The nature of light, extending from the optical to the x-ray regime, is reviewed from a diffraction point of view by comparing field-based statistical optics and photon-based quantum optics approaches. The topic is introduced by comparing historical diffraction concepts based on wave interference, Dirac’s notion of photon self-interference, Feynman’s interference of space–time photon probability amplitudes, and Glauber’s formulation of coherence functions based on photon detection. The concepts are elucidated by a review of how the semiclassical combination of the disparate photon and wave concepts have been used to describe light creation, diffraction, and detection. The origin of the fundamental diffraction limit is then discussed in both wave and photon pictures. By use of Feynman’s concept of probability amplitudes associated with independent photons, we show that quantum electrodynamics, the complete theory of light, reduces in lowest order to the conventional wave formalism of diffraction. As an introduction to multi-photon effects, we then review fundamental one- and two-photon experiments and detection schemes, in particular the seminal Hanbury Brown–Twiss experiment. The formal discourse of the paper starts with a treatment of first-order coherence theory. In first order, the statistical optics and quantum optics formulations of coherence are shown to be equivalent. This is elucidated by a discussion of Zernike’s powerful theorem of partial coherence propagation, a cornerstone of statistical optics, followed by its quantum derivation based on the interference of single-photon probability amplitudes. The treatment is then extended to second-order coherence theory, where the equivalence of wave and particle descriptions is shown to break down. This is illustrated by considering two photons whose space–time probability amplitudes are correlated through nonlinear birth processes, resulting in entanglement or cloning. In both cases, the two-photon diffraction patterns are shown to exhibit resolution below the conventional diffraction limit, defined by the one-photon diffraction patterns. The origin of the reduction is shown to arise from the interference of two-photon probability amplitudes. By comparing first- and second-order diffraction, it is shown that the conventional first-order concept of partial coherence with its limits of chaoticity and first-order coherence has the second-order analogue of partial entanglement, with its limits corresponding to two entangled photons (“entangled biphotons”) and two cloned photons (“cloned biphotons”), the latter being second-order coherent. The concept of cloned biphotons is extended to the case of n cloned photons, resulting in a 1/n reduction of the diffraction limit. In the limit of nth-order coherence, all photons within the nth-order collective state are shown to propagate on particle like trajectories, reproducing the 0th-order ray-optics picture. These results are discussed in terms of the li
{"title":"Overcoming the diffraction limit by multi-photon interference: a tutorial","authors":"J. Stöhr","doi":"10.1364/AOP.11.000215","DOIUrl":"https://doi.org/10.1364/AOP.11.000215","url":null,"abstract":"The nature of light, extending from the optical to the x-ray regime, is reviewed from a diffraction point of view by comparing field-based statistical optics and photon-based quantum optics approaches. The topic is introduced by comparing historical diffraction concepts based on wave interference, Dirac’s notion of photon self-interference, Feynman’s interference of space–time photon probability amplitudes, and Glauber’s formulation of coherence functions based on photon detection. The concepts are elucidated by a review of how the semiclassical combination of the disparate photon and wave concepts have been used to describe light creation, diffraction, and detection. The origin of the fundamental diffraction limit is then discussed in both wave and photon pictures. By use of Feynman’s concept of probability amplitudes associated with independent photons, we show that quantum electrodynamics, the complete theory of light, reduces in lowest order to the conventional wave formalism of diffraction. As an introduction to multi-photon effects, we then review fundamental one- and two-photon experiments and detection schemes, in particular the seminal Hanbury Brown–Twiss experiment. The formal discourse of the paper starts with a treatment of first-order coherence theory. In first order, the statistical optics and quantum optics formulations of coherence are shown to be equivalent. This is elucidated by a discussion of Zernike’s powerful theorem of partial coherence propagation, a cornerstone of statistical optics, followed by its quantum derivation based on the interference of single-photon probability amplitudes. The treatment is then extended to second-order coherence theory, where the equivalence of wave and particle descriptions is shown to break down. This is illustrated by considering two photons whose space–time probability amplitudes are correlated through nonlinear birth processes, resulting in entanglement or cloning. In both cases, the two-photon diffraction patterns are shown to exhibit