Roadmap on multimode light shaping

Our ability to generate new distributions of light has been remarkably enhanced in recent years. At the most fundamental level, these light patterns are obtained by ingeniously combining different electromagnetic modes. Interestingly, the modal superposition occurs in the spatial, temporal as well as spatio-temporal domain. This generalized concept of structured light is being applied across the entire spectrum of optics: generating classical and quantum states of light, harnessing linear and nonlinear light-matter interactions, and advancing applications in microscopy, spectroscopy, holography, communication, and synchronization. This Roadmap highlights the common roots of these different techniques and thus establishes links between research areas that complement each other seamlessly. We provide an overview of all these areas, their backgrounds, current research, and future developments. We highlight the power of multimodal light manipulation and want to inspire new eclectic approaches in this vibrant research community.acceptedVersionPeer reviewe

Integrated Ultra-High-Q Nonlinear Photonic Platform for On-Chip Optoelectronic Systems

Silicon technology provided a concrete basis of the integrated microelectronics revolution, and it might usher disruptive advances in photonics again. An integrated photonic system can potentially revolutionize instrumentation, time standards, spectroscopy, and navigation. Driven by these applications, various high-Q platforms have emerged over the last decade. However, applications require to satisfy challenging combinations of ultra-high-Q (UHQ) cavity performance, monolithic integration, and nonlinear cavity designs: the monolithic integration of UHQ devices still remains elusive. In this thesis, an integrated UHQ microcavity is demonstrated for the first time. A silicon nitride waveguide is monolithically integrated with a silicon oxide cavity, and the integrated waveguide can provide nearly universal interface to other photonic devices. Significantly, this thesis discusses far beyond setting a new record for integrated Q factor: the integrated UHQ cavity provides functionality as soliton source with electronic-repetition-rates. Demonstration of low-pump-power soliton generation at 15 GHz was previously possible in only discrete devices but essentially required for integrated self-referenced comb, which can unlock new level of performance and scale in an optoelectronic system. In addition, nonlinear cavity design is another outstanding challenge towards a further development on the optoelectronic system, and will be discussed in this thesis. The dispersion-engineered platform can potentially tailor the spectral bandwidth of frequency comb, and extend the frequency comb to visible and ultraviolet band. Importantly, the design methods are directly transferable to the integrated platform

Roadmap on structured light

Structured light refers to the generation and application of custom light fields. As the tools and technology to create and detect structured light have evolved, steadily the applications have begun to emerge. This roadmap touches on the key fields within structured light from the perspective of experts in those areas, providing insight into the current state and the challenges their respective fields face. Collectively the roadmap outlines the venerable nature of structured light research and the exciting prospects for the future that are yet to be realized

Photodetectors

In this book some recent advances in development of photodetectors and photodetection systems for specific applications are included. In the first section of the book nine different types of photodetectors and their characteristics are presented. Next, some theoretical aspects and simulations are discussed. The last eight chapters are devoted to the development of photodetection systems for imaging, particle size analysis, transfers of time, measurement of vibrations, magnetic field, polarization of light, and particle energy. The book is addressed to students, engineers, and researchers working in the field of photonics and advanced technologies

Coherence in ultrashort light pulses and applications in temporal optics.

