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AO DIVER: Development of a three-dimensional adaptive optics system to advance the depth limits of multiphoton imaging APL Photonics (IF 4.864) Pub Date : 2020-12-24 S. Leemans; A. Dvornikov; T. Gallagher; E. Gratton
Multiphoton microscopy (MPM) can non-invasively measure the dynamic biochemical properties deep in scattering biological samples and has the potential to accelerate clinical research with advances in deep tissue imaging. However, in most samples, the imaging depth of MPM is limited to fractions of a millimeter due to blurring caused by refractive index mismatching throughout tissue and background fluorescence
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Generation of 280 THz-spanning near-ultraviolet light in lithium niobate-on-insulator waveguides with sub-100 pJ pulses APL Photonics (IF 4.864) Pub Date : 2020-12-07 Marc Reig Escalé; Fabian Kaufmann; Hehai Jiang; David Pohl; Rachel Grange
Integrated optics has weak ultraviolet and near-ultraviolet (NUV) light conversion due to its strong material dispersion and large propagation losses. To reach this spectral range, we use non-centrosymmetric waveguides that convert near-infrared (NIR) supercontinuum light into broadband NUV light. We measure a 280 THz span that reaches the upper frequency of 851 THz (352 nm) in a 14-mm long rib waveguide
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Turbulence-free interference induced by the turbulence itself APL Photonics (IF 4.864) Pub Date : 2020-12-11 Thomas A. Smith; Yanhua Shih
When a laser beam is incident on a double-slit interferometer without turbulence, the classic Young’s double-slit interference is present in the first-order measurement of the mean photon number (or intensity), while the second-order measurement of photon number fluctuation correlation (or intensity fluctuation correlation) yields a trivial constant. When optical turbulence is introduced, it destroys
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Simple single-section diode frequency combs APL Photonics (IF 4.864) Pub Date : 2020-12-22 Matthew W. Day; Mark Dong; Bradley C. Smith; Rachel C. Owen; Grace C. Kerber; Taigao Ma; Herbert G. Winful; Steven T. Cundiff
Frequency combs, broadband light sources whose spectra consist of coherent, discrete modes, have become essential in many fields. Miniaturizing frequency combs would be a significant advance in these fields, enabling the deployment of frequency-comb based devices for diverse measurement and spectroscopy applications. We demonstrate diode-laser based frequency comb generators. These laser diodes are
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High-resolution wavemeter based on polarization modulation of fiber speckles APL Photonics (IF 4.864) Pub Date : 2020-12-01 Tianliang Wang; Yi Li; Ben Xu; Bangning Mao; Yanqing Qiu; Yanlong Meng
For speckle pattern-based wavemeters or spectrometers, the intermodal and the chromatic dispersion of the diffusion waveguide are key factors in determining the wavelength resolution. In this study, we propose a new mechanism to modulate the fiber speckles aside from the dispersion related effect. The polarization modulation is introduced in a rectangular core fiber (RCF) by using an in-line polarization
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Interferometric speckle visibility spectroscopy (ISVS) for human cerebral blood flow monitoring APL Photonics (IF 4.864) Pub Date : 2020-12-04 Jian Xu; Ali K. Jahromi; Joshua Brake; J. Elliott Robinson; Changhuei Yang
Infrared light scattering methods have been developed and employed to non-invasively monitor human cerebral blood flow (CBF). However, the number of reflected photons that interact with the brain is low when detecting blood flow in deep tissue. To tackle this photon-starved problem, we present and demonstrate the idea of interferometric speckle visibility spectroscopy (ISVS). In ISVS, an interferometric
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Terahertz optical machine learning for object recognition APL Photonics (IF 4.864) Pub Date : 2020-12-08 B. Limbacher; S. Schoenhuber; M. Wenclawiak; M. A. Kainz; A. M. Andrews; G. Strasser; J. Darmo; K. Unterrainer
We demonstrate an optical machine learning method in the terahertz domain, which allows the recognition of objects within a single measurement. As many materials are transparent in the terahertz spectral region, objects hidden within such materials can be identified. In contrast to typical object recognition methods, our method only requires a single pixel detector instead of a focal plane array. The
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Probing microcavity switching events on the picosecond time scale using quantum dots as a broadband internal fluorescent source APL Photonics (IF 4.864) Pub Date : 2020-12-10 Tobias Sattler; Guilherme Monteiro Torelly; Emanuel Peinke; Arthur Gérard; Julien Claudon; Joël Bleuse; Patricia Lustoza Souza; Jean-Michel Gérard