resolution below the conventional diffraction limit, defined by the one-photon diffraction patterns. The origin of the reduction is shown to arise from the interference of two-photon probability amplitudes. By comparing first- and second-order diffraction, it is shown that the conventional first-order concept of partial coherence with its limits of chaoticity and first-order coherence has the second-order analogue of partial entanglement, with its limits corresponding to two entangled photons (“entangled biphotons”) and two cloned photons (“cloned biphotons”), the latter being second-order coherent. The concept of cloned biphotons is extended to the case of n cloned photons, resulting in a 1/n reduction of the diffraction limit. In the limit of nth-order coherence, all photons within the nth-order collective state are shown to propagate on particle like trajectories, reproducing the 0th-order ray-optics picture. These results are discussed in terms of the li","PeriodicalId":48960,"journal":{"name":"Advances in Optics and Photonics","volume":null,"pages":null},"PeriodicalIF":27.1,"publicationDate":"2019-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41745974","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
V. Micó, Juanjuan Zheng, Javier García, Z. Zalevsky, P. Gao
Quantitative phase microscopy (QPM), a technique combining phase imaging and microscopy, enables visualization of the 3D topography in reflective samples, as well as the inner structure or refractive index distribution of transparent and translucent samples. Similar to other imaging modalities, QPM is constrained by the conflict between numerical aperture (NA) and field of view (FOV): an imaging system with a low NA has to be employed to maintain a large FOV. This fact severely limits the resolution in QPM up to 0.82λ/NA, λ being the illumination wavelength. Consequently, finer structures of samples cannot be resolved by using modest NA objectives in QPM. Aimed to that, many approaches, such as oblique illumination, structured illumination, and speckle illumination (just to cite a few), have been proposed to improve the spatial resolution (or the space–bandwidth product) in phase microscopy by restricting other degrees of freedom (mostly time). This paper aims to provide an up-to-date review on the resolution enhancement approaches in QPM, discussing the pros and cons of each technique as well as the confusion on resolution definition claims on QPM and other coherent microscopy methods. Through this survey, we will review the most appealing and useful techniques for superresolution in coherent microscopy, working with and without lenses and with special attention to QPM. Note that, throughout this review, with the term “superresolution” we denote enhancing the resolution to surpass the limit imposed by diffraction and proportional to λ/NA, rather than the physics limit λ/(2n med ), with n med being the refractive index value of the immersion medium.
{"title":"Resolution enhancement in quantitative phase microscopy","authors":"V. Micó, Juanjuan Zheng, Javier García, Z. Zalevsky, P. Gao","doi":"10.1364/AOP.11.000135","DOIUrl":"https://doi.org/10.1364/AOP.11.000135","url":null,"abstract":"Quantitative phase microscopy (QPM), a technique combining phase imaging and microscopy, enables visualization of the 3D topography in reflective samples, as well as the inner structure or refractive index distribution of transparent and translucent samples. Similar to other imaging modalities, QPM is constrained by the conflict between numerical aperture (NA) and field of view (FOV): an imaging system with a low NA has to be employed to maintain a large FOV. This fact severely limits the resolution in QPM up to 0.82λ/NA, λ being the illumination wavelength. Consequently, finer structures of samples cannot be resolved by using modest NA objectives in QPM. Aimed to that, many approaches, such as oblique illumination, structured illumination, and speckle illumination (just to cite a few), have been proposed to improve the spatial resolution (or the space–bandwidth product) in phase microscopy by restricting other degrees of freedom (mostly time). This paper aims to provide an up-to-date review on the resolution enhancement approaches in QPM, discussing the pros and cons of each technique as well as the confusion on resolution definition claims on QPM and other coherent microscopy methods. Through this survey, we will review the most appealing and useful techniques for superresolution in coherent microscopy, working with and without lenses and with special attention to QPM. Note that, throughout this review, with the term “superresolution” we denote enhancing the resolution to surpass the limit imposed by diffraction and proportional to λ/NA, rather than the physics limit λ/(2n\u0000 med\u0000 ), with n\u0000 med\u0000 being the refractive index value of the immersion medium.","PeriodicalId":48960,"journal":{"name":"Advances in Optics and Photonics","volume":null,"pages":null},"PeriodicalIF":27.1,"publicationDate":"2019-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47907239","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Quantum plasmonics: new opportunity in fundamental and applied