Hasil untuk "Optics. Light"

N. Yu, F. Capasso

D. Malacara-hernández

S. Popoff, G. Lerosey, R. Carminati et al.

We introduce a method to experimentally measure the monochromatic transmission matrix of a complex medium in optics. This method is based on a spatial phase modulator together with a full-field interferometric measurement on a camera. We determine the transmission matrix of a thick random scattering sample. We show that this matrix exhibits statistical properties in good agreement with random matrix theory and allows light focusing and imaging through the random medium. This method might give important insight into the mesoscopic properties of a complex medium.

L. Mandel, E. Wolf

C. Bohren, D. Huffman

Hao Wang, Wang Zhang, D. Ladika et al.

The rapid development of additive manufacturing has fueled a revolution in various research fields and industrial applications. Among the myriad of advanced 3D printing techniques, two‐photon polymerization lithography (TPL) uniquely offers a significant advantage in nanoscale print resolution, and has been widely employed in diverse fields, for example, life sciences, materials sciences, mechanics, and microfluidics. More recently, by virtue of the optical transparency of most of the resins used, TPL is finding new applications in optics and photonics, with nanometer to millimeter feature dimensions. It enables the minimization of optical elements and systems, and exploration of light‐matter interactions with new degrees of freedom, never possible before. To review the recent progress in the TPL related optical research, it starts with the fundamentals of TPL and material formulation, then discusses novel fabrication methods, and a wide range of optical applications. These applications notably include diffractive, topological, quantum, and color optics. With a panoramic view of the development, it is concluded with insights and perspectives of the future development of TPL and related potential optical applications.

F. Dirnberger, Jiamin Quan, R. Bushati et al.

Controlling quantum materials with light is of fundamental and technological importance. By utilizing the strong coupling of light and matter in optical cavities^ 1 – 3 , recent studies were able to modify some of their most defining features^ 4 – 6 . Here we study the magneto-optical properties of a van der Waals magnet that supports strong coupling of photons and excitons even in the absence of external cavity mirrors. In this material—the layered magnetic semiconductor CrSBr—emergent light–matter hybrids called polaritons are shown to substantially increase the spectral bandwidth of correlations between the magnetic, electronic and optical properties, enabling largely tunable optical responses to applied magnetic fields and magnons. Our results highlight the importance of exciton–photon self-hybridization in van der Waals magnets and motivate novel directions for the manipulation of quantum material properties by strong light–matter coupling. In the layered magnetic semiconductor CrSBr, emergent light–matter hybrids (polaritons) increase the spectral bandwidth of correlations between the magnetic, electronic and optical properties, enabling largely tunable optical responses to applied magnetic fields and magnons.

Shivasubramanian Gopinath, Joseph Rosen, Vijayakumar Anand

Fresnel incoherent correlation holography (FINCH) is a self-interference-based incoherent digital holography method. In FINCH, light from an object point is split into two beams, modulated differently using two lenses with different focal distances, and creates a self-interference hologram. At least three phase-shifted holograms are recorded and synthesized into a complex hologram, which reconstructs the object image without twin image and bias noises. Compared with conventional imaging, FINCH exhibits a longer depth of focus (DOF) and higher lateral resolution. In this study, we propose and demonstrate a new method termed post-engineering of axial resolution in FINCH (PEAR-FINCH), which enables post-recording DOF engineering for the first time. In PEAR-FINCH, a library of FINCH holograms catalogued with unique axial characteristics, DOF, and focus location is recorded by changing the focal distance of one of the diffractive lenses. Selected holograms from this library are combined to engineer new axial characteristics not achievable in FINCH. A two-step reconstruction, involving numerical back-propagation and deconvolution with a point spread hologram, is implemented. Experiments with multiplane objects having large axial separations confirm that PEAR-FINCH achieves a substantially extended DOF compared with direct imaging and FINCH. PEAR-FINCH will be promising for applications in biomedical imaging, holography, and fluorescence microscopy.

Xinwei Wang, Huijie Hao, Xiaoyuan He et al.

