光子学报
2023, 52(10): 1052404
光子学报
2021, 50(10): 1024001
Author Affiliations
Abstract
College of Physics Science and Information Engineering, Hebei Normal University,
We theoretically study the optimum design of anisotropic acousto-optic modulator (AOM) based on lithium niobate crystal. Four different kinds of operating modes in the XOZ and YOZ acousto-optic (AO) planes are systematically analyzed by the tangent condition theory and the optimized operating mode is determined. Furthermore, the dependence of the AO merit on the operating frequency and the off-axis angle of the AOM are also obtained by numerical simulations.
160.1190 Anisotropic optical materials 170.1065 Acousto-optics 230.1040 Acousto-optical devices 230.4110 Modulators Chinese Optics Letters
2015, 13(s1): S11601
Author Affiliations
Abstract
College of Physics Science and Information Engineering, Hebei Normal University, Shijiazhuang 050024, China
We present theoretical studies on the wideband design of bulk lithium niobate (LN) acousto-optic deflector (AOD) through the walk-off design of the ultrasonic vector, which satisfies the momentum match condition. The ultrasonic properties of LN crystal are studied by solving the Christopher equation and the reciprocal velocity curves in the operating planes XOZ and YOZ are systematically obtained. The calculation results show that the bandwidth of the AOD is highly dependent on the incident angle of light beam and the velocity of the ultrasonic waves, which show strict linear properties in the operating bandwidth. Furthermore, the dependence of the central frequency of the AOD on the angle of incident light and the ultrasonic velocity are also analyzed.
160.1050 Acousto-optical materials 170.1065 Acousto-optics 160.1190 Anisotropic optical materials Chinese Optics Letters
2014, 12(s2): S21601
Author Affiliations
Abstract
A planar-hyperlens-based imaging device is presented in this paper. Based on the structure of hyperbolic dispersion metamaterial and with the ability of collecting the evanescent waves from the object, the planar hyperlens can deliver and magnify the super-resolution details of a planar object to the extent that a traditional microscopic objective can resolve them. The super-resolution magnification imaging principle of the device was analyzed, and the relations of the imaging resolution and magnification with the structure parameters of the device were deduced. With careful design, the effectiveness of the device was confirmed in a series of numerical simulations.
160.1190 Anisotropic optical materials 260.3910 Metal optics 350.3950 Micro-optics Chinese Optics Letters
2014, 12(s1): S11601
Author Affiliations
Abstract
Based on two-step coordinate transformation along the radial direction, an optical device with three functions is proposed. The proposed device functions as a transparent device, a vision-enabling internal cloak, and a movement-allowing external cloak. The general expressions of material parameters for the optical device are determined, and each function of the device is confirmed using full-wave simulation. The effect of material loss on device performance is also investigated. Future applications for the proposed device include antenna protection and military stealth.
160.1190 Anisotropic optical materials 160.3918 Metamaterials 260.2710 Inhomogeneous optical media Chinese Optics Letters
2013, 11(9): 091602
Author Affiliations
Abstract
Liquid Crystal Institute, Kent State University, Kent, Ohio 44242, USA
Cholesteric liquid crystals, consisting of chiral molecules, form self-assembled periodic structures exhibiting a photonic bandgap. Their selective reflectivity makes them well suited for a variety of applications; their optical response is therefore of considerable interest. The reflectance and transmittance of finite cholesteric cells is usually calculated numerically. Evanescent modes in the bandgap make the calculations challenging; existing matrix propagation methods cannot describe the reflection and transmission coefficients of thick cholesteric cells accurately. Here we present analytic solutions for the electromagnetic fields in cholesteric cells of finite thickness, and use them to calculate the transmission and reflection spectra. The use of analytic solutions allows for the accurate description of arbitrarily thick cholesteric cells, which would not be possible with only direct numerical methods.
Liquid crystals Photonic bandgap materials Birefringence Anisotropic optical materials Chiral media Photonics Research
2013, 1(1): 01000058
Author Affiliations
Abstract
Laboratory of Optical Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
Gold nanorods (GNRs) have potential applications ranging from biomedical sciences and emerging nanophotonics. In this paper, we will review some of our recent studies on both microscopic and macroscopic manipulation of GNRs. Unique properties of GNR nanoparticles, such as efficient surface plasmon amplifications effects, are introduced. The stable trapping, transferring, positioning and patterning of GNRs with nonintrusive optical tweezers will be shown. Vector beams are further employed to improve the trapping performance. On the other hand, alignment of GNRs and their hybrid nanostructures will be described by using a film stretch method, which induces the anisotropic and enhanced absorptive nonlinearities from aligned GNRs. Realization and engineering of polarized emission from aligned hybrid GNRs will be further demonstrated, with relative excitation–emission efficiency significantly enhanced. Our works presented in this review show that optical tweezers possess great potential in microscopic manipulation of metal nanoparticles and macroscopic alignment of anisotropic nanoparticles could help the macroscopic samples to flexibly represent the plasmonic properties of single nanoparticles for fast, cheap, and high-yield applications.
Optical tweezers or optical manipulation Surface plasmons Nanomaterials Anisotropic optical materials Photonics Research
2013, 1(1): 01000028
Author Affiliations
Abstract
Based on the concept of complementary media and theory of coordinate transformation, a novel kind of optical device, exhibiting the multiple performances of a complementary cloak and a transparent device, is proposed. Only the axial material parameter of the proposed device is spatially variant, and the transverse material parameters are constant. The multiple functions of the proposed device are validated by full wave simulations. In addition, the effects of loss and parameter perturbations on the performances of the device are also investigated. These results can be used in field of antenna protection and other electromagnetic field engineering.
160.1190 Anisotropic optical materials 160.3918 Metamaterials 260.2710 Inhomogeneous optical media Chinese Optics Letters
2012, 10(7): 071605
Author Affiliations
Abstract
The optical properties of disperse red 1 (DR1) dye molecules can be changed by controlling the molecular configurations using AlPO4-5 (AFI) and SAPO-47 (CHA) single crystals. Polarized and temperature dependent absorption spectra show that DR1 molecules exist as cis configuration in the cages of CHA crystals. The absorption band for cis-configuration is centered at 432 nm, which does not depend on polarization angle and temperature. However, DR1 molecules are well aligned in the channels of AFI crystal with trans configuration. Its absorption band is centered at 520 nm, which shows strongly anisotropic polarizability and shifts to long wavelength with increasing temperature. It can be used as polarizer and temperature sensor. The second harmonic generation (SHG) and photoluminescence (PL) investigations show that the DR1 trans isomers in AFI matrix have potential applications in nonlinear optics.
160.1190 Anisotropic optical materials 160.4236 Nanomaterials 220.4241 Nanostructure fabrication 300.1030 Absorption Chinese Optics Letters
2012, 10(s1): S11601