We report on ultrafast all-optical switching experiments performed on pillar microcavities containing a collection of quantum dots (QDs). Using QDs as a broadband internal light source and a detection setup based on a streak camera, we track in parallel the frequencies of a large set (>10) of resonant modes of an isolated micropillar during the entire duration of switching events and with a 2 ps temporal
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3D side-scattering imaging flow cytometer and convolutional neural network for label-free cell analysis APL Photonics (IF 4.864) Pub Date : 2020-12-16 Rui Tang; Zunming Zhang; Xinyu Chen; Lauren Waller; Alex Ce Zhang; Jiajie Chen; Yuanyuan Han; Cheolhong An; Sung Hwan Cho; Yu-Hwa Lo
Compared with conventional fluorescence biomarker labeling, the classification of cell types based on their stain-free morphological characteristics enables the discovery of a new biological insight and simplifies the traditional cell analysis workflow. Most artificial intelligence aided image-based cell analysis methods primarily use transmitted bright-field images or holographic images. Here, we
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VO2nanophotonics APL Photonics (IF 4.864) Pub Date : 2020-11-13 Sébastien Cueff; Jimmy John; Zhen Zhang; Jorge Parra; Jianing Sun; Régis Orobtchouk; Shriram Ramanathan; Pablo Sanchis
The intriguing physics of vanadium dioxide (VO2) makes it not only a fascinating object of study for fundamental research on solid-state physics but also an attractive means to actively modify the properties of integrated devices. In particular, the exceptionally large complex refractive index variation produced by the insulator-to-metal transition of this material opens up interesting opportunities
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Dispersion engineering of superconducting waveguides for multi-pixel integration of single-photon detectors APL Photonics (IF 4.864) Pub Date : 2020-11-09 Ali W. Elshaari; Adrian Iovan; Samuel Gyger; Iman Esmaeil Zadeh; Julien Zichi; Lily Yang; Stephan Steinhauer; Val Zwiller
We use dispersion engineering to control the signal propagation speed in the feed lines of superconducting single-photon detectors. Using this technique, we demonstrate time-division-multiplexing of two-pixel detectors connected with a slow-RF transmission line, all realized using planar geometry requiring a single lithographic step. Through studying the arrival time of detection events in each pixel
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Analysis of real-time spectral interference using a deep neural network to reconstruct multi-soliton dynamics in mode-locked lasers APL Photonics (IF 4.864) Pub Date : 2020-11-02 Caiyun Li; Jiangyong He; Ruijing He; Yange Liu; Yang Yue; Weiwei Liu; Luhe Zhang; Longfei Zhu; Mengjie Zhou; Kaiyan Zhu; Zhi Wang
The dynamics of optical soliton molecules in ultrafast lasers can reveal the intrinsic self-organized characteristics of dissipative systems. The photonic time-stretch dispersive Fourier transformation (TS-DFT) technology provides an effective method to observe the internal motion of soliton molecules real time. However, the evolution of complex soliton molecular structures has not been reconstructed
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Frequency comb generation threshold via second-harmonic excitation inχ(2)optical microresonators APL Photonics (IF 4.864) Pub Date : 2020-11-02 Jan Szabados; Boris Sturman; Ingo Breunig
We investigate the threshold of χ(2) frequency comb generation in lithium niobate whispering gallery microresonators theoretically and experimentally. When generating a frequency comb via second-harmonic excitation, also commonly known as second-harmonic generation, the threshold for the onset of cascaded second-order processes leading to a comb is found to be ∼85 µW. The second-harmonic generation
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Low-loss low thermo-optic coefficient Ta2O5on crystal quartz planar optical waveguides APL Photonics (IF 4.864) Pub Date : 2020-11-05 Qiancheng Zhao; Ryan O. Behunin; Peter T. Rakich; Nitesh Chauhan; Andrei Isichenko; Jiawei Wang; Chad Hoyt; Chad Fertig; Mu hong Lin; Daniel J. Blumenthal
Optical resonator-based frequency stabilization plays a critical role in ultra-low linewidth laser emission and precision sensing, atom clocks, and quantum applications. However, there has been limited success in translating traditional bench-top stabilization cavities to compact on-chip integrated waveguide structures that are compatible with photonic integration. The challenge lies in realizing waveguides
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Combining Stokes and anti-Stokes interactions to achieve ultra-low noise dynamic Brillouin strain sensing APL Photonics (IF 4.864) Pub Date : 2020-11-11 Joseph B. Murray; Brandon Redding
Brillouin based fiber sensors are susceptible to a range of technical and environmental noise sources that can degrade the sensor performance or introduce unacceptable levels of crosstalk. Here, we introduce a new measurand that combines information from the complex Stokes and anti-Stokes interactions to extract the Brillouin frequency shift while suppressing noise and crosstalk originating from fluctuations