C. L. Carilli, L. Torino, B. Nikolic et al.

Wave front sensing of the surface of equal phase for a propagating electromagnetic wave is a vital technology in fields ranging from real time adaptive optics, to high accuracy metrology, to medical optometry. We have developed a new method of wavefront sensing that makes a direct measurement of the electromagnetic phase distribution, or path-length delay, across an optical wavefront. The method is based on techniques developed in radio astronomical interferometric imaging. The method employs optical interferometry using a 2-D aperture mask, a Fourier transform of the interferogram to derive interferometric visibilities, and self-calibration of the complex visibilities to derive the voltage amplitude and phase gains at each hole in the mask, corresponding to corrections for non-uniform illumination and wavefront distortions across the aperture, respectively. The derived self-calibration gain phases are linearly proportional to the electromagnetic path-length distribution to each hole in the aperture mask, relative to the path-length to the reference hole, and hence represent a wavefront sensor with a precision of a small fraction of a wavelength. The method was tested at $λ=400\,$nm at the Xanadu optical bench at the ALBA synchrotron light source using a rotating mirror to insert tip-tilt changes in the wavefront. We reproduce the wavefront tilts to within $0.1''$ ($5\times 10^{-7}$~radians). We also derive the static metrology though the optical system for non-planar wavefront distortions to $\sim \pm1$~nm repeatability. Lastly, we derive frame-to-frame variations of the wavefront tilt due to vibrations of the optical components which range up to $\sim 0.5"$. These variations are relevant to adaptive optics applications. Based on the measured visibility phase noise after self-calibration, we estimate an rms path-length precision per 1~ms exposure of 0.6 nm.

Augustine A. McAsule, Ngutor S. Akiiga, Joshua S. Ikwe et al.

Shiqi Feng, Xuquan Wang, Xiong Dun et al.

Encoded computational hyperspectral cameras, propelled by advances in compressed sensing theory, making both miniaturization and real-time hyperspectral imaging feasible. Spectral-encoded or spatial-encoded hyperspectral imaging strategy have limited numbers of design parameters in optical components, leading to severe ill-posedness in hyperspectral images reconstruction, which constrain overall imaging quality. However, spatial-spectral-encoded hyperspectral imaging strategy which simultaneously performs spatial and spectral encoding entailing more powerful modulation, alleviating ill-posed problems and improving the quality of hyperspectral images. In this paper, we present a co-modulation framework based on diffractive optical element (DOE) and Superposition Fabry&#x2013;Perot (SFP) filter array for computational hyperspectral camera that integrates these two components with a transformer-based reconstruction network through end-to-end learning. The learned DOE and SFP filter encode the hyperspectral datacube on the sensor via phase and amplitude modulation, and the transformer-based network accurately reconstructs the images from sensor measurements. We conduct extensive simulations to analyze and validate the relatively contributions of the DOE, SFP filter, and transformer-based reconstruction algorithm to the significantly improved performance of hyperspectral image reconstruction across various ablation study models. We further investigate and identify the <inline-formula><tex-math notation="LaTeX">$\mathbf {4\times 4}$</tex-math></inline-formula> SFP filter unit configuration as the most effective design for achieving a balance between spectral fidelity and spatial resolution. Our results show that the proposed system outperforms state-of-the-art methods in hyperspectral images reconstruction quality, excelling in both spatial and spectral detail recovery, and maintaining good performance against realistic noise levels.

P. Lalanne, M Chen, C. Rockstuhl et al.

Optical metasurfaces are conventionally viewed as organized flat arrays of photonic or plasmonic nanoresonators, also called metaatoms. These metasurfaces are typically highly ordered and fabricated with precision using expensive tools. However, the inherent imperfections in large-scale nanophotonic devices, along with recent advances in bottom-up nanofabrication techniques and design strategies, have highlighted the potential benefits of incorporating disorder to achieve specific optical functionalities. This review offers an overview of the key theoretical, numerical, and experimental aspects related to the exploration of disordered optical metasurfaces. It introduces fundamental concepts of light scattering by disordered metasurfaces and outlines theoretical and numerical methodologies for analyzing their optical behavior. Various fabrication techniques are discussed, highlighting the types of disorder they deliver and their achievable precision level. The review also explores critical applications of disordered optical metasurfaces, such as light manipulation in thin film materials and the design of structural colors and visual appearances. Finally, the article offers perspectives on the burgeoning future research in this field. Disordered optical metasurfaces offer a promising alternative to their ordered counterparts, often delivering unique functionalities or enhanced performance. They present a particularly exciting opportunity in applications demanding large-scale implementation, such as sustainable renewable energy systems, as well as aesthetically vibrant coatings for luxury goods and architectural designs.

