallel cantilevered waveguide beams and a crossbar that connects the free ends of the waveguide beams. The fabrication of suspended structures consisting of a thick, i.e. 15 µm, TriPleX layer stack is challenged by the compressive mean stress in the SiO2. We have developed a fabrication method for the reliable release of flexible TriPleX structures, resulting in a 96% yield of cantilever beams. The realized suspended waveguide arrays have a natural out-of-plane deformation, which is studied using white light interferometry. Suspended waveguide beams reveal a downward slope at the base of the beams close to 0:5_. In addition to this slope, the beams have a concave upward profile. The constant curvature over the length of the waveguide beams is measured to range from 0:2 µm to 0:8 µm. The profiles measured over the length of the crossbars do not seem to follow a circular curvature. The variation in deflection within crossbars is measured to be smaller than 0:2 µm.
{"title":"Mechanically flexible waveguide arrays for optical chip-to-chip coupling","authors":"T. Peters, M. Tichem","doi":"10.1117/12.2205227","DOIUrl":"https://doi.org/10.1117/12.2205227","url":null,"abstract":"This paper reports on the progress related to a multichannel photonic alignment concept, which aims to achieve submicrometer alignment of the waveguides of two photonic integrated circuits (PICs). The concept consists of two steps: chip-to-chip positioning and fixing provide a coarse alignment after which waveguide-to-waveguide positioning and fixing result in a fine alignment. For the waveguide-to-waveguide alignment, mechanically flexible waveguides are used. Positioning of the waveguides is performed by integrated MEMS actuators. The flexible waveguides and the actuators are both integrated in one of the PICs. This paper reports on the fabrication and the mechanical characterization of the suspended waveguide structures. The flexible waveguide array is created in a PIC which is based on TriPleX technology, i.e. a silicon nitride (Si3N4) core encapsulated in a silicon dioxide (SiO2) cladding. The realized flexible waveguide structures consist of parallel cantilevered waveguide beams and a crossbar that connects the free ends of the waveguide beams. The fabrication of suspended structures consisting of a thick, i.e. 15 µm, TriPleX layer stack is challenged by the compressive mean stress in the SiO2. We have developed a fabrication method for the reliable release of flexible TriPleX structures, resulting in a 96% yield of cantilever beams. The realized suspended waveguide arrays have a natural out-of-plane deformation, which is studied using white light interferometry. Suspended waveguide beams reveal a downward slope at the base of the beams close to 0:5_. In addition to this slope, the beams have a concave upward profile. The constant curvature over the length of the waveguide beams is measured to range from 0:2 µm to 0:8 µm. The profiles measured over the length of the crossbars do not seem to follow a circular curvature. The variation in deflection within crossbars is measured to be smaller than 0:2 µm.","PeriodicalId":122702,"journal":{"name":"SPIE OPTO","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122548745","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}
H. Price, T. Ozawa, N. Goldman, O. Zilberberg, I. Carusotto
Recent advances in silicon ring-resonator arrays have stimulated the development of topological lattices for photons, with potential applications in integrated photonic devices. Taking inspiration from ultracold atoms, we propose how such arrays can be extended into an additional synthetic dimension by coupling together the different modes of each ring resonator.1 In this way, a 1D resonator chain can become an effective 2D system, while a 3D resonator array can be exploited as a 4D photonic lattice. As an example of the power of this approach, we discuss how to experimentally realise an optical analogue of the 4D quantum Hall effect for the first time. This opens up the way towards the exploration of higher-dimensional lattices in integrated photonics.