photonics: publisher’s note","authors":"Da Xu, X. Xiong, Lin Wu, Xifeng Ren, C. Png, G. Guo, Q. Gong, Yun-Feng Xiao","doi":"10.1364/AOP.10.000939","DOIUrl":"https://doi.org/10.1364/AOP.10.000939","url":null,"abstract":"This publisher’s note corrects errors in the funding and references of Adv. Opt. Photon.10, 703 (2018)AOPAC71943-820610.1364/AOP.10.000703.","PeriodicalId":48960,"journal":{"name":"Advances in Optics and Photonics","volume":null,"pages":null},"PeriodicalIF":27.1,"publicationDate":"2018-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48199197","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Terahertz (THz) science and technology have greatly progressed over the past two decades to a point where the THz region of the electromagnetic spectrum is now a mature research area with many fundamental and practical applications. Furthermore, THz imaging is positioned to play a key role in many industrial applications, as THz technology is steadily shifting from university-grade instrumentation to commercial systems. In this context, the objective of this review is to discuss recent advances in THz imaging with an emphasis on the modalities that could enable real-time high-resolution imaging. To this end, we first discuss several key imaging modalities developed over the years: THz transmission, reflection, and conductivity imaging; THz pulsed imaging; THz computed tomography; and THz near-field imaging. Then, we discuss several enabling technologies for real-time THz imaging within the time-domain spectroscopy paradigm: fast optical delay lines, photoconductive antenna arrays, and electro-optic sampling with cameras. Next, we discuss the advances in THz cameras, particularly THz thermal cameras and THz field-effect transistor cameras. Finally, we overview the most recent techniques that enable fast THz imaging with single-pixel detectors: mechanical beam-steering, compressive sensing, spectral encoding, and fast Fourier optics. We believe that this critical and comprehensive review of enabling hardware, instrumentation, algorithms, and potential applications in real-time high-resolution THz imaging can serve a diverse community of fundamental and applied scientists.
{"title":"Toward real-time terahertz imaging","authors":"H. Guerboukha, K. Nallappan, M. Skorobogatiy","doi":"10.1364/AOP.10.000843","DOIUrl":"https://doi.org/10.1364/AOP.10.000843","url":null,"abstract":"Terahertz (THz) science and technology have greatly progressed over the past two decades to a point where the THz region of the electromagnetic spectrum is now a mature research area with many fundamental and practical applications. Furthermore, THz imaging is positioned to play a key role in many industrial applications, as THz technology is steadily shifting from university-grade instrumentation to commercial systems. In this context, the objective of this review is to discuss recent advances in THz imaging with an emphasis on the modalities that could enable real-time high-resolution imaging. To this end, we first discuss several key imaging modalities developed over the years: THz transmission, reflection, and conductivity imaging; THz pulsed imaging; THz computed tomography; and THz near-field imaging. Then, we discuss several enabling technologies for real-time THz imaging within the time-domain spectroscopy paradigm: fast optical delay lines, photoconductive antenna arrays, and electro-optic sampling with cameras. Next, we discuss the advances in THz cameras, particularly THz thermal cameras and THz field-effect transistor cameras. Finally, we overview the most recent techniques that enable fast THz imaging with single-pixel detectors: mechanical beam-steering, compressive sensing, spectral encoding, and fast Fourier optics. We believe that this critical and comprehensive review of enabling hardware, instrumentation, algorithms, and potential applications in real-time high-resolution THz imaging can serve a diverse community of fundamental and applied scientists.","PeriodicalId":48960,"journal":{"name":"Advances in Optics and Photonics","volume":null,"pages":null},"PeriodicalIF":27.1,"publicationDate":"2018-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42465056","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper presents a review of the subwavelength interference effects of light in structured surfaces. Starting from the anomalous interference in simple structures such as double nanoslits, thin films, and catenary apertures, the theories and applications of light–matter interaction in layered, periodic, and aperiodic subwavelength structures are discussed. Two basic platforms, i.e., Young’s double slits and the Fabry–Perot cavity, are used as prototypes for the investigation of the complex interference of surface waves. It is shown that these novel phenomena could dramatically reduce the characteristic lengths of functional devices and increase the resolution of optical imaging. By engineering the dispersion of surface waves, broadband responses beyond traditional limits in both temporal and spatial regimes have been demonstrated. As a final remark, the current challenges and future trends of subwavelength interference engineering are addressed.