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CMOS-compatible all-dielectric metalens for improving pixel photodetector arrays APL Photonics (IF 4.864) Pub Date : 2020-11-13 E. Mikheeva; J.-B. Claude; M. Salomoni; J. Wenger; J. Lumeau; R. Abdeddaim; A. Ficorella; A. Gola; G. Paternoster; M. Paganoni; E. Auffray; P. Lecoq; S. Enoch
Metasurfaces and, in particular, metalenses have attracted large interest and enabled various applications in the near-infrared and THz regions of the spectrum. However, the metalens design in the visible range stays quite challenging due to the smaller nanostructuring scale and the limited choice of lossless CMOS-compatible materials. We develop a simple yet efficient design of a polarization-independent
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Planarized spatially-regular arrays of spectrally uniform single quantum dots as on-chip single photon sources for quantum optical circuits APL Photonics (IF 4.864) Pub Date : 2020-11-20 Jiefei Zhang; Qi Huang; Lucas Jordao; Swarnabha Chattaraj; Siyuan Lu; Anupam Madhukar
A long standing obstacle to realizing highly sought on-chip monolithic solid state quantum optical circuits has been the lack of a starting platform comprising scalable spatially ordered and spectrally uniform on-demand single photon sources (SPSs) buried under a planar surface. In this paper, we report on the first realization of planarized SPS arrays based on a unique class of shape-controlled single
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Alumina coating for dispersion management in ultra-high Q microresonators APL Photonics (IF 4.864) Pub Date : 2020-11-20 Marvyn Inga; Laís Fujii; José Maria C. da Silva Filho; João Henrique Quintino Palhares; Andre Santarosa Ferlauto; Francisco C. Marques; Thiago P. Mayer Alegre; Gustavo Wiederhecker
Silica optical microspheres often exhibit ultra-high quality factors, yet their group velocity dispersion, which is crucial for nonlinear optics applications, can only be coarsely tuned. We experimentally demonstrate that group-velocity dispersion of a silica microsphere can be engineered by coating it with conformal nanometric layers of alumina yet preserving its ultra-high optical quality factors
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A universal framework for microscope sensorless adaptive optics: Generalized aberration representations APL Photonics (IF 4.864) Pub Date : 2020-10-05 Q. Hu; J. Wang; J. Antonello; M. Hailstone; M. Wincott; R. Turcotte; D. Gala; M. J. Booth
Adaptive optics (AO) methods are widely used in microscopes to improve image quality through correction of phase aberrations. A range of wavefront-sensorless AO schemes exist, such as modal, pupil segmentation zonal, and pixelated piston-based methods. Each of these has a different physical implementation that makes direct comparisons difficult. Here, we propose a framework that fits in all sensorless
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An optical chip for self-testing quantum random number generation APL Photonics (IF 4.864) Pub Date : 2020-10-07 Nicolò Leone; Davide Rusca; Stefano Azzini; Giorgio Fontana; Fabio Acerbi; Alberto Gola; Alessandro Tontini; Nicola Massari; Hugo Zbinden; Lorenzo Pavesi
We present an implementation of a semi-device-independent protocol of the generation of quantum random numbers in a fully integrated silicon chip. The system is based on a prepare-and-measure scheme, where we integrate a partially trusted source of photons and an untrusted single photon detector. The source is a silicon photomultiplier, which emits photons during the avalanche impact ionization process
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Silicon nitride chirped spiral Bragg grating with large group delay APL Photonics (IF 4.864) Pub Date : 2020-10-09 Zhenmin Du; Chao Xiang; Tingzhao Fu; Minghua Chen; Sigang Yang; John E. Bowers; Hongwei Chen
As one of the most important optical filtering devices, Bragg gratings have been extensively used in various systems. A long Bragg grating is desired for many applications including frequency selection in semiconductor lasers and dispersion control for ultra-short pulses. As a prominent example, integrated spiral Bragg grating waveguides (SBGWs) have drawn much attention in the years. However, until
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Nanophotonic source of quadrature squeezing via self-phase modulation APL Photonics (IF 4.864) Pub Date : 2020-10-12 Robert Cernansky; Alberto Politi
Squeezed light is optical beams with variance below the shot noise level. They are a key resource for quantum technologies based on photons, and they can be used to achieve better precision measurements and improve security in quantum key distribution channels and as a fundamental resource for quantum computation. Here, we demonstrate an integrated source of squeezing based on four-wave mixing that
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Perfectly absorbing dielectric metasurfaces for photodetection APL Photonics (IF 4.864) Pub Date : 2020-10-20 Oleg Mitrofanov; Lucy L. Hale; Polina P. Vabishchevich; Ting Shan Luk; Sadhvikas J. Addamane; John L. Reno; Igal Brener