Chi Li, Haoran Ren

Abstract A see-through augmented reality prototype has been developed based on an ultrathin nanoimprint metalens array, opening up a full-colour, video-rate, and low-cost 3D near-eye display.

Nicolas Maron, Sébastien Fernandez, François-Xavier Esnault et al.

We present the results of an optical link to a corner cube on board a tethered balloon at 300 m altitude including a Tip/Tilt compensation for the balloon tracking. Our experiment measures the carrier phase of a 1542 nm laser, which is the useful signal for frequency comparison of distant clocks. An active phase noise compensation of the carrier is implemented, demonstrating a fractional frequency stability of 8x10-19 after 16 s averaging, which slightly (factor ~3) improves on best previous links via an airborne platform. This state-of-the-art result is obtained with a transportable set-up that enables a fast field deployment.

R.R. Diyazitdinov

In this article, we describe an iterative algorithm for accurate superposition of contours with non-uniform sampling step. The processing contours are characterized by the same shape, but the sampling step is non-uniform, with no matching between points of the superposed contours. This makes impossible the use of methods for estimating superposition parameters by matching points. The algorithm proposed herein allows estimating the offsets and rotation angle separately. The idea of the algorithm is to perform the iterative correction of parameters. An estimate of the offsets is used to estimate the rotation angle and, vice versa, an estimate of the rotation angle is used to estimate the offsets. The proposed algorithm is characterized by a higher speed of processing than a brute force algorithm and a lower estimation error than algorithms that analyze contour macroparameters.

R. Ruska, B. Berzina, J. Cipa et al.

Luminescence processes resulting in 600 nm emission of Mn2+ ions in AlN:Mn ceramics were studied based on investigations of photoluminescence and its excitation spectra, luminescence kinetics and long-lasting luminescence (PersL) properties. For AlN:Mn2+ nanopowders, the photoluminescence spectra and PersL were studied. Luminescence properties were examined and compared after the samples were irradiated with 520 nm light, resulting in direct excitation of Mn2+ ions, thus causing the intra-center luminescence, or with 263 nm light. As known, in the last case, the oxygen-related defects are primarily excited with the following energy transfer to Mn2+ ions and 600 nm emission, thus forming the recombination luminescence (RecL). Two types of excitations of the 600 nm RecL were used. In the first case, the luminescence response was detected during the sample irradiation with 263 nm light. It was found that at RT, the decay of the RecL is fast and its decay constant τ = 1.2 ms coincides with the value obtained for the intra-center luminescence. A time-dependent rise of the 600 nm luminescence intensity under 263 nm excitation was observed. In the other case, the 600 nm RecL was detected when irradiation of the sample with 263 nm light was ceased, and spectra and decay of PersL were studied. It was found that the decay of 600 nm PersL spectra could be described using three exponential functions, thus manifesting a variety of luminescence processes. The results allow tracing of the luminescence processes and proposal of the mechanisms resulting in the 600 nm light emission of Mn2+ ions. An energy level scheme of AlN:Mn2+ was constructed to elucidate of the luminescence processes and mechanisms.

Jin Woo Oh, Seokyeong Lee, Hyowon Han et al.

Abstract Optical encryption technologies based on room-temperature light-emitting materials are of considerable interest. Herein, we present three-dimensional (3D) printable dual-light-emitting materials for high-performance optical pattern encryption. These are based on fluorescent perovskite nanocrystals (NCs) embedded in metal-organic frameworks (MOFs) designed for phosphorescent host-guest interactions. Notably, perovskite-containing MOFs emit a highly efficient blue phosphorescence, and perovskite NCs embedded in the MOFs emit characteristic green or red fluorescence under ultraviolet (UV) irradiation. Such dual-light-emitting MOFs with independent fluorescence and phosphorescence emissions are employed in pochoir pattern encryption, wherein actual information with transient phosphorescence is efficiently concealed behind fake information with fluorescence under UV exposure. Moreover, a 3D cubic skeleton is developed with the dual-light-emitting MOF powder dispersed in 3D-printable polymer filaments for 3D dual-pattern encryption. This article outlines a universal principle for developing MOF-based room-temperature multi-light-emitting materials and a strategy for multidimensional information encryption with enhanced capacity and security.