{"title":"Subwavelength interference of light on structured surfaces","authors":"Xian-shu Luo, Dinping Tsai, M. Gu, M. Hong","doi":"10.1364/AOP.10.000757","DOIUrl":"https://doi.org/10.1364/AOP.10.000757","url":null,"abstract":"This paper presents a review of the subwavelength interference effects of light in structured surfaces. Starting from the anomalous interference in simple structures such as double nanoslits, thin films, and catenary apertures, the theories and applications of light–matter interaction in layered, periodic, and aperiodic subwavelength structures are discussed. Two basic platforms, i.e., Young’s double slits and the Fabry–Perot cavity, are used as prototypes for the investigation of the complex interference of surface waves. It is shown that these novel phenomena could dramatically reduce the characteristic lengths of functional devices and increase the resolution of optical imaging. By engineering the dispersion of surface waves, broadband responses beyond traditional limits in both temporal and spatial regimes have been demonstrated. As a final remark, the current challenges and future trends of subwavelength interference engineering are addressed.","PeriodicalId":48960,"journal":{"name":"Advances in Optics and Photonics","volume":null,"pages":null},"PeriodicalIF":27.1,"publicationDate":"2018-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49484938","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Da Xu, X. Xiong, Lin Wu, Xifeng Ren, C. Png, G. Guo, Q. Gong, Yun-Feng Xiao
Surface plasmons allow electromagnetic fields to be confined to subwavelength scale, well beyond the classical optical diffraction limit. With continuous reduction of optical mode volume into the deep subwavelength scale, a new era of quantum plasmonics opens up that investigates the quantum behavior of surface plasmons and their interactions with matter. This emerging and exciting field creates many new opportunities in advancing the boundaries of fundamental science and applied quantum technology. This review covers recent breakthroughs from three unique and important perspectives: the fundamental quantum properties of plasmon-polaritons, plasmon-polaritons interacting with quantum emitters, and plasmon-polaritons stepping into quantum technology. A clear development map of quantum plasmonics is also established for the reader.
{"title":"Quantum plasmonics: new opportunity in fundamental and applied photonics","authors":"Da Xu, X. Xiong, Lin Wu, Xifeng Ren, C. Png, G. Guo, Q. Gong, Yun-Feng Xiao","doi":"10.1364/AOP.10.000703","DOIUrl":"https://doi.org/10.1364/AOP.10.000703","url":null,"abstract":"Surface plasmons allow electromagnetic fields to be confined to subwavelength scale, well beyond the classical optical diffraction limit. With continuous reduction of optical mode volume into the deep subwavelength scale, a new era of quantum plasmonics opens up that investigates the quantum behavior of surface plasmons and their interactions with matter. This emerging and exciting field creates many new opportunities in advancing the boundaries of fundamental science and applied quantum technology. This review covers recent breakthroughs from three unique and important perspectives: the fundamental quantum properties of plasmon-polaritons, plasmon-polaritons interacting with quantum emitters, and plasmon-polaritons stepping into quantum technology. A clear development map of quantum plasmonics is also established for the reader.","PeriodicalId":48960,"journal":{"name":"Advances in Optics and Photonics","volume":null,"pages":null},"PeriodicalIF":27.1,"publicationDate":"2018-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42580640","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
There has been great interest in researching and implementing effective technologies for the capture, processing, and display of 3D images. This broad interest is evidenced by widespread international research and activities on 3D technologies. There is a large number of journal and conference papers on 3D systems, as well as research and development efforts in government, industry, and academia on this topic for broad applications including entertainment, manufacturing, security and defense, and biomedical applications. Among these technologies, integral imaging is a promising approach for its ability to work with polychromatic scenes and under incoherent or ambient light for scenarios from macroscales to microscales. Integral imaging systems and their variations, also known as plenoptics or light-field systems, are applicable in many fields, and they have been reported in many applications, such as entertainment (TV, video, movies), industrial inspection, security and defense, and biomedical imaging and displays. This tutorial is addressed to the students and researchers in different disciplines who are interested