Perfect absorption of light by an optically thin metasurface is among several remarkable optical functionalities enabled by nanophotonics. This functionality can be introduced into optoelectronic devices by structuring an active semiconductor-based element as a perfectly absorbing all-dielectric metasurface, leading to improved optical properties while simultaneously providing electrical conductivity
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Quantum dot single-photon emission coupled into single-mode fibers with 3D printed micro-objectives APL Photonics (IF 4.864) Pub Date : 2020-10-01 Lucas Bremer; Ksenia Weber; Sarah Fischbach; Simon Thiele; Marco Schmidt; Arsenty Kaganskiy; Sven Rodt; Alois Herkommer; Marc Sartison; Simone Luca Portalupi; Peter Michler; Harald Giessen; Stephan Reitzenstein
User-friendly single-photon sources with high photon-extraction efficiency are crucial building blocks for photonic quantum applications. For many of these applications, such as long-distance quantum key distribution, the use of single-mode optical fibers is mandatory, which leads to stringent requirements regarding the device design and fabrication. We report on the on-chip integration of a quantum
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Terahertz transient stimulated emission from doped silicon APL Photonics (IF 4.864) Pub Date : 2020-10-01 S. G. Pavlov; N. Deßmann; A. Pohl; R. Kh. Zhukavin; T. O. Klaassen; N. V. Abrosimov; H. Riemann; B. Redlich; A. F. G. van der Meer; J.-M. Ortega; R. Prazeres; E. E. Orlova; A. V. Muraviev; V. N. Shastin; H.-W. Hübers
Transient-type stimulated emission in the terahertz (THz) frequency range has been achieved from phosphorus doped silicon crystals under optical excitation by a few-picosecond-long pulses generated by the infrared free electron lasers FELIX and CLIO. The analysis of the lasing threshold and emission spectra indicates that the stimulated emission occurs due to combined population inversion based lasing
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High-power few-cycle THz generation at MHz repetition rates in an organic crystal APL Photonics (IF 4.864) Pub Date : 2020-10-05 Tobias Olaf Buchmann; Edmund John Railton Kelleher; Mojca Jazbinsek; Binbin Zhou; Jin-Hong Seok; O-Pil Kwon; Fabian Rotermund; Peter Uhd Jepsen
Ultrafast terahertz (THz) spectroscopy is a potent tool for studying the fundamental properties of matter. Limitations of current THz sources, however, preclude the technique being applied in certain advanced configurations or in the measurement of, e.g., strongly absorbing samples. In response to this problem, here we demonstrate the generation of 1.38 mW broadband THz radiation at 10 MHz repetition
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Reciprocity-induced symmetry in the round-trip transmission through complex systems APL Photonics (IF 4.864) Pub Date : 2020-10-07 Szu-Yu Lee; Vicente J. Parot; Brett E. Bouma; Martin Villiger
Reciprocity is a fundamental principle of wave physics and directly relates to the symmetry in the transmission through a system when interchanging the input and output. The coherent transmission matrix (TM) is a convenient method to characterize wave transmission through general media. Here, we demonstrate the optical reciprocal nature of complex media by exploring their TM properties. We measured
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High-Q, directional and self-assembled random laser emission using spatially localized feedback via cracks APL Photonics (IF 4.864) Pub Date : 2020-10-08 Itir Bakis Dogru-Yuksel; Mertcan Han; Gregor Pirnat; Emir Salih Magden; Erkan Senses; Matjaž Humar; Sedat Nizamoglu
Lasers based on Fabry–Pérot or whispering gallery resonators generally require complex fabrication stages and sensitive alignment of cavity configurations. The structural defects on reflective surfaces result in scattering and induce optical losses that can be detrimental to laser performance. On the other hand, random lasers can be simply obtained by forming disordered gain media and scatterers, but
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Tubular optical microcavities based on rolled-up photonic crystals APL Photonics (IF 4.864) Pub Date : 2020-10-12 Rémi Briche; Aziz Benamrouche; Pierre Cremillieu; Philippe Regreny; Jean-Louis Leclercq; Xavier Letartre; Alexandre Danescu; Ségolène Callard
The self-rolling of micro-structured membranes via the stress-engineering method opens new ways to create 3D photonic micro-objects with original designs and optical properties. This article validates this approach by producing 3D hollow micro-resonators based on rolled-up 2D photonic crystal membrane mirrors, capable of trapping light in 3D and in air. We fabricated the 3D tubular microresonators
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Programmable omni-resonance using space–time fields APL Photonics (IF 4.864) Pub Date : 2020-10-12 Abbas Shiri; Kenneth L. Schepler; Ayman F. Abouraddy
