Rapid Optical Switching by Means of Photoinduced Change in Refractive Index of Azobenzene Liquid Crystals Detected by Reflection-Mode Analysis

1997 ◽  
Vol 119 (33) ◽  
pp. 7791-7796 ◽  
Author(s):  
Atsushi Shishido ◽  
Osamu Tsutsumi ◽  
Akihiko Kanazawa ◽  
Takeshi Shiono ◽  
Tomiki Ikeda ◽  
...  
Keyword(s):  
Refractive Index ◽  
Liquid Crystals ◽  
Optical Switching ◽  
Mode Analysis ◽  
Photoinduced Change ◽  
Reflection Mode

ChemInform Abstract: Distinct Photochemical Phase Transition Behavior of Azobenzene Liquid Crystals Evaluated by Reflection-Mode Analysis.

ChemInform ◽  
2010 ◽  
Vol 28 (28) ◽  
pp. no-no
Author(s):  
A. SHISHIDO ◽  
O. TSUTSUMI ◽  
A. KANAZAWA ◽  
T. SHIONO ◽  
T. IKEDA ◽  
...  
Keyword(s):  
Phase Transition ◽  
Liquid Crystals ◽  
Mode Analysis ◽  
Phase Transition Behavior ◽  
Reflection Mode ◽  
Transition Behavior

Liquid Crystal Photonics: Optical Switching and Image Storage by Means of Azobenzene Liquid-Crystal Films

1996 ◽  
Vol 425 ◽  
Author(s):  
A. Shishido ◽  
O. Tsutsumi ◽  
T. Ikeda
Keyword(s):  
Phase Transition ◽  
Liquid Crystal ◽  
Optical Switching ◽  
Transmission Mode ◽  
Mode Analysis ◽  
Reflection Mode ◽  
Image Storage ◽  
Liquid Crystal Films ◽  
Crystal Films ◽  
One Year

AbstractOptical switching and image storage were explored by means of azobenzene liquid crystals (LCs). Azobenzene derivatives with monomeric and polymeric forms were prepared, which show nematic LC phase in the trans form while no LC phase in the cis form. On pulse irradiation at 355 nm, which causes trans-cis isomerization of the azobenzene moiety, these azobenzene LC films underwent nematic (N) to isotropic (1) phase transition in 100 ˜ 200 μs as probed by change in transmittance of a He-Ne laser through crossed polarizers (transmission-mode analysis) or change in reflectivity at the interface between the sample and glass substrate (reflection-mode analysis). In the reflection-mode analysis, the decay was faster than that observed in the transmission-mode analysis. The N phase recovered through the cis-trans thermal backisomerization process in the transmission-mode analysis, while it was restored through diffusion of the cis form, followed by reorientation of the trans form which replaced the cis form in the interface region, in the reflection-mode analysis. The photochemical N-I phase transition was also induced in 200 μs below Tg of the polymer azobenzene LC. Image could be stored into the polymer azobenzene LC film on photoirradiation to bring about the N-I phase transition and the stored image remained unchanged even after one year when it was kept below Tg of the polymer.

Enhancement of stability in optical switching of photosensitive liquid crystal by means of reflection mode analysis

1999 ◽  
Vol 9 (9) ◽  
pp. 2211-2213 ◽  
Author(s):  
Atsushi Shishido ◽  
Akihiko Kanazawa ◽  
Takeshi Shiono ◽  
Tomiki Ikeda ◽  
Naoto Tamai
Keyword(s):  
Liquid Crystal ◽  
Optical Switching ◽  
Mode Analysis ◽  
Reflection Mode

Distinct Photochemical Phase Transition Behavior of Azobenzene Liquid Crystals Evaluated by Reflection-Mode Analysis

1997 ◽  
Vol 101 (15) ◽  
pp. 2806-2810 ◽  
Author(s):  
Atsushi Shishido ◽  
Osamu Tsutsumi ◽  
Akihiko Kanazawa ◽  
Takeshi Shiono ◽  
Tomiki Ikeda ◽  
...  
Keyword(s):  
Phase Transition ◽  
Liquid Crystals ◽  
Mode Analysis ◽  
Phase Transition Behavior ◽  
Reflection Mode ◽  
Transition Behavior

Azobenzene liquid crystals for fast reversible optical switching and enhanced sensitivity for visible wavelengths