{"title":"Towards four-dimensional photonics","authors":"H. Price, T. Ozawa, N. Goldman, O. Zilberberg, I. Carusotto","doi":"10.1117/12.2218539","DOIUrl":"https://doi.org/10.1117/12.2218539","url":null,"abstract":"Recent advances in silicon ring-resonator arrays have stimulated the development of topological lattices for photons, with potential applications in integrated photonic devices. Taking inspiration from ultracold atoms, we propose how such arrays can be extended into an additional synthetic dimension by coupling together the different modes of each ring resonator.1 In this way, a 1D resonator chain can become an effective 2D system, while a 3D resonator array can be exploited as a 4D photonic lattice. As an example of the power of this approach, we discuss how to experimentally realise an optical analogue of the 4D quantum Hall effect for the first time. This opens up the way towards the exploration of higher-dimensional lattices in integrated photonics.","PeriodicalId":122702,"journal":{"name":"SPIE OPTO","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127689972","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}
R. Walker, H. Ding, D. Coulas, D. Grobnic, P. Lu, S. Mihailov, M. Duchesne, R. Hughes, D. McCalden, Ryan Burchat, Robert Yandon
Femtosecond pulse duration infrared laser (fs-IR) written fiber Bragg gratings (FBGs), have demonstrated great potential for extreme environment sensing. Harsh environments are inherent to the advanced power plant technologies under development to reduce greenhouse gas emissions. The performance of new power systems are currently limited by the lack of sensors and controls capable of withstanding the high temperature, pressure and corrosive conditions present. This paper discusses fabrication and deployment of several fs-IR written FBG arrays, for monitoring the temperature distribution within a fluidized bed combustor. Results include: calibration data to ~ 1100 °C, discussion of deployment strategies, contrast with thermocouple data, and comments on reliability.
{"title":"High temperature monitoring of an oxy-fuel fluidized bed combustor using femtosecond infrared laser written fiber Bragg gratings","authors":"R. Walker, H. Ding, D. Coulas, D. Grobnic, P. Lu, S. Mihailov, M. Duchesne, R. Hughes, D. McCalden, Ryan Burchat, Robert Yandon","doi":"10.1117/12.2209399","DOIUrl":"https://doi.org/10.1117/12.2209399","url":null,"abstract":"Femtosecond pulse duration infrared laser (fs-IR) written fiber Bragg gratings (FBGs), have demonstrated great potential for extreme environment sensing. Harsh environments are inherent to the advanced power plant technologies under development to reduce greenhouse gas emissions. The performance of new power systems are currently limited by the lack of sensors and controls capable of withstanding the high temperature, pressure and corrosive conditions present. This paper discusses fabrication and deployment of several fs-IR written FBG arrays, for monitoring the temperature distribution within a fluidized bed combustor. Results include: calibration data to ~ 1100 °C, discussion of deployment strategies, contrast with thermocouple data, and comments on reliability.","PeriodicalId":122702,"journal":{"name":"SPIE OPTO","volume":"95 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134379897","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}
G. Poulopoulos, C. Baskiotis, D. Kalavrouziotis, L. Brusberg, H. Schröder, D. Apostolopoulos, H. Avramopoulos
We demonstrate, for the first time to our knowledge, a SiN-assisted in-plane adiabatic coupler between SiPh and onboard glass waveguides. Our numerical study is founded on an actual graded index glass waveguide developed by Fraunhofer-IZM. The Silicon taper profile and the optimal length are extracted employing the supermode theory and the adiabatic theorem. Fabrication and assembly issues are investigated, resulting to an optimized coupler design that exhibits a theoretical Si-to-glass loss below 0.1dB over the entire C-band. The proposed solution can be realized utilizing standard passive flip-chip assembly equipment and is, therefore, cost-effective, easy to be fabricated, and well-suited for compact packaging.
{"title":"SiN-assisted flip-chip adiabatic coupler between SiPh and Glass OPCBs","authors":"G. Poulopoulos, C. Baskiotis, D. Kalavrouziotis, L. Brusberg, H. Schröder, D. Apostolopoulos, H. Avramopoulos","doi":"10.1117/12.2208878","DOIUrl":"https://doi.org/10.1117/12.2208878","url":null,"abstract":"We demonstrate, for the first time to our knowledge, a SiN-assisted in-plane adiabatic coupler between SiPh and onboard glass waveguides. Our numerical study is founded on an actual graded index glass waveguide developed by Fraunhofer-IZM. The Silicon taper profile and the optimal length are extracted employing the supermode theory and the adiabatic theorem. Fabrication and assembly issues are investigated, resulting to an optimized coupler design that exhibits a theoretical Si-to-glass loss below 0.1dB over the entire C-band. The proposed solution can be realized utilizing standard passive flip-chip assembly equipment and is, therefore, cost-effective, easy to be fabricated, and well-suited for compact packaging.","PeriodicalId":122702,"journal":{"name":"SPIE OPTO","volume":"161 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132034538","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}
S. M. Sherif, L. Shahada, D. Zografopoulos, R. Beccherelli, M. Swillam
We introduce a compact plasmonic resonator that is capable of generating a Fano resonance in the transmission spectrum. The Fano resonance is observed with its unique lineshape. The proposed design is simple, compact, easy to fabricate and can be easily developed for different applications. The device structure is made of a gold layer, a metalinsulator- metal waveguide, and a rectangular cavity. As an application to the proposed plasmonic resonator, we introduce a gas sensor which is operational at the near infrared spectral range. The sensor possesses a high sensitivity of 1500nm/RIU at the telecom wavelength 1.55μm. FDTD simulation tools were conducted for the optimization of the device structure and obtaining the results.