Omni-resonant wave packets are pulsed optical beams that couple to planar cavities even when the wave packet bandwidth far exceeds the cavity resonant linewidth by virtue of a precise spatiotemporal structure introduced into the optical field. We demonstrate experimentally the synthesis of programmable omni-resonant wave packets in which a prescribed pulse spectrum is made to resonate with a planar
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Biomedical x-ray imaging with a GaAs photon-counting detector: A comparative study APL Photonics (IF 4.864) Pub Date : 2020-10-15 J. Scholz; L. Birnbacher; C. Petrich; M. Riedel; L. Heck; S. Gkoumas; T. Sellerer; K. Achterhold; J. Herzen
Photon-counting detectors provide several potential advantages in biomedical x-ray imaging including fast and readout noise free data acquisition, sharp pixel response, and high dynamic range. Grating-based phase-contrast imaging is a biomedical imaging method, which delivers high soft-tissue contrast and strongly benefits from photon-counting properties. However, silicon sensors commonly used in photon-counting
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Ultrafast single-shot optical vector network analyzer based on coherent time-stretch APL Photonics (IF 4.864) Pub Date : 2020-10-15 A. Lun Li; B. Liang Xu; C. Sidong Fu; D. Lei Zhang; E. Yuhua Duan; F. Yaoshuai Li; G. Ningning Yang; H. Yu Yu; I. Chi Zhang; J. Kenneth K. Y. Wong; K. Xinliang Zhang
Ever-increasing demands for a higher bandwidth of data in the optical communications augment the operating frequency of components and systems. To accelerate the development of these large-bandwidth technologies, there is a growing demand to characterize the frequency response of optical devices in real time. In this work, we report a method to significantly improve the measurement speed of an optical
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Axilenses: Refractive micro-optical elements with arbitrary exponential profiles APL Photonics (IF 4.864) Pub Date : 2020-10-21 Sergey Gorelick; David M. Paganin; Alex de Marco
We report on the experimental demonstration of refractive micro-optical elements with arbitrary exponential surface profiles. Refractive optical elements such as lenses and axicons have parabolic (power-exponent of two) or conical (power-exponent of one) surface profiles, respectively. Here, we analyze micro-optical elements with non-parabolic surface profiles characterized by both integer and fractional
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Temporal imaging with a high filling factor APL Photonics (IF 4.864) Pub Date : 2020-09-01 Avi Klein; Inbar Sibony; Sara Meir; Hamootal Duadi; Michelle Y. Sander; Moti Fridman
We demonstrate a temporal imaging system that can capture events with unknown time-of-arrival in the time domain without the need to synchronize the signal. The temporal imaging system is based on a time-lens that uses a high repetition-rate fiber laser for the pump wave together with a time-stretch scheme. After dispersion, the timing between adjacent pump pulses is smaller than the pulse width. Therefore
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Engineering photonics solutions for COVID-19 APL Photonics (IF 4.864) Pub Date : 2020-09-09 Maria Soler; Alexis Scholtz; Rene Zeto; Andrea M. Armani
As the impact of COVID-19 on society became apparent, the engineering and scientific community recognized the need for innovative solutions. Two potential roadmaps emerged: developing short-term solutions to address the immediate needs of the healthcare communities and developing mid/long-term solutions to eliminate the over-arching threat. However, in a truly global effort, researchers from all backgrounds
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Second-harmonic generation of temporally low-coherence light APL Photonics (IF 4.864) Pub Date : 2020-09-18 Xiaohui Zhao; Lailin Ji; Dong Liu; Yanqi Gao; Daxing Rao; Yong Cui; Wei Feng; Fujian Li; Haitao Shi; Chong Shan; WeiXin Ma; Zhan Sui
In this Letter, we study the second-harmonic (SH) generation of temporally low-coherence light using the statistical optics method. By introducing the statistical characteristics of low-coherence light into the nonlinear coupled wave equation, we predict the self-convolution relationship between the power spectral density of the second-harmonic and that of the fundamental wave and demonstrate it in
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High-efficiency lithium niobate modulator for K band operation APL Photonics (IF 4.864) Pub Date : 2020-09-18 Abu Naim R. Ahmed; Shouyuan Shi; Andrew Mercante; Sean Nelan; Peng Yao; Dennis W. Prather
This paper reports a hybrid silicon nitride–lithium niobate electro-optic Mach–Zehnder-interferometer modulator that demonstrates overall improvements in terms of half-wave voltage, optical insertion loss, extinction ratio, and operational bandwidth. The fabricated device exhibits a DC half-wave voltage of ∼1.3 V, a static extinction ratio of ∼27 dB, an on-chip optical loss of ∼1.53 dB, and a 3 dB
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Dynamic detection of acoustic wave generated by polarization maintaining Brillouin random fiber laser APL Photonics (IF 4.864) Pub Date : 2020-09-01 Zichao Zhou; Liang Chen; Xiaoyi Bao