2009 ◽  
Author(s):  
Uladzimir Hrozhyk ◽  
Svetlana Serak ◽  
Nelson Tabiryan ◽  
Diane M. Steeves ◽  
Landa Hoke ◽  
...  
Keyword(s):  
Liquid Crystals ◽  
Optical Switching ◽  
Enhanced Sensitivity ◽  
Visible Wavelengths

SIZE-DEPENDENT NONRESONANT THIRD-ORDER NONLINEAR SUSCEPTIBILITIES OF CdS CLUSTERS FROM 7 TO 120 Å

1992 ◽  
Vol 01 (04) ◽  
pp. 683-698 ◽  
Author(s):  
YING WANG ◽  
NORMAN HERRON
Keyword(s):  
Refractive Index ◽  
Quantum Confinement ◽  
Optical Switching ◽  
Quantum Confinement Effect ◽  
Surrounding Medium ◽  
Confinement Effect ◽  
Third Order ◽  
Size Dependent ◽  
Size Regime ◽  
Fundamental Wavelength

We report the third-order nonlinear susceptibilities χ(3) of CdS clusters (quantum dots) from 7 to 120 Å, measured by third-harmonic generation technique at a fundamental wavelength of 1.91 µm. In the size regime studied, the value of χ(3) first increases with cluster size and then levels off for cluster diameter larger than 60 Å. The volume normalized χ(3) of CdS cluster is about a factor of 2 higher than that of the bulk. These data can be explained by the enhancement in electric field inside the clusters due to the dielectric confinement effect. The size and wavelength dependences of this local field effect have been calculated for CdS clusters. Several trends in the nonresonant χ(3) can be identified: (i) In the absence of quantum confinement effect, the magnitude of χ(3) should be constant in the < 200 Å size regime. It then increases with increasing particle size until the structural resonance regime is reached. (ii) The magnitude of χ(3) can be enhanced by either lowering the refractive index of the surrounding medium or raising the refractive index of the semiconductors. (iii) Quantum confinement, which shifts the band gap to the blue and lowers the refractive index of the semiconductor clusters, reduces the nonresonant χ(3). This is in direct contrast to the resonant nonlinearity which is enhanced by the quantum-confinement effect. Finally, we discuss the size-dependent figure-of-merit of CdS composites for all-optical switching.

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.

scholarly journals Fused ring effect on optical nonlinearity and structure property relationship of anthracenyl chalcone based push-pull chromophores

PLoS ONE ◽  
2021 ◽  
Vol 16 (9) ◽  
pp. e0257808
Author(s):  
Dian Alwani Zainuri ◽  
Mundzir Abdullah ◽  
Muhamad Fikri Zaini ◽  
Hazri Bakhtiar ◽  
Suhana Arshad ◽  
...  
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Electrostatic Potential ◽  
Nonlinear Refractive Index ◽  
Optical Switching ◽  
Nonlinear Optical ◽  
Continuous Wave ◽  
Excited State Absorption ◽  
Nonlinear Optical Properties ◽  
Closed Aperture

The Ultraviolet-visible (UV-Vis) spectra indicate that anthracenyl chalcones (ACs) have high maximum wavelengths and good transparency windows for optical applications and are suitable for optoelectronic applications owing to their HOMO–LUMO energy gaps (2.93 and 2.76 eV). Different donor substituents on the AC affect their dipole moments and nonlinear optical (NLO) responses. The positive, negative, and neutral electrostatic potential regions of the molecules were identified using molecular electrostatic potential (MEP). The stability of the molecule on account of hyperconjugative interactions and accompanying charge delocalization was analyzed using natural bond orbital (NBO) analysis. Open and closed aperture Z-scans were performed using a continuous-wave frequency-doubled diode-pumped solid-state (DPSS) laser to measure the nonlinear absorption and nonlinear refractive index coefficients, respectively. The valley-to-peak profile of AC indicated a negative nonlinear refractive index coefficient. The obtained single crystals possess reverse saturation absorption due to excited-state absorption. The structural and nonlinear optical properties of the molecules have been discussed, along with the role of anthracene substitution for enhancing the nonlinear optical properties. The calculated third-order susceptibility value was 1.10 x10-4 esu at an intensity of 4.1 kW/cm2, higher than the reported values for related chalcone derivatives. The NLO response for both ACs offers excellent potential in optical switching and limiting applications.

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