Optical Science Research Articles

Microsphere enhanced optical imaging and patterning: From physics to applications

The diffraction limit is a fundamental barrier in optical science and engineering. It limits the minimum feature size in surface patterning technologies, such as lithography and laser direct writing. It also restricts the resolution for optical imaging, which includes different kinds of microscopes. Microspheres have been demonstrated as a powerful platform to challenge the diffraction limit. Microspheres can manipulate the light in a novel way that conventional optical components cannot achieve. In this review, we summarize the fundamental physical mechanisms and the related applications of microspheres in two primary research directions: first, to focus light energy on the sample surface, which leads to nano-patterning and achieves a sub-100 nm feature size and second, to manipulate light reflected back from the sample surface, which forms the foundation of super-resolution optical imaging to observe nano-structures. We also analyze key features, development, limitation, and opportunities of the nano-patterning and nano-imaging systems based on the microsphere.

This Was The End

In this article I describe the process of conceiving, creating and directing a performance called This Was The End, and the sound and video installation that archives it. This exploration of aging and memory has been a decade long project inspired by Uncle Vanya’s desperate thought ‘Suppose I live to be 60?’ This simple prompt lead to my collaboration with a quartet of older actors, whose careers in New York City’s downtown experimental theatre scene encompass Charles Ludlam’s Ridiculous Theatrical Company and Joe Chaiken’s Open Theater. I reflect on how their presence in the process opened up an exploration of memory on multiple fronts from the role memorization plays in conventional theater, to working with audio recordings of the actors’ memories of Chehkov’s play, to design considerations. I describe how the set, itself a recovered piece of architecture, is activated in performance with an integrated analog sound and digital video system inspired by the optical science behind Proust’s formulation of memory as the convergence of past and present. Through the scholarship of Roger Shattuck I explain how taking a Proustian approach to Chekhov’s dramatic trajectory lead to the deeper underlying question of the work - What do we do with our past? What can we make of it? Finally I consider how memorializing the fragility, resilience and persistence of these older performers as an interactive sculptural installation serves to deny erasure and remind us of a life before that continues.

Multioctave supercontinua from shock-coupled soliton self-compression

Fiber-optic multioctave supercontinuum generation is a unique resource for ultrafast optical science, enabling ultrabroadband frequency-comb technologies and paving the way for the photonics of subcycle field wave forms. Extension of these methods to the midinfrared spectral range encounters numerous challenges, calling for radically new approaches in fiber optics and short-pulse generation technologies, as well as for closing the gaps in our understanding of optical nonlinearities in the midinfrared range. Here, we confront these challenges by showing that multioctave supercontinua spanning from the ultraviolet to the midinfrared range can be generated by shock-wave-coupled soliton self-compression of ultrashort midinfrared pulses in a gas-filled antiresonance-guiding hollow-core photonic-crystal fiber. Analysis of the fiber output spectra, measured within a broad range of gas pressures and input driver energies, shows that multioctave supercontinuum generation in this setting becomes possible due to soliton self-compression coupled to shock-wave pulse self-steepening, yielding extraordinarily short, sub-half-cycle field transients.

Ultra-low-loss integrated visible photonics using thin-film lithium niobate

Integrated photonics is a powerful platform that can improve the performance and stability of optical systems, while providing low-cost, small-footprint and scalable alternatives to implementations based on free-space optics. While great progress has been made on the development of low-loss integrated photonics platforms at telecom wavelengths, visible wavelength range has received less attention. Yet, many applications utilize visible or near-visible light, including those in optical imaging, optogenetics, and quantum science and technology. Here we demonstrate an ultra-low loss integrated visible photonics platform based on thin film lithium niobate on insulator. Our waveguides feature ultra-low propagation loss of 6 dB/m, while our microring resonators have an intrinsic quality factor of 11 million, both measured at 637 nm wavelength. Additionally, we demonstrate an on-chip visible intensity modulator with an electro-optic bandwidth of 10 GHz, limited by the detector used. The ultra-low loss devices demonstrated in this work, together with the strong second- and third-order nonlinearities in lithium niobate, open up new opportunities for creating novel passive, and active devices for frequency metrology and quantum information processing in the visible spectrum range.