The intrinsic spectral width and intensity dynamics of the acoustic wave generated by the Brillouin random fiber laser were characterized experimentally for the first time. These are important to the understanding of the dynamic noise properties of random fiber lasers based on stimulated Brillouin scattering. We demonstrate that the spectra of the acoustic wave in the gain medium are determined by
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Hyperspectral topography of the twisted, cholesteric patterns of an insect cuticle under various conditions of helix obliquity APL Photonics (IF 4.864) Pub Date : 2020-09-04 Aurélie Jullien; Maxim Neradovskiy; Michel Mitov
Twisted cholesteric liquid crystal patterns are found in the iridescent chitin-containing cuticles of many insects. They may exhibit spatial variation in the helical pitch and in the orientation of the helix axis, as in the two-band, green and silver cuticle of the scarab beetle, Chrysina gloriosa, which is the focus of the present study. The silver bands are pattern-free, whereas the green bands exhibit
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Tunable microwave-photonic filtering with high out-of-band rejection in silicon APL Photonics (IF 4.864) Pub Date : 2020-09-08 Shai Gertler; Eric A. Kittlaus; Nils T. Otterstrom; Peter T. Rakich
The ever-increasing demand for high speed and large bandwidth has made photonic systems a leading candidate for the next generation of telecommunication and radar technologies. The photonic platform enables high performance while maintaining a small footprint and provides a natural interface with fiber optics for signal transmission. However, producing sharp, narrow-band filters that are competitive
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High-performance infrared Ge-based plasmonic photodetector enhanced by dual absorption mechanism APL Photonics (IF 4.864) Pub Date : 2020-09-14 Liming Wang; Yichi Zhang; Bo Wang; Ying Wei; Bei Zhang; Lingyao Meng; Tao Liu; Bin Wang; Benguang Han; Zuimin Jiang; Huiyong Hu
A sub-wavelength plasmonic Au–Ge grating was used to enhance the responsivity of Ge-based metal–semiconductor–metal photodetectors at infrared communication wavelengths. Furthermore, a finite-difference time-domain simulation was performed to optimize absorption of light by the detectors. Characterizations of the photoelectronic properties of the optimized device revealed high-performance photodetection
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Spectral and spatial isolation of single tungsten diselenide quantum emitters using hexagonal boron nitride wrinkles APL Photonics (IF 4.864) Pub Date : 2020-09-16 Raphaël S. Daveau; Tom Vandekerckhove; Arunabh Mukherjee; Zefang Wang; Jie Shan; Kin Fai Mak; A. Nick Vamivakas; Gregory D. Fuchs
Monolayer WSe2 hosts bright single-photon emitters. Because of its compliance, monolayer WSe2 conforms to patterned substrates without breaking, thus creating the potential for large local strain, which is one activation mechanism of its intrinsic quantum emitters. Here, we report an approach to creating spatially isolated quantum emitters from WSe2 monolayers that display clean spectra with little
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Deep learning of ultrafast pulses with a multimode fiber APL Photonics (IF 4.864) Pub Date : 2020-09-17 Wen Xiong; Brandon Redding; Shai Gertler; Yaron Bromberg; Hemant D. Tagare; Hui Cao
Characterizing ultrashort optical pulses has always been a critical but difficult task, which has a broad range of applications. We propose and demonstrate a self-referenced method of characterizing ultrafast pulses with a multimode fiber. The linear and nonlinear speckle patterns formed at the distal end of a multimode fiber are used to recover the spectral amplitude and phase of an unknown pulse
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Development of site-controlled quantum dot arrays acting as scalable sources of indistinguishable photons APL Photonics (IF 4.864) Pub Date : 2020-09-17 Jan Große; Martin von Helversen; Aris Koulas-Simos; Martin Hermann; Stephan Reitzenstein
We report on the realization of an array of 28 × 28 mesas with site-controlled InGaAs quantum dots acting as single-photon sources for potential applications in photonic quantum technology. The site-selective growth of quantum dots is achieved by using the buried stressor approach where an oxide aperture serves as the nucleation site in the center of each mesa. Spectroscopic maps demonstrate the positioning
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Broadband terahertz transmissive quarter-wave metasurface APL Photonics (IF 4.864) Pub Date : 2020-09-17 Xiaolong You; Rajour T. Ako; Wendy S. L. Lee; Madhu Bhaskaran; Sharath Sriram; Christophe Fumeaux; Withawat Withayachumnankul
Polarization conversion devices are key components in spectroscopy and wireless communications systems. Conventional terahertz waveplates made of natural birefringent materials typically suffer from low efficiency, narrow bandwidth, and substantial thickness. To overcome the limitations associated with conventional waveplates, a terahertz quarter-wave metasurface with enhanced efficiency and wide bandwidth