In the last decades, the generation of lasers delivering pulses with durations in the order of femtosecond has constituted an important research topic for the Physics and Engineering communities. The characteristics of this kind of radiation, i.e., broadband spectrum, enormous temporal resolution, high peak-power with low energy average, potentially high repetition rate and high spatial coherence make it an indispensable tool in order to develop many applications in different fields of science and technology. Ultrafast laser technology is ready to offer real world applications ranging from high-tech, such us high-speed circuit testing and biological imaging, to more industrial applications like quality control. The markets that are already or will be influenced in the near future include industries as telecommunications, automotive, electronics, medical and inspection of consumer goods, to name only a few. In this direction, the so-called Space-Time analogy is an important tool for designing new schemes for ultrashort light pulse processing. It is based on the formal similitude between the diffraction of 1D light beams and the distortion of short light pulses in a first-order dispersive medium. In this Thesis, we have extended this analogy from the fully coherent to the partially coherent and quantum regimes. In the fully coherent regime in particular, we have proposed a new system for the tuning of spectral envelope of a short light pulse without altering the input profile. In addition, we have explained the phenomenon of phase-to-amplitude conversion in terms of the Fresnel images of a phase-only diffraction grating. In the partially coherent regime, we have made use of the optical coherence theory to analyze theoretically the influence of the finite source linewidth optical communication systems, as well as the distortion of optical frequency combs due to the general noise in mode-locked lasers. Alternatively, we have proposed and experimentally verified a technique for arbitrary radio-frequency and microwave waveform generation that operates with incoherent broadband light. Finally, in the quantum regime, we have recognized an analogy between the distortion of entangled photons and partially coherent pulses in dispersive media. This similarity has allowed us to point out that many quantum systems do not really require a two-photon light source, so that their complexity can be greatly reduced. __________________________________________________________________________________________________ RESUMEN En las últimas décadas, la generación de haces ópticos pulsados con una duración temporal del orden del pico y femtosegundo ha constituido uno de los temas de investigación más candentes en el ámbito de la Física y la Ingeniería. Los sectores que se benefician o beneficiarán de esta tecnología en un futuro cercano incluyen industrias como telecomunicaciones, automoción, electrónica, diagnóstico médico y control de calidad. Todas las potenciales aplicaciones de los pulsos ultracortos requieren de un procesado y manipulación con extremada precisión en el dominio óptico. En esta dirección, la denominada analogía Espacio-Tiempo constituye una importante herramienta para la adaptación de nuevas técnicas ultrarrápidas, basándose en la similitud formal que existe entre la difracción de haces ópticos y la distorsión de pulsos ultracortos en medios dispersivos. En esta Tesis, se ha extendido esta analogía del caso puramente coherente hasta los regímenes parcialmente coherente y cuántico. En el régimen coherente en particular, se ha propuesto un nuevo sistema para la sintonización del ancho de banda de un pulso ultracorto sin cambiar el perfil espectral. Asimismo, se ha explicado el efecto de conversión de onda continua a radiación pulsada en términos de las imágenes de Fresnel de una red pura de fase. En el régimen parcialmente coherente, se ha utilizado la teoría de la coherencia óptica para analizar teóricamente la influencia del ancho de línea en sistemas ópticos de comunicaciones, así como la distorsión de peines de frecuencia debido al ruido presente en todos los sistemas láser. Por otro lado, se ha propuesto y verificado experimentalmente una técnica que utiliza luz incoherente de banda ancha para le generación de perfiles arbitrarios de señales de microondas. Finalmente, en el régimen cuántico, se ha reconocido una similitud formal entre la distorsión de luz cuántica entrelazada tipo dos fotones y los pulsos parcialmente coherentes. Esto ha permitido destacar que muchos sistemas cuánticos actualmente en estudio no necesitan realmente una fuente de dos fotones, por lo que su complejidad puede ser reducida enormemente

Integrated butt-coupled membrane laser for Indium Phosphide on Silicon platform

In this work we present the design and technology development for an integrated butt-coupled membrane laser in the IMOS (Indium Phosphide Membrane On Silicon) platform . Laser is expected to have a small footprint (less than 50 µm 2 ), 1 mA threshold current and a direct modulation frequency of 10 GHz

2023 Astrophotonics Roadmap: pathways to realizing multi-functional integrated astrophotonic instruments

This is the final version. Available on open access from IOP Publishing via the DOI in this recordData availability statement: The data that support the findings of this study are available upon reasonable request from the authors.Photonic technologies offer numerous functionalities that can be used to realize astrophotonic instruments. The most spectacular example to date is the ESO Gravity instrument at the Very Large Telescope in Chile that combines the light-gathering power of four 8 m telescopes through a complex photonic interferometer. Fully integrated astrophotonic devices stand to offer critical advantages for instrument development, including extreme miniaturization when operating at the diffraction-limit, as well as integration, superior thermal and mechanical stabilization owing to the small footprint, and high replicability offering significant cost savings. Numerous astrophotonic technologies have been developed to address shortcomings of conventional instruments to date, including for example the development of photonic lanterns to convert from multimode inputs to single mode outputs, complex aperiodic fiber Bragg gratings to filter OH emission from the atmosphere, complex beam combiners to enable long baseline interferometry with for example, ESO Gravity, and laser frequency combs for high precision spectral calibration of spectrometers. Despite these successes, the facility implementation of photonic solutions in astronomical instrumentation is currently limited because of (1) low throughputs from coupling to fibers, coupling fibers to chips, propagation and bend losses, device losses, etc, (2) difficulties with scaling to large channel count devices needed for large bandwidths and high resolutions, and (3) efficient integration of photonics with detectors, to name a few. In this roadmap, we identify 24 key areas that need further development. We outline the challenges and advances needed across those areas covering design tools, simulation capabilities, fabrication processes, the need for entirely new components, integration and hybridization and the characterization of devices. To realize these advances the astrophotonics community will have to work cooperatively with industrial partners who have more advanced manufacturing capabilities. With the advances described herein, multi-functional integrated instruments will be realized leading to novel observing capabilities for both ground and space based platforms, enabling new scientific studies and discoveries.National Science Foundation (NSF)NAS