{"title":"Near infrared plasmonic sensor based on Fano resonance","authors":"S. M. Sherif, L. Shahada, D. Zografopoulos, R. Beccherelli, M. Swillam","doi":"10.1117/12.2214216","DOIUrl":"https://doi.org/10.1117/12.2214216","url":null,"abstract":"We introduce a compact plasmonic resonator that is capable of generating a Fano resonance in the transmission spectrum. The Fano resonance is observed with its unique lineshape. The proposed design is simple, compact, easy to fabricate and can be easily developed for different applications. The device structure is made of a gold layer, a metalinsulator- metal waveguide, and a rectangular cavity. As an application to the proposed plasmonic resonator, we introduce a gas sensor which is operational at the near infrared spectral range. The sensor possesses a high sensitivity of 1500nm/RIU at the telecom wavelength 1.55μm. FDTD simulation tools were conducted for the optimization of the device structure and obtaining the results.","PeriodicalId":122702,"journal":{"name":"SPIE OPTO","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131837814","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}
Lingjun Jiang, Stephen R. Anderson, H. Taleb, Z. Huang, Weimin Zhou
In this work, we have designed a novel Si based 1-dimensional high contrast meta-structure waveguide that has slow light effect as well as phase tunability using p-n junction. The goal is to use such waveguide to design active optical devices such as high frequency modulators and tunable filters for analog RF-photonics or data communication applications. The Si ridge waveguide has a pair of high contrast grating wings adhered to the waveguide core in the center. Grating bars at two sides of the waveguide are doped P and N-type respectively, while a p-n junction region is formed in the middle of the waveguide core. By applying a voltage to bias the p-n junction, one can sweep the free carriers to change the effective index of the waveguide as well as the dispersion property of the grating. This metastructure Si waveguide is ideal in the design of high frequency optical modulators since the slow light effect can reduce the modulator waveguide length, increase the modulation efficiency as well as compensate other nonlinearity factors of the modulator for analog applications.
{"title":"Active tunable high contrast meta-structure Si waveguide","authors":"Lingjun Jiang, Stephen R. Anderson, H. Taleb, Z. Huang, Weimin Zhou","doi":"10.1117/12.2216273","DOIUrl":"https://doi.org/10.1117/12.2216273","url":null,"abstract":"In this work, we have designed a novel Si based 1-dimensional high contrast meta-structure waveguide that has slow light effect as well as phase tunability using p-n junction. The goal is to use such waveguide to design active optical devices such as high frequency modulators and tunable filters for analog RF-photonics or data communication applications. The Si ridge waveguide has a pair of high contrast grating wings adhered to the waveguide core in the center. Grating bars at two sides of the waveguide are doped P and N-type respectively, while a p-n junction region is formed in the middle of the waveguide core. By applying a voltage to bias the p-n junction, one can sweep the free carriers to change the effective index of the waveguide as well as the dispersion property of the grating. This metastructure Si waveguide is ideal in the design of high frequency optical modulators since the slow light effect can reduce the modulator waveguide length, increase the modulation efficiency as well as compensate other nonlinearity factors of the modulator for analog applications.","PeriodicalId":122702,"journal":{"name":"SPIE OPTO","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115914799","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}
Z. Wang, Xiaochuan Xu, D. Fan, Yaguo Wang, Ray T. Chen
In recent decades, silicon photonics has attracted intensive research interest in optical communications due to its advantageous compact dimensions and high-volume manufacturability. Particularly, micro-ring resonators on silicon-oninsulator (SOI) platform have been widely exploited as a basic building block for a vast range of applications such as switches, modulators, and sensors. A majority of these applications involve light-matter interaction, which can be substantially enhanced by the high quality factor micro-ring resonators. However, conventional strip waveguide based micro-ring resonators suffer from the intrinsic dilemma in achieving high light confinement and strong light-matter interaction simultaneously. Subwavelength grating (SWG) waveguides, comprised of periodically interleaved high and low refractive index materials with a pitch less than one wavelength, have been demonstrated as a promising alternative. For SWG waveguides built on SOI wafers, the ratio of silicon and cladding materials can be engineered microscopically to achieve desired macroscopic properties. The control of these properties could potentially lead to significant performance improvements compared with conventional micro-ring resonators based photonic devices, such as filters and sensors. However, SWG waveguide based micro-ring resonators (SWGMRs) that