We have observed the nonstationary polarization modulation of a speckle pattern transmitted through a photorefractive crystal under the alternating electric field of a square-wave form. A simple model based on Gaussian-beam propagation in the crystal with the diffusion type of nonlinearity is proposed to explain the main features of the experiment. Application of the phenomenon to noncontact and highly sensitive measurements of a rough surface movement is suggested.
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http://dx.doi.org/10.1364/ol.24.000832 | DOI Listing |
ACS Mater Au
January 2025
Liquid Crystal Research Laboratory, Department of Physics, University of Lucknow, Lucknow, Uttar Pradesh 226007, India.
Polymer-dispersed liquid crystals (PDLCs) stand at the intersection of polymer science and liquid crystal technology, offering a unique blend of optical versatility and mechanical durability. These composite materials are composed of droplets of liquid crystals interspersed in a matrix of polymeric materials, harnessing the optical properties of liquid crystals while benefiting from the structural integrity of polymers. The responsiveness of LCs combined with the mechanical rigidity of polymers make polymer/LC composites-where the polymer network or matrix is used to stabilize and modify the LC phase-extremely important for scientists developing novel adaptive optical devices.
View Article and Find Full Text PDFPhys Chem Chem Phys
December 2024
MOE Key Laboratory of Weak-Light Nonlinear Photonics, TEDA Institute of Applied Physics and School of Physics, Nankai University, Tianjin 300457, China.
Lithium niobate on insulator (LNOI) has attracted widespread interest due to the excellent optical performance of lithium niobate crystals and the integration characteristics of thin film devices. With the improvement of the integration level of photonic integrated chips and the increase in light intensity inside the chip, the impact of optical damage in LNOI on-chip performance has attracted attention. One effective way to suppress the optical damage of lithium niobate is to dope it with Zr to form LiNbO (LiNbO:Zr), which is famous for its high resistance to optical damage from ultraviolet to visible spectrum.
View Article and Find Full Text PDFA dynamic holographic vibration measurement system based on a photorefractive crystal of BSO in diffuse mode without the need for an external electric field, which allows for simultaneous measurement of in-plane and out-of-plane high-frequency vibrations, is studied theoretically and experimentally in this work. By adjusting the polarization state of the reference beam, the system introduces a necessary additional phase shift of π/2 to achieve highly sensitive and linear demodulation of small phase-to-intensity vibration signals. Both theoretical analysis and experimental results confirm the system's practicality and safety, demonstrating its ability to accurately detect vibrations without the risks associated with high-voltage drift mode operation.
View Article and Find Full Text PDFPhys Rev Lett
November 2024
Department of Engineering, University of Ferrara, 44122 Ferrara, Italy.
The Kerr nonlinearity allows for exact analytic soliton solutions in 1+1D. While nothing excludes that these solitons form in naturally occurring real-world 3D settings as solitary walls or stripes, their observation had previously been considered unfeasible because of the strong transverse instability intrinsic to the extended nonlinear perturbation. We report the observation of solitons that are fully compatible with the 1+1D Kerr paradigm limit hosted in a 2+1D system.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
November 2024
State Key Laboratory of Advanced Optical Communication Systems and Networks, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China.
Topological transport is determined by global properties of physical media where it occurs and is characterized by quantized amounts of adiabatically transported quantities. Discovered for periodic potential, it was also explored in disordered and discrete quasiperiodic systems. Here, we report on experimental observation of pumping of a light beam in a genuinely continuous incommensurate photorefractive quasicrystal emulated by its periodic approximants.
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