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Ultra-low Brillouin scattering in anti-resonant hollow-core fibers APL Photonics (IF 4.864) Pub Date : 2020-09-18 Arjun Iyer; Wendao Xu; J. Enrique Antonio-Lopez; Rodrigo Amezcua Correa; William H. Renninger
Sensitive optical experiments in fiber, including for applications in communications and quantum information, are limited by the noise generated when light scatters from thermally excited guided-acoustic phonons. Novel fibers, such as microstructured fibers, offer control over both optical and acoustic waveguide properties, which can be designed to mitigate optomechanical noise. Here, we investigate
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Pulse time reversal and stopping by a refractive index front APL Photonics (IF 4.864) Pub Date : 2020-08-14 Mahmoud A. Gaafar; Jannik Holtorf; Manfred Eich; Alexander Yu. Petrov
We discuss how dynamic light stopping and pulse time reversal can be implemented in dispersive waveguides via indirect photonic transitions induced by moving refractive index fronts. The previous concepts of light stopping/time reversal either require complex local variation of the device’s refractive index or rely on the strict phase matching condition, which imposes limitations on the amount of manipulated
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Distributed Bragg reflectors for the colorimetric detection of bacterial contaminants and pollutants for food quality control APL Photonics (IF 4.864) Pub Date : 2020-08-03 Giuseppe M. Paternò; Giovanni Manfredi; Francesco Scotognella; Guglielmo Lanzani
Real-time monitoring of bacterial contaminants and pollutants in food is of paramount importance nowadays, owing to the impressive extension of the food production/supply chain and the consequent increase in foodborne outbreaks worldwide. This represents a serious risk for consumers’ health and accounts for a large fraction of food wastage, especially in the developed countries. Therefore, modern sensors
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Quantum SU(1,1) interferometers: Basic principles and applications APL Photonics (IF 4.864) Pub Date : 2020-08-10 Z. Y. Ou; Xiaoying Li
A new type of quantum interferometer was recently realized that employs parametric amplifiers (PAs) as the wave splitting and mixing elements. The quantum behavior stems from the PAs, which produce quantum entangled fields for probing the phase change signal in the interferometer. This type of quantum entangled interferometer exhibits some unique properties that are different from traditional beam
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Ultra-sensitive refractive index gas sensor with functionalized silicon nitride photonic circuits APL Photonics (IF 4.864) Pub Date : 2020-08-12 Giuseppe Antonacci; Jeroen Goyvaerts; Haolan Zhao; Bettina Baumgartner; Bernhard Lendl; Roel Baets
Portable and cost-effective gas sensors are gaining demand for a number of environmental, biomedical, and industrial applications, yet current devices are confined into specialized labs and cannot be extended to general use. Here, we demonstrate a part-per-billion-sensitive refractive index gas sensor on a photonic chip based on silicon nitride waveguides functionalized with a mesoporous silica top-cladding
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Deterministic positioning of nanophotonic waveguides around single self-assembled quantum dots APL Photonics (IF 4.864) Pub Date : 2020-08-03 T. Pregnolato; X.-L. Chu; T. Schröder; R. Schott; A. D. Wieck; A. Ludwig; P. Lodahl; N. Rotenberg
The capability to embed self-assembled quantum dots (QDs) at predefined positions in nanophotonic structures is key to the development of complex quantum-photonic architectures. Here, we demonstrate that QDs can be deterministically positioned in nanophotonic waveguides by pre-locating QDs relative to a global reference frame using micro-photoluminescence (μPL) spectroscopy. After nanofabrication,
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Coupling of quantum-well emission to waveguide–plasmon polaritons in rolled-up microtubes APL Photonics (IF 4.864) Pub Date : 2020-08-03 Hoan Vu; Jan Siebels; David Sonnenberg; Stefan Mendach; Tobias Kipp
We study the coupling of GaAs quantum wells to waveguide–plasmon polaritons supported by a thin InAlGaAs-based slab waveguide and a Ag grating. The hybrid photon–plasmon modes are excited in a freestanding emitter–waveguide–plasmon structure realized by rolling-up strained InAlGaAs-based layers and nanopatterned Ag structures. By varying the grating’s bar width, we tune the plasmonic resonance of the
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Observation of gain-pinned dissipative solitons in a microcavity laser APL Photonics (IF 4.864) Pub Date : 2020-08-04 M. Pieczarka; D. Poletti; C. Schneider; S. Höfling; E. A. Ostrovskaya; G. Sęk; M. Syperek