have been demonstrated so far can only provide a moderate quality factor (~5600) with a large radius (e.g. 15 μm), which greatly jeopardize the wide spread research efforts in this area. In this paper, we propose to use trapezoidal silicon pillars to reduce the bend loss of SWGMRs to improve the quality factor. For the first time, we experimentally demonstrate the smallest SWGMR (the micro-ring radius equals to 5 μm) with an applicable quality factor as high as 11,500. This approach also can be applied to SWGMRs with larger radii for higher quality factors. We also experimentally demonstrated a 10 μm radius SWGMR that can provide a quality factor up to 45,000. Compared to SWGMRs built with conventional rectangular silicon pillars, the quality factors is increased by 4.6 times from a 5 μm radius SWGMR and 3 times from a 10 μm SWGMR radius, respectively.
{"title":"High quality factor trapezoidal subwavelength grating waveguide micro-ring resonator","authors":"Z. Wang, Xiaochuan Xu, D. Fan, Yaguo Wang, Ray T. Chen","doi":"10.1117/12.2213935","DOIUrl":"https://doi.org/10.1117/12.2213935","url":null,"abstract":"In recent decades, silicon photonics has attracted intensive research interest in optical communications due to its advantageous compact dimensions and high-volume manufacturability. Particularly, micro-ring resonators on silicon-oninsulator (SOI) platform have been widely exploited as a basic building block for a vast range of applications such as switches, modulators, and sensors. A majority of these applications involve light-matter interaction, which can be substantially enhanced by the high quality factor micro-ring resonators. However, conventional strip waveguide based micro-ring resonators suffer from the intrinsic dilemma in achieving high light confinement and strong light-matter interaction simultaneously. Subwavelength grating (SWG) waveguides, comprised of periodically interleaved high and low refractive index materials with a pitch less than one wavelength, have been demonstrated as a promising alternative. For SWG waveguides built on SOI wafers, the ratio of silicon and cladding materials can be engineered microscopically to achieve desired macroscopic properties. The control of these properties could potentially lead to significant performance improvements compared with conventional micro-ring resonators based photonic devices, such as filters and sensors. However, SWG waveguide based micro-ring resonators (SWGMRs) that have been demonstrated so far can only provide a moderate quality factor (~5600) with a large radius (e.g. 15 μm), which greatly jeopardize the wide spread research efforts in this area. In this paper, we propose to use trapezoidal silicon pillars to reduce the bend loss of SWGMRs to improve the quality factor. For the first time, we experimentally demonstrate the smallest SWGMR (the micro-ring radius equals to 5 μm) with an applicable quality factor as high as 11,500. This approach also can be applied to SWGMRs with larger radii for higher quality factors. We also experimentally demonstrated a 10 μm radius SWGMR that can provide a quality factor up to 45,000. Compared to SWGMRs built with conventional rectangular silicon pillars, the quality factors is increased by 4.6 times from a 5 μm radius SWGMR and 3 times from a 10 μm SWGMR radius, respectively.","PeriodicalId":122702,"journal":{"name":"SPIE OPTO","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115390813","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}
D. Panda, S. Shetty, A. Balgarkashi, H. Ghadi, N. Sehara, S. Chakrabarti
In this paper, we have reported the optical and electrical properties of strain coupled multi-stack quantum dot infrared photodetectors (QDIPs) of In0.5Ga0.5As dots with different capping compositions. Bilayer, trilayer, pentalayer and heptalayer coupled QDIPs are grown by solid source molecular beam epitaxy with one set of samples containing conventional GaAs capping (12nm) and second set containing a combinational capping of In0.15Ga0.85As (3nm) and GaAs (9nm) layers with same total thickness. The entire set of strain coupled quantum dots (QDs) shows a red shift in ground state photoluminescence peak in comparison to the uncoupled structures. Due to the reduction in indium interdiffusion from In0.5Ga0.5As dots in the combinational capped structures, a higher redshift is observed compared to the GaAs capped structures, which attributes larger dot size in the former ones. Full width half maximum value (FWHM) of In0.15Ga0.85As/GaAs capped QDs are lower, showing uniform distribution of dot size compared to the corresponding GaAs capped QDs. Trilayer sample with In0.15Ga0.85As/GaAs capping shows the best result in terms of the peak emission wavelength of 1177nm, FWHM of 15.67nm and activation energy of 339meV compared to all the structures. Trilayer sample seems to be the optimum stacking having the best confinement resulting lower dark current density of 6.5E-8 A/cm2 measured at 100K. The sample also shows a multicolor response at ~4.89μm and at ~7.08μm in the mid infrared range. Further optimization of the spacer thickness and dot layer deposition can improve the response towards the long infrared range.