to learn about integral imaging and light-field systems and who may or may not have a strong background in optics. Our aim is to provide the readers with a tutorial that teaches fundamental principles as well as more advanced concepts to understand, analyze, and implement integral imaging and light-field-type capture and display systems. The tutorial is organized to begin with reviewing the fundamentals of imaging, and then it progresses to more advanced topics in 3D imaging and displays. More specifically, this tutorial begins by covering the fundamentals of geometrical optics and wave optics tools for understanding and analyzing optical imaging systems. Then, we proceed to use these tools to describe integral imaging, light-field, or plenoptics systems, the methods for implementing the 3D capture procedures and monitors, their properties, resolution, field of view, performance, and metrics to assess them. We have illustrated with simple laboratory setups and experiments the principles of integral imaging capture and display systems. Also, we have discussed 3D biomedical applications, such as integral microscopy.
{"title":"Fundamentals of 3D imaging and displays: a tutorial on integral imaging, light-field, and plenoptic systems","authors":"M. Martínez-Corral, B. Javidi","doi":"10.1364/AOP.10.000512","DOIUrl":"https://doi.org/10.1364/AOP.10.000512","url":null,"abstract":"There has been great interest in researching and implementing effective technologies for the capture, processing, and display of 3D images. This broad interest is evidenced by widespread international research and activities on 3D technologies. There is a large number of journal and conference papers on 3D systems, as well as research and development efforts in government, industry, and academia on this topic for broad applications including entertainment, manufacturing, security and defense, and biomedical applications. Among these technologies, integral imaging is a promising approach for its ability to work with polychromatic scenes and under incoherent or ambient light for scenarios from macroscales to microscales. Integral imaging systems and their variations, also known as plenoptics or light-field systems, are applicable in many fields, and they have been reported in many applications, such as entertainment (TV, video, movies), industrial inspection, security and defense, and biomedical imaging and displays. This tutorial is addressed to the students and researchers in different disciplines who are interested to learn about integral imaging and light-field systems and who may or may not have a strong background in optics. Our aim is to provide the readers with a tutorial that teaches fundamental principles as well as more advanced concepts to understand, analyze, and implement integral imaging and light-field-type capture and display systems. The tutorial is organized to begin with reviewing the fundamentals of imaging, and then it progresses to more advanced topics in 3D imaging and displays. More specifically, this tutorial begins by covering the fundamentals of geometrical optics and wave optics tools for understanding and analyzing optical imaging systems. Then, we proceed to use these tools to describe integral imaging, light-field, or plenoptics systems, the methods for implementing the 3D capture procedures and monitors, their properties, resolution, field of view, performance, and metrics to assess them. We have illustrated with simple laboratory setups and experiments the principles of integral imaging capture and display systems. Also, we have discussed 3D biomedical applications, such as integral microscopy.","PeriodicalId":48960,"journal":{"name":"Advances in Optics and Photonics","volume":null,"pages":null},"PeriodicalIF":27.1,"publicationDate":"2018-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1364/AOP.10.000512","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42528444","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
I. Trumper, P. Hallibert, Jonathan, W., Arenberg, H. Kunieda, O. Guyon, H., Philip Stahl, Dae Wook Kim
This review paper addresses topics of fabrication, testing, alignment, and as-built performance of reflective space optics for the next generation of telescopes across the x-ray to far-infrared spectrum. The technology presented in the manuscript represents the most promising methods to enable a next level of astronomical observation capabilities for space-based telescopes as motivated by the science community. While the technology to produce the proposed telescopes does not exist in its final form, the optics industry is making steady and impressive progress toward these goals across all disciplines. We hope that through sharing these developments in context of the science objectives, further connections and improvements are enabled to push the envelope of the technology.
