Dynamics of nematic MBBA film induced by transient grating under a strong absorption condition

Bohyun Yoon, Sun Hee Kim, Ilkeun Lee, Seong Kyu Kim, Minhaeng Cho, Hackjin Kim

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

We report time profiles of transient grating diffraction signals created by crossed beam excitation of 170 μm thick nematic MBBA film. At the excitation wavelength of 355 nm and the irradiance of 10 mJ/cm2, corresponding to a strong absorption condition, the signal consists of four distinguishable components in the time range of submicroseconds to milliseconds. When the grating spacing is 8 μm, the fastest component due to thermal diffusion near the surface rises within the time resolution of the experiments (∼20 ns) and decays in about 10 μs. This component exhibits a strong dependence on the polarization of the probe beam, which reduces as the temperature approaches the nematic-isotropic phase transition point. The weakest and slowest component observed in the time scale of 100 ms is identified as mass diffusion of cis-MBBA. The other two components of the diffraction signal dominant in the submillisecond and the millisecond regimes, respectively, display an exponential rise followed by an exponential decay. These components are interpreted as dynamics of the reordering processes induced by temperature perturbation and by the phototransformed state, respectively. As the temperature approaches the phase transition point, the optical nonlinearity increases to such an extent that multiple order diffractions are visible. The phototransformed state, with a significant contribution from laser-induced melting, is the major cause of the extraordinarily high optical nonlinearlity of MBBA near the phase transition point.

Original languageEnglish
Pages (from-to)7705-7713
Number of pages9
JournalJournal of Physical Chemistry B
Volume102
Issue number40
Publication statusPublished - 1998 Oct 1

Fingerprint

Phase transitions
gratings
transition points
Diffraction
Thermal diffusion
Diffraction gratings
Temperature
Melting
Polarization
Wavelength
Lasers
decay
thermal diffusion
gratings (spectra)
diffraction
irradiance
excitation
temperature
Experiments
nonlinearity

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Engineering(all)

Cite this

Dynamics of nematic MBBA film induced by transient grating under a strong absorption condition. / Yoon, Bohyun; Kim, Sun Hee; Lee, Ilkeun; Kim, Seong Kyu; Cho, Minhaeng; Kim, Hackjin.

In: Journal of Physical Chemistry B, Vol. 102, No. 40, 01.10.1998, p. 7705-7713.

Research output: Contribution to journalArticle

Yoon, Bohyun ; Kim, Sun Hee ; Lee, Ilkeun ; Kim, Seong Kyu ; Cho, Minhaeng ; Kim, Hackjin. / Dynamics of nematic MBBA film induced by transient grating under a strong absorption condition. In: Journal of Physical Chemistry B. 1998 ; Vol. 102, No. 40. pp. 7705-7713.
@article{6c3589986b1b4aea9cc4887f110855e4,
title = "Dynamics of nematic MBBA film induced by transient grating under a strong absorption condition",
abstract = "We report time profiles of transient grating diffraction signals created by crossed beam excitation of 170 μm thick nematic MBBA film. At the excitation wavelength of 355 nm and the irradiance of 10 mJ/cm2, corresponding to a strong absorption condition, the signal consists of four distinguishable components in the time range of submicroseconds to milliseconds. When the grating spacing is 8 μm, the fastest component due to thermal diffusion near the surface rises within the time resolution of the experiments (∼20 ns) and decays in about 10 μs. This component exhibits a strong dependence on the polarization of the probe beam, which reduces as the temperature approaches the nematic-isotropic phase transition point. The weakest and slowest component observed in the time scale of 100 ms is identified as mass diffusion of cis-MBBA. The other two components of the diffraction signal dominant in the submillisecond and the millisecond regimes, respectively, display an exponential rise followed by an exponential decay. These components are interpreted as dynamics of the reordering processes induced by temperature perturbation and by the phototransformed state, respectively. As the temperature approaches the phase transition point, the optical nonlinearity increases to such an extent that multiple order diffractions are visible. The phototransformed state, with a significant contribution from laser-induced melting, is the major cause of the extraordinarily high optical nonlinearlity of MBBA near the phase transition point.",
author = "Bohyun Yoon and Kim, {Sun Hee} and Ilkeun Lee and Kim, {Seong Kyu} and Minhaeng Cho and Hackjin Kim",
year = "1998",
month = "10",
day = "1",
language = "English",
volume = "102",
pages = "7705--7713",
journal = "Journal of Physical Chemistry B Materials",
issn = "1520-6106",
publisher = "American Chemical Society",
number = "40",

}

TY - JOUR

T1 - Dynamics of nematic MBBA film induced by transient grating under a strong absorption condition

AU - Yoon, Bohyun

AU - Kim, Sun Hee

AU - Lee, Ilkeun

AU - Kim, Seong Kyu

AU - Cho, Minhaeng

AU - Kim, Hackjin

PY - 1998/10/1

Y1 - 1998/10/1

N2 - We report time profiles of transient grating diffraction signals created by crossed beam excitation of 170 μm thick nematic MBBA film. At the excitation wavelength of 355 nm and the irradiance of 10 mJ/cm2, corresponding to a strong absorption condition, the signal consists of four distinguishable components in the time range of submicroseconds to milliseconds. When the grating spacing is 8 μm, the fastest component due to thermal diffusion near the surface rises within the time resolution of the experiments (∼20 ns) and decays in about 10 μs. This component exhibits a strong dependence on the polarization of the probe beam, which reduces as the temperature approaches the nematic-isotropic phase transition point. The weakest and slowest component observed in the time scale of 100 ms is identified as mass diffusion of cis-MBBA. The other two components of the diffraction signal dominant in the submillisecond and the millisecond regimes, respectively, display an exponential rise followed by an exponential decay. These components are interpreted as dynamics of the reordering processes induced by temperature perturbation and by the phototransformed state, respectively. As the temperature approaches the phase transition point, the optical nonlinearity increases to such an extent that multiple order diffractions are visible. The phototransformed state, with a significant contribution from laser-induced melting, is the major cause of the extraordinarily high optical nonlinearlity of MBBA near the phase transition point.

AB - We report time profiles of transient grating diffraction signals created by crossed beam excitation of 170 μm thick nematic MBBA film. At the excitation wavelength of 355 nm and the irradiance of 10 mJ/cm2, corresponding to a strong absorption condition, the signal consists of four distinguishable components in the time range of submicroseconds to milliseconds. When the grating spacing is 8 μm, the fastest component due to thermal diffusion near the surface rises within the time resolution of the experiments (∼20 ns) and decays in about 10 μs. This component exhibits a strong dependence on the polarization of the probe beam, which reduces as the temperature approaches the nematic-isotropic phase transition point. The weakest and slowest component observed in the time scale of 100 ms is identified as mass diffusion of cis-MBBA. The other two components of the diffraction signal dominant in the submillisecond and the millisecond regimes, respectively, display an exponential rise followed by an exponential decay. These components are interpreted as dynamics of the reordering processes induced by temperature perturbation and by the phototransformed state, respectively. As the temperature approaches the phase transition point, the optical nonlinearity increases to such an extent that multiple order diffractions are visible. The phototransformed state, with a significant contribution from laser-induced melting, is the major cause of the extraordinarily high optical nonlinearlity of MBBA near the phase transition point.

UR - http://www.scopus.com/inward/record.url?scp=0032188639&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0032188639&partnerID=8YFLogxK

M3 - Article

AN - SCOPUS:0032188639

VL - 102

SP - 7705

EP - 7713

JO - Journal of Physical Chemistry B Materials

JF - Journal of Physical Chemistry B Materials

SN - 1520-6106

IS - 40

ER -