We demonstrate an experimental approach for creating spatially localized states in a semiconductor microcavity laser. In particular, we shape the spatial gain profile of a quasi-one-dimensional microcavity laser with a nonresonant, pulsed optical pump to create spatially localized structures, known as gain-pinned dissipative solitons, that exist due to the balance of gain and nonlinear losses. We directly
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Acousto-optic modulation in lithium niobate on sapphire APL Photonics (IF 4.864) Pub Date : 2020-08-12 Christopher J. Sarabalis; Timothy P. McKenna; Rishi N. Patel; Raphaël Van Laer; Amir H. Safavi-Naeini
We demonstrate the first acousto-optic modulators in lithium niobate films on sapphire, detailing the dependence of the piezoelectric and optomechanical coupling coefficients on the crystal orientation. This platform supports highly confined, strongly piezoelectric mechanical waves without suspensions, making it a promising candidate for broadband and efficient integrated acousto-optic devices, circuits
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Experimental realization of dual task processing with a photonic reservoir computer APL Photonics (IF 4.864) Pub Date : 2020-08-13 Jeremy Vatin; Damien Rontani; Marc Sciamanna
We experimentally demonstrate the possibility to process two tasks in parallel with a photonic reservoir computer based on a vertical-cavity surface-emitting laser (VCSEL) as a physical node with time-delay optical feedback. The two tasks are injected optically by exploiting the polarization dynamics of the VCSEL. We test our reservoir with the very demanding task of nonlinear optical channel equalization
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Direct observation of the effects of spin dependent momentum of light in optical tweezers APL Photonics (IF 4.864) Pub Date : 2020-08-20 Debapriya Pal; Subhasish Dutta Gupta; Nirmalya Ghosh; Ayan Banerjee
We demonstrate that tight focusing of a circularly polarized Gaussian beam in optical tweezers leads to spin-momentum locking—with the transverse momentum density (Poynting vector) being helicity-dependent, while the transverse spin angular momentum density becomes independent of helicity. We further use a stratified medium in the path of the trapping beam in our optical tweezers setup to enhance the
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Composed multicore fiber structure for direction-sensitive curvature monitoring APL Photonics (IF 4.864) Pub Date : 2020-07-01 Joel Villatoro; Josu Amorebieta; Angel Ortega-Gomez; Enrique Antonio-Lopez; Joseba Zubia; Axel Schülzgen; Rodrigo Amezcua-Correa
The present work deals with a curvature sensor that consists of two segments of asymmetric multicore fiber (MCF) fusion spliced with standard single mode fiber (SMF). The MCF comprises three strongly coupled cores; one of such cores is at the geometrical center of the MCF. The two segments of MCF are short, have different lengths (less than 2 cm each), and are rotated 180° with respect to each other
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Enhancing the modal purity of orbital angular momentum photons APL Photonics (IF 4.864) Pub Date : 2020-07-13 Isaac Nape; Bereneice Sephton; Yao-Wei Huang; Adam Vallés; Cheng-Wei Qiu; Antonio Ambrosio; Federico Capasso; Andrew Forbes
Orbital angular momentum (OAM) beams with topological charge ℓ are commonly generated and detected by modulating an incoming field with an azimuthal phase profile of the form exp(iℓϕ) by a variety of approaches. This results in unwanted radial modes and reduced power in the desired OAM mode. Here, we show how to enhance the modal purity in the creation and detection of classical OAM beams and in the
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Coherent fluctuations in time-domain diffuse optics APL Photonics (IF 4.864) Pub Date : 2020-07-14 Lorenzo Colombo; Saeed Samaei; Pranav Lanka; Daniele Ancora; Marco Pagliazzi; Turgut Durduran; Piotr Sawosz; Adam Liebert; Antonio Pifferi
Near infrared light pulses, multiply scattered by random media, carry useful information regarding the sample key constituents and their microstructures. Usually, the photon diffusion equation is used to interpret the data, which neglects any interference effect in the detected light fields. However, in several experimental techniques, such as diffuse correlation spectroscopy or laser speckle flowmetry
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Objective-free excitation of quantum emitters with a laser-written micro parabolic mirror APL Photonics (IF 4.864) Pub Date : 2020-07-17 Sergii Morozov; Stefano Vezzoli; Ali Hossain Khan; Iwan Moreels; Riccardo Sapienza
The efficient excitation of quantum sources such as quantum dots or single molecules requires high numerical aperture optics, which is often a challenge in cryogenics or in ultrafast optics. Here, we propose a 3.2 μm wide parabolic mirror, with 0.8 μm focal length, fabricated by direct laser writing on CdSe/CdS colloidal quantum dots, capable of focusing the excitation light to a sub-wavelength spot
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