Characteristic Analysis of Anti-Reflective Subwavelength Cross Gratings Fabricated With Holographic Technique

Author(s):  
Fengmei Zhao ◽  
Xiangsu Zhang ◽  
Shou Liu ◽  
Xuechang Ren

The paper presents the investigation on anti-reflection property of subwavelength cross-gratings with relief profile close to pyramid or cone. Such gratings are polarization independent and have effective refractive index increasing gradually from the top to the substrate. Theoretical analysis indicates that, to obtain good anti-reflection effect, for normally incident lights in visible band (400 ∼ 700 nm) the grating period should not be larger than 266 nm. Cross gratings with different periods were fabricated using holographic double-exposure method on photoresist. Measurements show that the grating with 255 nm period has higher transmittance compared with the gratings with the periods larger than 266 nm. Measurements also show that larger grating depth results in higher transmittance. The experimental results are in good agreement with the theoretical analysis.

2020 ◽  
pp. 131-138

The nonlinear optical properties of pepper oil are studied by diffraction ring patterns and Z-scan techniques with continuous wave beam from solid state laser at 473 nm wavelength. The nonlinear refractive index of the sample is calculated by both techniques. The sample show high nonlinear refractive index. Based on Fresnel-Kirchhoff diffraction integral, the far-field intensity distributions of ring patterns have been calculated. It is found that the experimental results are in good agreement with the theoretical results. Also the optical limiting property of pepper oil is reported. The results obtained in this study prove that the pepper oil has applications in nonlinear optical devices.


2017 ◽  
Vol 137 (11) ◽  
pp. 415-416 ◽  
Author(s):  
Tomoki Shimizu ◽  
Yoshiaki Kanamori ◽  
Kazuhiro Hane

1996 ◽  
Vol 05 (04) ◽  
pp. 653-670 ◽  
Author(s):  
CÉLINE FIORINI ◽  
JEAN-MICHEL NUNZI ◽  
FABRICE CHARRA ◽  
IFOR D.W. SAMUEL ◽  
JOSEPH ZYSS

An original poling method using purely optical means and based on a dual-frequency interference process is presented. We show that the coherent superposition of two beams at fundamental and second-harmonic frequencies results in a polar field with an irreducible rotational spectrum containing both a vector and an octupolar component. This enables the method to be applied even to molecules without a permanent dipole such as octupolar molecules. After a theoretical analysis of the process, we describe different experiments aiming at light-induced noncentrosymmetry performed respectively on one-dimensional Disperse Red 1 and octupolar Ethyl Violet molecules. Macroscopic octupolar patterning of the induced order is demonstrated in both transient and permanent regimes. Experimental results show good agreement with theory.


1996 ◽  
Vol 118 (3) ◽  
pp. 330-334 ◽  
Author(s):  
S. Qin ◽  
H. M. Shang ◽  
C. L. Giam ◽  
C. E. Tee

When a bar having one end bonded to a rigid support with foam-adhesive is loaded, the high peeling stresses at the bonded edge foster edge delamination along the interface of bonding. Upon inspection by double exposure holography, with an incremental point load applied at the free end of the bar between exposures, the indistinct fringe perturbation and the unknown resilience of the foam-adhesive (quantified by its foundation modulus) impede unambiguous evaluation of the condition of adhesion. This paper describes a simple method for rapid detection and assessment of artificially created edge delamination in such bar structures. The theoretical analysis elucidates the suitability of modelling the bar as partially clamped, and having an equivalent slope at its support related to the foundation modulus. Two dimensionless parameters are defined, which have between them a linear relationship for a nondelaminated bonding but a nonlinear relationship for a delaminated one. Finally, a simple iterative procedure is described for estimating the delaminated length without having to predetermine the elasticity of the support.


2007 ◽  
Vol 21 (30) ◽  
pp. 5075-5089 ◽  
Author(s):  
HALA M. KHALIL ◽  
MOHAMMED M. SHABAT ◽  
SOFYAN A. TAYA ◽  
MAZEN M. ABADLA

In this work, we present an extensive theoretical analysis of nonlinear optical waveguide sensor. The waveguide under consideration consists of a thin dielectrica film surrounded by a self-focused nonlinear cladding and a linear substrate. The nonlinearity of the cladding is considered to be of Kerr-type. Both cases, when the effective refractive index is greater and when it is smaller than the index of the guiding layer, are discussed. The sensitivity of the effective refractive index to any change in the cladding index in evanescent optical waveguide sensor is derived for TM modes. Closed form analytical expressions and normalized charts are given to provide the conditions required for the sensor to exhibit its maximum sensitivity. The results are compared with those of the well-known linear evanescent waveguide sensors.


1989 ◽  
Vol 172 ◽  
Author(s):  
T. S. Aurora ◽  
D. O. Pederson ◽  
S. M. Day

AbstractLinear thermal expansion and refractive index variation have been measured in lead fluoride with a laser interferometer as a function of temperature. Data has been analyzed using the Lorentz-Lorenz relation. Molecular polarizability, band gap, variation of refractive index with density, and strain-polarizability parameter have been studied as a function of temperature. They exhibit a small variation with temperature except near the superionic phase transition where the variation appears to be more pronounced. The results are in good agreement with the published data near room temperature.


2015 ◽  
Vol 8 (6) ◽  
pp. 2625-2638 ◽  
Author(s):  
L. Wu ◽  
O. Hasekamp ◽  
B. van Diedenhoven ◽  
B. Cairns

Abstract. We investigated the importance of spectral range and angular resolution for aerosol retrieval from multiangle photopolarimetric measurements over land. For this purpose, we use an extensive set of simulated measurements for different spectral ranges and angular resolutions and subsets of real measurements of the airborne Research Scanning Polarimeter (RSP) carried out during the PODEX and SEAC4RS campaigns over the continental USA. Aerosol retrievals performed from RSP measurements show good agreement with ground-based AERONET measurements for aerosol optical depth (AOD), single scattering albedo (SSA) and refractive index. Furthermore, we found that inclusion of shortwave infrared bands (1590 and/or 2250 nm) significantly improves the retrieval of AOD, SSA and coarse mode microphysical properties. However, accuracies of the retrieved aerosol properties do not improve significantly when more than five viewing angles are used in the retrieval.


2020 ◽  
Vol 10 (4) ◽  
pp. 375-386 ◽  
Author(s):  
Jiankai Zhu ◽  
Xiangxian Wang ◽  
Yuan Wu ◽  
Yingwen Su ◽  
Tianxu Jia ◽  
...  

Abstract In this paper, we propose two kinds of composite structures based on the one- and two-dimensional (1D&2D) gold grating on a gold film for plasmonic refractive index sensing. The resonance modes and sensing characteristics of the composite structures are numerically simulated by the finite-difference time-domain method. The composite structure of the 1D gold semi-cylinder grating and gold film is analyzed first, and the optimized parameters of the grating period are obtained. The sensitivity and figure of merit (FOM) can reach 660RIU/nm and 169RIU−1, respectively. Then, we replace the 1D grating with the 2D gold semi-sphere particles array and find that the 2D grating composite structure can excite strong surface plasmon resonance intensity in a wider period range. The sensitivity and FOM of the improved composite structure can reach 985RIU/nm and 298 RIU−1, respectively. At last, the comparison results of the sensing performance of the two structures are discussed. The proposed structures can be used for bio-chemical refractive index sensing.


2000 ◽  
Vol 77 (SUPPLEMENT) ◽  
pp. 192
Author(s):  
Arthur Ho ◽  
Paul Erickson ◽  
Therese Pham ◽  
Fabrice Manns ◽  
Jean-Marie Parel

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