Laser-induced tunneling, the Kapitza effective potential, and the limits of perturbative nonlinear optics.

The canonical framework of optical physics connects the validity of perturbative nonlinear optics to the smallness of the optical driver field E compared to a characteristic field Eat that acts on electrons in an atom, a molecule, or a crystal lattice. However, in a vast area of strong-field optical science, the borderline between perturbative and nonperturbative nonlinear optics is defined as γ ~1, where γ is the Keldysh parameter. Not only is this criterion frequency-dependent, in a stark contrast with E/Eat ~1, but it also often dictates much weaker fields at which the perturbative treatment is still valid, leading to a dramatic shrinkage in the convergence radius of perturbation-theory expansions. Here, we identify the physics behind the gap between the E/Eat ~1 and γ ~1 conditions as the limits of perturbative nonlinear optics. We argue that, while the criterion E/Eat << 1 sets a universal upper-bound limit on the validity of perturbative nonlinear optics and its central concept of nonlinear-optical susceptibilities, optical nonlinearities related to photoionization pathways become nonperturbative in much weaker optical fields, with the limits of a perturbative treatment defined by the Keldysh parameter γ rather than the E/Eat ratio.

Research and practice of cooperative learning method in photoelectric technology training of college students

&lt;p&gt;Based on the constructivist learning theory, this paper adopts cooperative learning teaching method and constructs the COME science and technology education model with classroom, ideas, methods and elements as the unit according to the model of Chinese college students' physics academic competition. After more than ten years of exploration and practice by the micro-nano optical science and technology innovation team, the results show that the teaching method of combining teacher guidance and cooperative learning in the teaching of university photoelectric science and technology training not only strengthens the communication and cooperation between students, exercises students' ability to analyze and solve problems, cultivates students' cooperative consciousness, innovative spirit and scientific research quality, but also improves students' academic performance in a large area, which can definitely enhance students' knowledge, ability and quality comprehensively and harmoniously.&lt;/p&gt;

Multioctave supercontinua and subcycle lightwave electronics [Invited

Multioctave supercontinua provide a unique resource for ultrafast optical science, offering advanced tools for time-resolved spectroscopy, frequency comb technologies, nonlinear microscopy, and lightwave engineering. The physical scenarios that enable the generation of such ultrabroadband wave packets are not always easy to describe in terms of standard models of ultrafast nonlinear optics; their properties are often unusual, and their nonlinear dynamics are much more than meets the eye. To adequately understand these new electrodynamics and to identify scenarios whereby multioctave supercontinua can coherently add up yielding subcycle field waveforms, some basic concepts and models of ultrafast nonlinear optics have to be revisited. Originally intended to refer to a rapid buildup of the spectral bandwidth of ultrashort laser pulses propagating, as waveguide modes or as free beams, in media with a third-order optical nonlinearity, within the past decade, the term “supercontinuum generation” has been seamlessly extended, thanks to its all-embracing character, to include very-high-order and nonperturbative nonlinear optical processes and now applies to ultrabroadband field waveform generation in the ultraviolet and x-ray ranges, as well as high-harmonic attosecond and zeptosecond supercontinua. This paper offers a brief overview of this rapidly growing field of research.

Rapid Faraday Rotation on ε-Iron Oxide Magnetic Nanoparticles by Visible and Terahertz Pulsed Light.

Light- or electromagnetic wave-responsive magnetism is an attractive issue in spin chemistry and optical materials science. Herein we show the magnetization reversal induced by visible-light pulsed laser and the ultrafast dynamic magnetooptical effect caused by terahertz (THz) pulsed laser irradiation onto chemically synthesized magnetic films based on gallium-titanium-cobalt-substituted ε-Fe2O3 (GTC-ε-Fe2O3) and ε-Fe2O3 nanoparticles. Visible-light pulsed laser irradiation switches the sign of the Faraday effect in GTC-ε-Fe2O3 films. On the other hand, irradiating the ε-Fe2O3 film with pulsed THz light induces an ultrafast Faraday rotation in an extremely short time of 400 fs. The time evolution dynamics of these ultrafast magnetooptical effects are theoretically demonstrated by stochastic Landau-Lifshitz-Gilbert calculations of a nanoparticle model that considers all motions of the individual spins. These ε-iron oxide magnetic nanomaterials are expected to contribute to high-density magnetic memory media or high-speed operation circuit magnetic devices.