M. Noda, Shunsuke A. Sato, Yuta Hirokawa et al.

Abstract SALMON (Scalable Ab-initio Light–Mattersimulator for Optics and Nanoscience, http://salmon-tddft.jp ) is a software package for the simulation of electron dynamics and optical properties of molecules, nanostructures, and crystalline solids based on first-principles time-dependent density functional theory. The core part of the software is the real-time, real-space calculation of the electron dynamics induced in molecules and solids by an external electric field solving the time-dependent Kohn–Sham equation. Using a weak instantaneous perturbing field, linear response properties such as polarizabilities and photoabsorptions in isolated systems and dielectric functions in periodic systems are determined. Using an optical laser pulse, the ultrafast electronic response that may be highly nonlinear in the field strength is investigated in time domain. The propagation of the laser pulse in bulk solids and thin films can also be included in the simulation via coupling the electron dynamics in many microscopic unit cells using Maxwell’s equations describing the time evolution of the electromagnetic fields. The code is efficiently parallelized so that it may describe the electron dynamics in large systems including up to a few thousand atoms. The present paper provides an overview of the capabilities of the software package showing several sample calculations. Program summary Program Title: SALMON: Scalable Ab-initio Light–Matter simulator for Optics and Nanoscience Program Files doi: http://dx.doi.org/10.17632/8pm5znxtsb.1 Licensing provisions: Apache-2.0 Programming language: Fortran 2003 Nature of problem: Electron dynamics in molecules, nanostructures, and crystalline solids induced by an external electric field is calculated based on first-principles time-dependent density functional theory. Using a weak impulsive field, linear optical properties such as polarizabilities, photoabsorptions, and dielectric functions are extracted. Using an optical laser pulse, the ultrafast electronic response that may be highly nonlinear with respect to the exciting field strength is described as well. The propagation of the laser pulse in bulk solids and thin films is considered by coupling the electron dynamics in many microscopic unit cells using Maxwell’s equations describing the time evolution of the electromagnetic field. Solution method: Electron dynamics is calculated by solving the time-dependent Kohn–Sham equation in real time and real space. For this, the electronic orbitals are discretized on a uniform Cartesian grid in three dimensions. Norm-conserving pseudopotentials are used to account for the interactions between the valence electrons and the ionic cores. Grid spacings in real space and time, typically 0.02 nm and 1 as respectively, determine the spatial and temporal resolutions of the simulation results. In most calculations, the ground state is first calculated by solving the static Kohn–Sham equation, in order to prepare the initial conditions. The orbitals are evolved in time with an explicit integration algorithm such as a truncated Taylor expansion of the evolution operator, together with a predictor–corrector step when necessary. For the propagation of the laser pulse in a bulk solid, Maxwell’s equations are solved using a finite-difference scheme. By this, the electric field of the laser pulse and the electron dynamics in many microscopic unit cells of the crystalline solid are coupled in a multiscale framework.

Renming Liu, Zhangkai Zhou, Yi-Cong Yu et al.

Reaching the quantum optics limit of strong light-matter interactions between a single exciton and a plasmon mode is highly desirable, because it opens up possibilities to explore room-temperature quantum devices operating at the single-photon level. However, two challenges severely hinder the realization of this limit: the integration of single-exciton emitters with plasmonic nanostructures and making the coupling strength at the single-exciton level overcome the large damping of the plasmon mode. Here, we demonstrate that these two hindrances can be overcome by attaching individual J aggregates to single cuboid Au@Ag nanorods. In such hybrid nanosystems, both the ultrasmall mode volume of ∼71  nm^{3} and the ultrashort interaction distance of less than 0.9 nm make the coupling coefficient between a single J-aggregate exciton and the cuboid nanorod as high as ∼41.6  meV, enabling strong light-matter interactions to be achieved at the quantum optics limit in single open plasmonic nanocavities.