{"title":"Effect of varying capping composition and number of strain-coupled stacks on In0.5Ga0.5As quantum dot infrared photodetectors","authors":"D. Panda, S. Shetty, A. Balgarkashi, H. Ghadi, N. Sehara, S. Chakrabarti","doi":"10.1117/12.2209308","DOIUrl":"https://doi.org/10.1117/12.2209308","url":null,"abstract":"In this paper, we have reported the optical and electrical properties of strain coupled multi-stack quantum dot infrared photodetectors (QDIPs) of In0.5Ga0.5As dots with different capping compositions. Bilayer, trilayer, pentalayer and heptalayer coupled QDIPs are grown by solid source molecular beam epitaxy with one set of samples containing conventional GaAs capping (12nm) and second set containing a combinational capping of In0.15Ga0.85As (3nm) and GaAs (9nm) layers with same total thickness. The entire set of strain coupled quantum dots (QDs) shows a red shift in ground state photoluminescence peak in comparison to the uncoupled structures. Due to the reduction in indium interdiffusion from In0.5Ga0.5As dots in the combinational capped structures, a higher redshift is observed compared to the GaAs capped structures, which attributes larger dot size in the former ones. Full width half maximum value (FWHM) of In0.15Ga0.85As/GaAs capped QDs are lower, showing uniform distribution of dot size compared to the corresponding GaAs capped QDs. Trilayer sample with In0.15Ga0.85As/GaAs capping shows the best result in terms of the peak emission wavelength of 1177nm, FWHM of 15.67nm and activation energy of 339meV compared to all the structures. Trilayer sample seems to be the optimum stacking having the best confinement resulting lower dark current density of 6.5E-8 A/cm2 measured at 100K. The sample also shows a multicolor response at ~4.89μm and at ~7.08μm in the mid infrared range. Further optimization of the spacer thickness and dot layer deposition can improve the response towards the long infrared range.","PeriodicalId":122702,"journal":{"name":"SPIE OPTO","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114629878","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}
We generated a fully complex hologram by utilizing a combination of amplitude and phase spatial light modulators. A digital micromirror device (DMD) was used to produce the amplitude profile, and a liquid crystal spatial light modulator (SLM) produced the phase profile. A band-limited 4-f imaging system imaged the DMD onto the SLM to create a fully complex modulated wavefront, which reconstructed a holographic image at the desired location. We utilized backwards diffraction calculations, error-diffusion, and amplitude beam-shaping to design a hologram with small reconstruction error.
{"title":"Experimental demonstration of precise holograms using complex light modulation","authors":"V. Parthiban, R. Kohn, Jinyang Liang, M. Becker","doi":"10.1117/12.2208316","DOIUrl":"https://doi.org/10.1117/12.2208316","url":null,"abstract":"We generated a fully complex hologram by utilizing a combination of amplitude and phase spatial light modulators. A digital micromirror device (DMD) was used to produce the amplitude profile, and a liquid crystal spatial light modulator (SLM) produced the phase profile. A band-limited 4-f imaging system imaged the DMD onto the SLM to create a fully complex modulated wavefront, which reconstructed a holographic image at the desired location. We utilized backwards diffraction calculations, error-diffusion, and amplitude beam-shaping to design a hologram with small reconstruction error.","PeriodicalId":122702,"journal":{"name":"SPIE OPTO","volume":"57 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123821925","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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