The refractive index dispersion and the optical constants of liquid crystal metal-free and nickel(II) phthalocyanines

2006 ◽  
Vol 373 (2) ◽  
pp. 262-266 ◽  
Author(s):  
F. Yakuphanoglu ◽  
M. Durmuş ◽  
M. Okutan ◽  
O. Köysal ◽  
V. Ahsen
Keyword(s):  
Refractive Index ◽  
Liquid Crystal ◽  
Optical Constants ◽  
Refractive Index Dispersion ◽  
Metal Free

Optically induced birefringence in dye-doped blue phase liquid crystals

2019 ◽  
Vol 46 (6) ◽  
pp. 913-919
Author(s):  
Lin ◽  
Kuo ◽  
Huang ◽  
Wu ◽  
Lin ◽  
...  
Keyword(s):  
Refractive Index ◽  
Liquid Crystal ◽  
Pump Beam ◽  
Pump Intensity ◽  
Photoinduced Change ◽  
Methyl Red ◽  
Sem Images ◽  
Photoinduced Birefringence ◽  
Phase Liquid ◽  
Blue Phase

This paper investigates the photoinduced change of refractive index in dye (methyl red, MR)-doped blue phase (DDBP) cells by illumination of a pump beam. Through excitation of light irradiation with proper photon energy, MR can transform from trans-state to cis-state and successively diffuse and anisotropically adsorb on the inner glass substrate of the DDBP cell along the direction perpendicular to the polarisation of the pump beam. The adsorbed MR molecules can effectively rotate the orientation of the liquid crystal (LC) molecules and thereby modulate the effective refractive index of the DDBP cell. The SEM images of the adsorbed regions of the illuminated DDBP samples were also taken for discussing the relation between the pump intensity and the photoinduced birefringence.

Refractive index dispersion and its temperature dependence in GaS

1983 ◽  
Vol 99 (9) ◽  
pp. 437-440 ◽  
Author(s):  
H. Neumann ◽  
M. Lorenz ◽  
W. Hörig ◽  
F. Lévy
Keyword(s):  
Refractive Index ◽  
Temperature Dependence ◽  
Refractive Index Dispersion

Soft X-ray refractive index by reconciling total electron yield with specular reflection: experimental determination of the optical constants of graphite

2018 ◽  
Vol 25 (5) ◽  
pp. 1433-1443
Author(s):  
C. Jansing ◽  
H. Wahab ◽  
H. Timmers ◽  
A. Gaupp ◽  
H.-C. Mertins
Keyword(s):  
Refractive Index ◽  
Optical Constants ◽  
Specular Reflection ◽  
Complex Refractive Index ◽  
Reflection Spectra ◽  
Total Electron Yield ◽  
Total Electron ◽  
X Ray ◽  
Electron Yield ◽  
Saturation Effects

The complex refractive index of many materials is poorly known in the soft X-ray range across absorption edges. This is due to saturation effects that occur there in total-electron-yield and fluorescence-yield spectroscopy and that are strongest at resonance energies. Aiming to obtain reliable optical constants, a procedure that reconciles electron-yield measurements and reflection spectroscopy by correcting these saturation effects is presented. The procedure takes into account the energy- and polarization-dependence of the photon penetration depth as well as the creation efficiency for secondary electrons and their escape length. From corrected electron-yield spectra the absorption constants and the imaginary parts of the refractive index of the material are determined. The real parts of the index are subsequently obtained through a Kramers–Kronig transformation. These preliminary optical constants are refined by simulating reflection spectra and adapting them, so that measured reflection spectra are reproduced best. The efficacy of the new procedure is demonstrated for graphite. The optical constants that have been determined for linearly polarized synchrotron light incident with p- and s-geometry provide a detailed and reliable representation of the complex refractive index of the material near π- and σ-resonances. They are also suitable for allotropes of graphite such as graphene.

scholarly journals Optical constants of sputtered beryllium thin films determined from photoabsorption measurements in the spectral range 20.4–250 eV

2020 ◽  
Vol 27 (1) ◽  
pp. 75-82
Author(s):  
Mikhail Svechnikov ◽  
Nikolay Chkhalo ◽  
Alexey Lopatin ◽  
Roman Pleshkov ◽  
Vladimir Polkovnikov ◽  
...  
Keyword(s):  
Thin Films ◽  
Refractive Index ◽  
Synchrotron Radiation ◽  
Initial Data ◽  
Absorption Coefficient ◽  
Energy Range ◽  
Transmission Coefficient ◽  
Radiation Source ◽  
Optical Constants ◽  
Free Standing

In this work, the refractive index of beryllium in the photon energy range 20.4–250 eV was experimentally determined. The initial data include measurements of the transmittance of two free-standing Be films with thicknesses of 70 nm and 152 nm, as well as reflectometric measurements of similar films on a substrate. Measurements were carried out at the optics beamline of the BESSY II synchrotron radiation source. The absorption coefficient β was found directly from the transmission coefficient of the films, and the real part of the polarizability δ was calculated from the Kramers–Kronig relations. A comparison is carried out with results obtained 20 years ago at the ALS synchrotron using a similar methodology.

Minimal group refractive index dispersion and gain evolution in ultra-broad-band quantum cascade lasers

2002 ◽  
Vol 14 (12) ◽  
pp. 1671-1673 ◽  
Author(s):  
C. Gmachl ◽  
A. Soibel ◽  
R. Colombelli ◽  
D.L. Sivco ◽  
F. Capasso ◽  
...  
Keyword(s):  
Refractive Index ◽  
Quantum Cascade Lasers ◽  
Broad Band ◽  
Refractive Index Dispersion ◽  
Minimal Group ◽  
Quantum Cascade ◽  
Group Refractive Index ◽  
Cascade Lasers

The generalized Morse wavelet method to determine refractive index dispersion of dielectric films

2017 ◽  
Vol 28 (4) ◽  
pp. 045013
Author(s):  
Özlem Kocahan ◽  
Seçkin Özcan ◽  
Emre Coşkun ◽  
Serhat Özder
Keyword(s):  
Refractive Index ◽  
Dielectric Films ◽  
Refractive Index Dispersion ◽  
Wavelet Method
Sign in / Sign up

Export Citation Format

Share Document