{"title":"Optics technology for large-aperture space telescopes: from fabrication to final acceptance tests","authors":"I. Trumper, P. Hallibert, Jonathan, W., Arenberg, H. Kunieda, O. Guyon, H., Philip Stahl, Dae Wook Kim","doi":"10.1364/AOP.10.000644","DOIUrl":"https://doi.org/10.1364/AOP.10.000644","url":null,"abstract":"This review paper addresses topics of fabrication, testing, alignment, and as-built performance of reflective space optics for the next generation of telescopes across the x-ray to far-infrared spectrum. The technology presented in the manuscript represents the most promising methods to enable a next level of astronomical observation capabilities for space-based telescopes as motivated by the science community. While the technology to produce the proposed telescopes does not exist in its final form, the optics industry is making steady and impressive progress toward these goals across all disciplines. We hope that through sharing these developments in context of the science objectives, further connections and improvements are enabled to push the envelope of the technology.","PeriodicalId":48960,"journal":{"name":"Advances in Optics and Photonics","volume":null,"pages":null},"PeriodicalIF":27.1,"publicationDate":"2018-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1364/AOP.10.000644","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45422015","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We review recent developments in directly modulated lasers (DMLs) with low operating energy for datacom and computercom applications. Key issues are their operating energy and the cost for employing them in these applications. To decrease the operating energy, it is important to reduce the active volume of the laser while maintaining the cavity Q-factor or photon lifetime in the cavity. Therefore, how to achieve high-reflectivity mirrors has been the main challenge in reducing the operating energy. In terms of the required output power from the lasers, the required input power into the photodetector and the transmission distance determine the lower limit of laser active volume. Therefore, the operating energy and output power are in a trade-off relationship. In designing the lasers, the cavity volume, quantum well number, and optical confinement factor are critical parameters. For reducing the cost, it is important to fabricate a large-scale photonic integrated circuit (PIC) comprising DMLs, an optical multiplexer, and monitor photodetectors because the lower assembly cost reduces the overall cost. In this context, silicon (Si) photonics technology plays a key role in fabricating large-scale PICs with low cost, and heterogeneous integration of DMLs and Si photonics devices has attracted much attention. We will describe fabrication technologies for heterogeneous integration and experimental results for DMLs on a Si substrate.
{"title":"Low-operating-energy directly modulated lasers for short-distance optical interconnects","authors":"S. Matsuo, T. Kakitsuka","doi":"10.1364/AOP.10.000567","DOIUrl":"https://doi.org/10.1364/AOP.10.000567","url":null,"abstract":"We review recent developments in directly modulated lasers (DMLs) with low operating energy for datacom and computercom applications. Key issues are their operating energy and the cost for employing them in these applications. To decrease the operating energy, it is important to reduce the active volume of the laser while maintaining the cavity Q-factor or photon lifetime in the cavity. Therefore, how to achieve high-reflectivity mirrors has been the main challenge in reducing the operating energy. In terms of the required output power from the lasers, the required input power into the photodetector and the transmission distance determine the lower limit of laser active volume. Therefore, the operating energy and output power are in a trade-off relationship. In designing the lasers, the cavity volume, quantum well number, and optical confinement factor are critical parameters. For reducing the cost, it is important to fabricate a large-scale photonic integrated circuit (PIC) comprising DMLs, an optical multiplexer, and monitor photodetectors because the lower assembly cost reduces the overall cost. In this context, silicon (Si) photonics technology plays a key role in fabricating large-scale PICs with low cost, and heterogeneous integration of DMLs and Si photonics devices has attracted much attention. We will describe fabrication technologies for heterogeneous integration and experimental results for DMLs on a Si substrate.","PeriodicalId":48960,"journal":{"name":"Advances in Optics and Photonics","volume":null,"pages":null},"PeriodicalIF":27.1,"publicationDate":"2018-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1364/AOP.10.000567","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41743068","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nonimaging optics is the theory of