Photonic Crystal Optical Frequency Combs

Nanophotonics, driven by low processing power and high-density integration, is emerging as the next logical step for photonic integrated circuits. Microwave photonics is a diverse research topic that is set to transform traditional microwave electronics. In this thesis, the two topics are combined by investigating the ability for nanophotonic devices to harbour and generate microwave photonic signals. Generating an optical frequency comb (OFC) plays a vital role in integrated microwave photonics. By investigating the different OFC generation methods as well as the capabilities offered in photonic crystal (PhC) devices, a method to produce an OFC from nanoscale devices is proposed. The proposal is modelled using calculations based on temporal coupled mode theory. Analysis shows that a broadband OFC can be produced using nanoscale devices that favour high-density integration. The experimental results in this thesis are based around three fundamental areas: PhC device fabrication, optical characterisation and microwave photonic characterisation. Each chapter builds towards the overarching theme of microwave photonic signal processing at telecommunication wavelengths in a nanophotonic device. A new fabrication process for etching PhC structures in nonthermalised InP samples is developed. The developed process has excellent applications in fabrication where the use of thermal grease or a high sample stage temperature is impractical. Optical characterisation of the fabricated samples shows the effects of lithographic and photothermal tuning on the cavity mode frequency. Through this analysis, resonant cavity modes can be designed for a working wavelength within the telecommunication bandwidth. Temporal analysis shows that carrier lifetimes from a QD ensemble that spectrally and spatially overlaps with the PhC cavity are greatly reduced. Finally, a new measurement set-up is proposed and analysed for the characterisation of microwave photonic signals in nanoscale devices. It is shown that the integration of an ultra-fast laser and a two-arm Mach-Zehnder interferometer can generate a microwave signal within the spectrum of the ultra-fast laser. This signal is integrated into the standard optical characterisation set-up, where it is used to excite PhC optical devices. The results show that the microwave signal present in the ultra-fast laser can be resolved in the emission spectrum of QDs weakly coupled to a PhC cavity

The Boston University Photonics Center annual report 2012-2013

This repository item contains an annual report that summarizes activities of the Boston University Photonics Center in the 2012-2013 academic year. The report provides quantitative and descriptive information regarding photonics programs in education, interdisciplinary research, business innovation, and technology development. The Boston University Photonics Center (BUPC) is an interdisciplinary hub for education, research, scholarship, innovation, and technology development associated with practical uses of light.This report summarizes activities of the Boston University Photonics Center during the period July 2012 through June 2013. These activities span the Center’s complementary missions in education, research, technology development, and commercialization. The Photonics Center continues to grow as an international leader in photonics research, while executing the Center’s strategic plan and serving as a university-wide resource for several affiliate Centers. For more information about the strategic plan, read the Photonics Center Strategic Plan section on page 10. In research, Photonics Center faculty published nearly 150 journal papers spanning the field of photonics. A number of awards for outstanding achievement in education and research were presented to Photonics Center faculty members, including a Peter Paul Professorship for Professor Xue Han, an NSF Career Award for Professor Ajay Joshi, and the 2012 Innovator of the Year Award from Boston University for Professor Theodore Moustakas. New external grant funding for the 2012- 2013 fiscal year totaled over $21.8M. For more information on our research activities, read the Research section on page 24. In technology development, the Photonics Center has turned a chapter, by completing the transition from a focus on Defense/ Security applications to a focus on the healthcare market sector. The commercial sector is expected to energize the technology development efforts for the foreseeable future, but the roots in defense/security are still important and the Center will continue to pursue new research grants in this area. For more information on our technology development program and on specific projects, read the Technology Development section on page 45. In education, 20 Photonics Center graduate students received Ph.D. diplomas. Photonics Center faculty taught 32 photonics courses. The Center supported a Research Experiences for Teachers (RET) site in Biophotonic Sensors and Systems for 10 middle school and high school teachers. The Photonics Center sponsored the Herbert J. Berman “Future of Light” Prize at the University’s Scholars Day. For more on our education programs, read the Education section on page 54. In commercialization, Boston University’s Business Innovation Center (BIC) currently hosts seven technology start-up companies. There is a healthy turnover in the Innovation Center space with a total of 19 companies residing at BIC over the past year. The mix of companies includes: life sciences, biotechnology, medical devices, photonics, and clean energy; and nine of the 19 companies originated from within BU. All the BIC tenants are engaged in the commercialization of new technologies of importance to society and all are active in the BU community in terms of offering internships, employment opportunities or research collaborations. For more information about Business Innovation Center activities, read the Business Innovation Center chapter in the Facilities and Equipment section on page 66