Large Rabi splitting obtained in Ag-WS2 strong-coupling heterostructure with optical microcavity at room temperature

Manipulation of light-matter interaction is critical in modern physics, especially in the strong coupling regime, where the generated half-light, half-matter bosonic quasiparticles as polaritons are important for fundamental quantum science and applications of optoelectronics and nonlinear optics. Two-dimensional transition metal dichalcogenides (TMDs) are ideal platforms to investigate the strong coupling because of their huge exciton binding energy and large absorption coefficients. Further studies on strong exciton-plasmon coupling by combining TMDs with metallic nanostructures have generated broad interests in recent years. However, because of the huge plasmon radiative damping, the observation of strong coupling is significantly limited at room temperature. Here, we demonstrate that a large Rabi splitting (~300 meV) can be achieved at ambient conditions in the strong coupling regime by embedding Ag-WS₂ heterostructure in an optical microcavity. The generated quasiparticle with part-plasmon, part-exciton and part-light is analyzed with Hopfield coefficients that are calculated by using three-coupled oscillator model. The resulted plasmon-exciton polaritonic hybrid states can efficiently enlarge the obtained Rabi splitting, which paves the way for the practical applications of polaritonic devices based on ultrathin materials.

LiDAR Packaging

The rising demand for the “eyes to the machine” or 3D point cloud images in a wide set of application areas, such as automotive, trucking, UAV/drones, industrial, mapping, military and defense, surveillance, and others, is expected to exponentially drive the LiDAR market over the next two decades. The massive automotive LiDAR market is at its nascence stage. Wallstreet Research projects a $2 billion market by 2020 and grow to a staggering $82B by 2035. The Total Available Market (TAM) of LiDAR sensors is expected to grow from hundreds of thousands to millions and hundreds of millions through this period. With the market growth in demand and application specific requirements, the design, manufacturing and proxy of performance must revolutionize to deliver performance, quality, reliability, scale and cost. LiDAR optical design, integration, and miniaturization require novel packaging solutions, process and advanced tool development and hands-on lessons. Packaging and validation of performance requires a multidisciplinary approach that spans across the optical, electrical, mechanical and computer science domains. Although LiDAR has been around since the 1960s, the industry is beginning to learn the challenges in semiconductor packaging, interconnect substrate technologies, optoelectronic module technology, inter-assembly, and manufacturing multichip modules to meet the needs of the autonomous machine market.

特集：眼光学の眼科医療への応用 手術顕微鏡への応用

特集：眼光学の眼科医療への応用 手術顕微鏡への応用

Comparative study of sampling moiré and windowed Fourier transform techniques for demodulation of a single-fringe pattern.

Phase measurement techniques using a single-shot carrier fringe pattern play an important role in optical science and technology and have been widely used for various applications. In this paper, we focus on the comparative study of two major fringe analysis techniques, the sampling moiré (SM) and the windowed Fourier transform (WFT). While SM converts a single-fringe pattern to multiple phase-shifted moiré fringe patterns to extract the phase information in the spatial domain, WFT obtains the phase information in the windowed Fourier domain; thus, the two methods look entirely different. We evaluate the phase extraction errors of SM and windowed Fourier ridges (WFRs) as a typical WFT method for both linear and nonlinear phases with/without noise against the reference Fourier transform (FT) technique. For the simulated fringe patterns with linear or nonlinear phase and different random noise level, all the methods have high phase extraction accuracies. For a real experiment with more complicated phase and discontinuities, SM and WFR, both local methods, yield quite similar results and outperform FT.