thermodynamically efficient optics and as such, depends more on thermodynamics than on optics. Historically, nonimaging optics that work as ideal concentrators have been discovered through such heuristic ideas as “edge ray involutes,” “string method,” “simultaneous multiple surface,” and “tailored edge ray concentrator,” without a consistent theoretical definition of what “ideal” means. In this tutorial, we provide a thermodynamic perspective of nonimaging optical designs to shine light on the commonality of all these designing ideas, or what “ideal” nonimaging design means. Hence, in this paper, a condition for the “best” design is proposed based purely on thermodynamic arguments, which we believe have profound consequences. Thermodynamics may also be the most intuitive way for a reader who is new to this subject to understand or study it within a certain framework, instead of learning from sporadic designing methodologies. This way of looking at the problem of efficient concentration and illumination depends on probabilities, the ingredients of entropy, and information theory, while “optics” in the conventional sense recedes into the background. We attempt to link the key concept of nonimaging optics, etendue, with the radiative heat transfer concept of view factor, which may be more familiar to some readers. However, we do not want to limit the readers to a single thermodynamic understanding of this subject. Therefore, two alternative perspectives of nonimaging optics will also be introduced and used throughout the tutorial: the definition of a nonimaging optics design according to the Hilbert integral, and the phase space analysis of the ideal design. The tutorial will be organized as follows: Section 1 highlights the difference between nonimaging and imaging optics, Section 2 describes the thermodynamic understanding of nonimaging optics, Section 3 presents the alternative phase space representation of nonimaging optics, Section 4 describes the most basic nonimaging designs using Hottel’s strings, Section 5 discusses the geometric flow line designing method, and Section 6 summarizes the various concepts of nonimaging optics.
{"title":"Nonimaging optics: a tutorial","authors":"R. Winston, Lun Jiang, Melissa N. Ricketts","doi":"10.1364/AOP.10.000484","DOIUrl":"https://doi.org/10.1364/AOP.10.000484","url":null,"abstract":"Nonimaging optics is the theory of thermodynamically efficient optics and as such, depends more on thermodynamics than on optics. Historically, nonimaging optics that work as ideal concentrators have been discovered through such heuristic ideas as “edge ray involutes,” “string method,” “simultaneous multiple surface,” and “tailored edge ray concentrator,” without a consistent theoretical definition of what “ideal” means. In this tutorial, we provide a thermodynamic perspective of nonimaging optical designs to shine light on the commonality of all these designing ideas, or what “ideal” nonimaging design means. Hence, in this paper, a condition for the “best” design is proposed based purely on thermodynamic arguments, which we believe have profound consequences. Thermodynamics may also be the most intuitive way for a reader who is new to this subject to understand or study it within a certain framework, instead of learning from sporadic designing methodologies. This way of looking at the problem of efficient concentration and illumination depends on probabilities, the ingredients of entropy, and information theory, while “optics” in the conventional sense recedes into the background. We attempt to link the key concept of nonimaging optics, etendue, with the radiative heat transfer concept of view factor, which may be more familiar to some readers. However, we do not want to limit the readers to a single thermodynamic understanding of this subject. Therefore, two alternative perspectives of nonimaging optics will also be introduced and used throughout the tutorial: the definition of a nonimaging optics design according to the Hilbert integral, and the phase space analysis of the ideal design. The tutorial will be organized as follows: Section 1 highlights the difference between nonimaging and imaging optics, Section 2 describes the thermodynamic understanding of nonimaging optics, Section 3 presents the alternative phase space representation of nonimaging optics, Section 4 describes the most basic nonimaging designs using Hottel’s strings, Section 5 discusses the geometric flow line designing method, and Section 6 summarizes the various concepts of nonimaging optics.","PeriodicalId":48960,"journal":{"name":"Advances in Optics and Photonics","volume":null,"pages":null},"PeriodicalIF":27.1,"publicationDate":"2018-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1364/AOP.10.000484","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44100261","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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