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Using photonic devices, we developed a new approach to traditional spectroscopy where the spectral cross-correlation with a template spectrum can be done entirely on-device. By creating photonic devices with a carefully designed, modulated…

Fibre Bragg grating sensors have emerged as a simple, inexpensive, accurate, sensitive and reliable platform, a viable alternative to the traditional bulkier optical sensor platforms. In this work we present an extensive theoretical…

Optics · Physics 2015-02-18 Aliaksandr Bialiayeu

In the present article we consider an accurate modeling of spectrograph with cascade of volume-phase holographic gratings. The proposed optical scheme allows to detect spectra in an extended wavelength range without gaps providing…

Instrumentation and Methods for Astrophysics · Physics 2017-06-07 Eduard Muslimov , Gennady Valyavin , Sergei Fabrika , Nadezhda Pavlycheva

We present an optical design of astronomic spectrograph based on a cascade of volume-phase holographic gratings. The cascade consists of three gratings. Each of them provides moderately high spectral resolution in a narrow range of 83 nm.…

Instrumentation and Methods for Astrophysics · Physics 2016-08-16 Eduard R. Muslimov , Gennady G. Valyavin , Sergey N. Fabrika , Nadezhda K. Pavlycheva

We present a general analytic approach to spatially resolve the nano-scale lattice distortion field of strained and defected compact crystals with Bragg coherent x-ray diffraction imaging (BCDI). Our approach relies on fitting a…

The paper shows that silicon-based 2D photonic crystal can be a promising material for acoustooptical devices. Isotropic and anisotropic Bragg diffraction of light in photonic crystal is considered. The computational method for calculation…

Other Condensed Matter · Physics 2008-09-01 Z. A. Pyatakova

Coherent X-ray beams with energies $\geq 50$ keV can potentially enable three-dimensional imaging of atomic lattice distortion fields within individual crystallites in bulk polycrystalline materials through Bragg coherent diffraction…

We study the low frequency wave propagation behavior of sandwich beams containing periodically embedded internal resonators. A closed form expression for the propagation constant is obtained using a phased array approach and verified using…

Classical Physics · Physics 2015-12-15 Bhisham Sharma , Chin-Teh Sun

AlGaAs/GaAs coatings are being considered as coating candidates for gravitational-wave detectors. In this paper we investigate the birefringence properties of this crystalline semiconductor material by modulating the optical illumination on…

Instrumentation and Detectors · Physics 2025-12-02 Bin Wu , Shreyan Goswami , Satoshi Tanioka , Stefan Ballmer

Broadband low-resolution near-infrared spectrographs in a compact form are crucial for ground- and space-based astronomy and other fields of sensing. Astronomical spectroscopy poses stringent requirements including high efficiency, broad…

We describe a dispersive unit consisting of cascaded volume-phase holographic gratings for spectroscopic applications. Each of the gratings provides high diffractive efficiency in a relatively narrow wavelength range and transmits the rest…

Instrumentation and Methods for Astrophysics · Physics 2017-05-04 Eduard R. Muslimov , Gennady G. Valyavin , Sergei N. Fabrika , Nadezhda K. Pavlycheva

Nonlinear optical propagation in cholesteric liquid crystals (CLC) with a spatially periodic helical molecular structure is studied experimentally and modeled numerically. This periodic structure can be seen as a Bragg grating with a…

In this paper, we report the model and the experimental demonstration of a new optical resonator formed by inserting a Fiber Bragg Grating (FBG) in a closed fiber loop. The spectral characteristics of the ring depend on the reflectivity of…

Traditional Distributed Feedback (DFB) or Distributed Bragg Reflector (DBR) lasers typically utilize buried gratings as frequency-selective optical feedback mechanisms. However, the fabrication of such gratings often necessitates regrowth…

A generic modular array architecture is proposed, featuring uniform/non-uniform subarray layouts that allows for flexible deployment. The bistatic near-field sensing system is considered, where the target is located in the near-field of the…

Signal Processing · Electrical Eng. & Systems 2024-05-31 Chunwei Meng , Dingyou Ma , Xu Chen , Zhiyong Feng , Yuanwei Liu

One-dimensional (1D) polymer-based photonic crystals (PhCs) in the $1.55~\mu{}m$ wavelength range can be easily created using a two-photon direct laser writing system. To achieve shorter period structures, we report the use of thermal…

Scattering by (a) a single composite scatterer consisting of a concentric arrangement of an outer N-slit rigid cylinder and an inner cylinder which is either rigid or in the form of a thin elastic shell and (b) by a finite periodic array of…

Mathematical Physics · Physics 2011-03-11 Anton Krynkin , Olga Umnova , Alvin Y. B. Chong , Shahram Taherzadeh , Keith Attenborough

A coupling method and an analytic one allow us to prove new lower bounds for the spectral gap of reversible diffusions on compact manifolds. Those bounds are based on the a notion of curvature of the diffusion, like the coarse Ricci…

Probability · Mathematics 2011-05-31 Laurent Veysseire

We demonstrate a kind of grating coupler that generates high quality flat-top beam with a small beamwidth from photonic integrated circuits into free-space. The grating coupler is designed on a silicon-on-insulator wafer with a 220 nm-thick…

This work presents a geometric refinement of the classical Cram\'er--Rao bound (CRB) in the non-asymptotic regime by incorporating curvature-aware corrections based on the second fundamental form associated with the statistical model…

Statistics Theory · Mathematics 2026-03-11 Sunder Ram Krishnan