The European optical contribution to the James Webb Space Telescope

Abstract The James Webb Space Telescope (JWST) is frequently referred to as the follow-on mission to the Hubble Space Telescope (HST). The ‘Webb’ will be the biggest space telescope ever built and is expected to enable astounding new science. The observatory comprises a 6.5-m-diameter telescope with a segmented primary mirror and four high-performance optical science instruments. The JWST has mostly been optimized to work in the near- (0.6–5.0 μm) and mid-infrared (5.0–29 μm) wavelength regions. The project is a strong international partnership led by the National Aeronautics and Space Administration (NASA) with contributions from the European Space Agency (ESA) and the Canadian Space Agency (CSA). The observatory is currently scheduled for launch in early 2021 from Kourou, French Guyana, by an ESA-provided Ariane 5 rocket. This paper will focus on the European optical contribution to the mission, which mainly consists of two highly advanced optical science instruments: The multi-object near-infrared spectrograph (NIRSpec) and the mid-infrared instrument (MIRI). The opto-mechanical design considerations and the realization of both instruments will be described, and we will conclude with a short JWST project status report and future outlook.

Relationships between Learning Coaching and Self-directed Learning and academie Achievement of Students in the Department of Optometry and Optics Science at a university

Relationships between Learning Coaching and Self-directed Learning and academie Achievement of Students in the Department of Optometry and Optics Science at a university

IR and UV/VIS Spectroscopic Characterization of the Higher Fullerene C76-D2 for Its Quantitative and Qualitative Determination

The only stable isomer of the higher fullerene C76 of D2 symmetry was isolated from carbon soot by the new and advanced extraction and chromatographic methods and processes. Characterization of the isolated C76-D2 was performed by the IR(KBr) and UV/VIS method in the absorption mode. All of the experimentally observed infrared and electronic absorption bands are in excellent agreement with the theoretical calculations for this fullerene. The molar absorptivity ε and the integrated molar absorptivity Ψ of the observed entire new series of various characteristic, both deconvoluted and convoluted IR absorption bands of the C76-D2 isomer, in different integration ranges were determined. In addition, the molar extinction coefficients of its UV/VIS absorption bands were determined. The obtained novel IR and UV/VIS spectroscopic parameters are significant for the quantitative assessment of C76-D2. All the presented data are important both for its qualitative and quantitative determination, either in natural resources on Earth and in space or in artificially synthesized materials, electronic and optical devices, optical limiters, sensors, polymers, solar cells, nanophotonic lenses, diagnostic and therapeutic agents, pharmaceutical substances, for targeted drug delivery, incorporation of metal atoms, in biomedical engineering, industry, applied optical science, batteries, catalysts and so forth.

Measurements of Speckle Lifetimes in Near-infrared Extreme Adaptive Optics Images for Optimizing Focal Plane Wavefront Control

Although extreme adaptive optics (ExAO) systems can greatly reduce the effects of atmospheric turbulence and deliver diffraction-limited images, our ability to observe faint objects such as extrasolar planets or debris disks at small angular separations is greatly limited by the presence of a speckle halo caused by imperfect wavefront corrections. These speckles change with a variety of timescales, from milliseconds to many hours, and various techniques have been developed to mitigate them during observations and during data reduction. Detection limits improve with increased speckle reduction, so an understanding of how speckles evolve (particularly at near-infrared wavelengths, which is where most adaptive optics science instruments operate) is of distinct interest. We used a SAPHIRA detector behind Subaru Telescope’s SCExAO instrument to collect H-band images of the ExAO-corrected point-spread function (PSF) at a frame rate of 1.68 kHz. We analyzed these images using two techniques to measure the timescales over which the speckles evolved. In the first technique, we analyzed the images in a manner applicable to predicting performance of real-time speckle-nulling loops. We repeated this analysis using data from several nights to account for varying weather and AO conditions. In our second analysis, which follows the techniques employed by Milli et al. () but using data with three orders of magnitude better temporal resolution, we identified a new regime of speckle behavior that occurs at timescales of milliseconds. It is not purely an instrument effect and likely is an atmospheric timescale filtered by the ExAO response. We also observed an exponential decay in the Pearson’s correlation coefficients (which we employed to quantify the change in speckles) on timescales of seconds and a linear decay on timescales of minutes, which is in agreement with the behavior observed by Milli et al. For both of our analyses, we also collected similar data sets using SCExAO’s internal light source to separate atmospheric effects from instrumental effects.

Identification of Ge vacancies as electronic defects in methyl- and hydrogen-terminated germanane

We use a combination of optical and electrostatic surface science techniques to measure electronically active native defects in multilayer GeCH3 and GeH, two-dimensional (2D) functionalized materials. Chemical processing techniques coupled with density functional theory enable us to identify the specific physical nature of both native point defects and synthesis-related impurities which can limit the optical and charge transport properties of these materials. Direct comparison of optical measurements with calculated electronic levels provides identification of these localized, deep level gap states and confirms partial H-passivation of dangling bonds, revealing synthesis and processing methods needed to control specific defects and optimize these 2D materials for emergent solid state-electronics.

Ultraflexible Near-Infrared Organic Photodetectors for Conformal Photoplethysmogram Sensors.

Flexible organic optoelectronic devices simultaneously targeting mechanical conformability and fast responsivity in the near-infrared (IR) region are a prerequisite to expand the capabilities of practical optical science and engineering for on-skin optoelectronic applications. Here, an ultraflexible near-IR responsive skin-conformal photoplethysmogram sensor based on a bulk heterojunction photovoltaic active layer containing regioregular polyindacenodithiophene-pyridyl[2,1,3]thiadiazole-cyclopentadithiophene (PIPCP) is reported. The ultrathin (3 µm thick) photodetector exhibits unprecedented operational stability under severe mechanical deformation at a bending radius of less than 3 µm, even after more than 103 bending cycles. Deliberate optimization of the physical dimensions of the active layer used in the device enables precise on/off switching and high device yield simultaneously. The response frequency over 1 kHz under mechanically deformed conditions facilitates conformal electronic sensors at the machine/human interface. Finally, a mechanically stretchable, flexible, and skin-conformal photoplethysmogram (PPG) device with higher sensitivity than those of rigid devices is demonstrated, through conformal adherence to the flexuous surface of a fingerprint.

Erratum to: Study on the effect of ellipticity and misalignment on OAM modes in a ring fiber

In the originally published article the affiliation was incorrect and should be corrected From: Key Laboratory of Optical Communications Science and Technology in Shandong Province, School of Physics Science and Information Technology, Liaocheng 252059, China To: Key Laboratory of Optical Communications Science and Technology in Shandong Province, School of Physics Science and Information Technology, Liaocheng University, Liaocheng 252059, China Added: “Liaocheng University”

Arabic classical traditions in the history of the exact sciences: The case of Ibn al-Haytham⋆

This paper examines selected leitmotifs from the Arabic classical traditions in the history of the exact sciences while taking into account their adaptive assimilation and expansion of ancient Greek scientific knowledge within the pre-modern Islamicate intellectual milieu, and the subsequent transmission and reception of the Greco-Arabic sciences within the European mediaeval and Renaissance circles of scholarship. To give a more concrete focus to this thematic orientation I will address the legacy in the science of optics of the 11th century Arab polymath al-Hasan Ibn al-Haytham (known in Latin renditions of his name as Alhazen; died ca. 1041 CE), as encompassed primarily in his Kitāb al-manāzir (Book of Optics, De aspectibus or Perspectiva). This opus contained his explications of the nature and comportment of light and direct vision, including studies in catoptrics and dioptrics (respectively, the optical sciences that investigate the mathematical and physical principles of the reflection and refraction of light, along with their associated scientific instruments). This inquiry is situated within the wider epistemic setting of Ibn al-Haytham’s scientific experimental method of controlled testing that is underpinned by an isomorphic composition of geometric modelling with physics in studying natural phenomena.