PHOTOMECHANICAL ACTUATOR DEVICE BASED ON DISPERSE RED 1 DOPED POLY ...

168 Pages·2013·11.44 MB·English

PHOTOMECHANICAL ACTUATOR DEVICE BASED ON DISPERSE RED 1
DOPED POLY(METHYL METHACRYLATE) OPTICAL FIBER
By
XIANJUN YE
A dissertation submitted in partial fulfillment of
the requirements for the degree of
Doctor of Philosophy
WASHINGTON STATE UNIVERSITY
Department of Physics and Astronomy
DECEMBER 2013
c Copyright by XIANJUN YE, 2013
(cid:13)
All Rights Reserved
c Copyright by XIANJUN YE, 2013
(cid:13)
All Rights Reserved
To the Faculty of Washington State University:
The members of the Committee appointed to examine the dissertation of XIAN-
JUN YE find it satisfactory and recommend that it be accepted.
Mark G. Kuzyk, Ph.D., Chair
Matthew D. McCluskey, Ph.D.
Peter W. Engels, Ph.D.
Yi Gu, Ph.D.
ii
ACKNOWLEDGMENTS
First andforemost, Iwould like tothank my supervisor Professor Mark G. Kuzyk, the
wizard of light, for giving me the opportunity to enrich myself between fascinating
optical research topics, from optical tweezers to photomechanics, and for his vast
knowledge on optics and other aspects of life which has been a great inspiration to
me.
I would like to thank my research committee: Professors Matthew D. McCluskey
for generously allowing me to use the PVD apparatus, Peter W. Engels for his will-
ingness to listen and help, Yi Gu for providing me access to the testing instruments
and software in the Electronics Lab. I thank Professor John B. Schneider at EECS of
WSU, for his numerical computation class providing me the necessary programming
skill to tackle my research problems.
I also want to thank my present and past office mates, Mr. Shengting Hung,
Dr. Nathan Dawson, and Dr. Shiva K. Ramini, for sharing stories and jokes when
research was tossed aside. I thank all the members of the group for making the
nonlinear optics lab a wonderful working place, and all other people who have offered
help during my stay at WSU.
I thank Department of Physics and National Science Foundation for their gen-
erous funding support in various forms such as Teaching assistantship, Millennium
fellowship, and research grants.
Last, I’d like to thank my family for their great patience and endless support
during these years.
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PHOTOMECHANICAL ACTUATOR DEVICE BASED ON DISPERSE RED 1
DOPED POLY(METHYL METHACRYLATE) OPTICAL FIBER
Abstract
by Xianjun Ye, Ph.D.
Washington State University
December 2013
Chair: Mark G. Kuzyk
The photomechanical effect is the phenomenon involving any mechanical property
change of a material induced by light exposure. Photomechanical devices can be
built with superior performance over traditional devices and offer versatile control
tactics.
Previousexperimentsshowthatdispersered1azobenzene(DR1)dopedpoly(methyl
methacrylate) (PMMA) optical fiber hasa fastphotomechanical response uponasym-
metrical 633nm laser irradiation originating in photoisomerization of the dopants be-
tween the cis and trans forms, which causes an elongation of the polymer fiber. In
this work, laser light of 355nm wavelength is used to investigate the dynamics of the
trans to cis photoisomerization process, which should result in length contraction of
the DR1dopedPMMA polymer fiber. Athree-point-contact optically-actuated beam
controlling tilt mount is made and used as the measurement apparatus to study this
process. The photomechanical fiber is observed to elongate upon UV irradiation.
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Numerical simulations, which take into account the coupled effect between the
laser-inducedtemperatureincreaseandpopulationdensitychangeofthedyemolecules,
show that contraction of the fiber due to direct trans-cis photoisomerization is over-
whelmed by elongation due to the photo-thermally-stimulated cis-trans isomerization
under high intensity. An ink coated entrance face of the fiber is placed in the mea-
surement tilt mount and is found to exhibit contraction in the fast process under
low intensity without sacrificing the good signal to noise ratio enjoyed in the high
intensity case.
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DEDICATION
To My Parents
Huaqing Ye and Lianzhi Cheng
vi
Contents
Table of Contents vii
List of Figures x
List of Tables xvi
1 Introduction 1
1.1 Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 Previous Work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.3 Mechanisms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.3.1 Photothermal Heating . . . . . . . . . . . . . . . . . . . . . . 4
1.3.2 Photostriction . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.3.3 Photoreorientation . . . . . . . . . . . . . . . . . . . . . . . . 5
1.3.4 Photoisomerization . . . . . . . . . . . . . . . . . . . . . . . . 7
1.3.5 Photomechnics in Human Eye . . . . . . . . . . . . . . . . . . 9
2 Device Fabrication 11
2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.2 Polymer Fiber Drawing . . . . . . . . . . . . . . . . . . . . . . . . . . 12
2.3 Physical Vapor Deposition . . . . . . . . . . . . . . . . . . . . . . . . 15
2.3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
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2.3.2 Pumping Stage . . . . . . . . . . . . . . . . . . . . . . . . . . 17
2.3.3 Boostivac System . . . . . . . . . . . . . . . . . . . . . . . . . 17
2.3.4 Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
2.4 Device Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
2.4.1 Polish and Cut Fiber . . . . . . . . . . . . . . . . . . . . . . . 22
2.4.2 Photomechanical Fabry-Perot Interferometer . . . . . . . . . . 24
2.4.3 Photomechanical Tilt Mount with C Leg . . . . . . . . . . . . 26
3 Experiment 29
3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
3.2 Graphical Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
3.3 Main Experiment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
3.3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
3.3.2 Calibration of Quadrant Photodetector . . . . . . . . . . . . . 34
3.3.3 Experimental Setup . . . . . . . . . . . . . . . . . . . . . . . . 35
3.3.4 Vibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
3.4 Supplemental Experiment . . . . . . . . . . . . . . . . . . . . . . . . 41
4 Results and Discussions 43
4.1 Experimental Results . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
4.2 Photoreorientation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
4.3 Photoisomerization . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
4.4 Mechanical Constraints . . . . . . . . . . . . . . . . . . . . . . . . . . 64
4.4.1 Equations of Motion . . . . . . . . . . . . . . . . . . . . . . . 65
4.4.2 Empirical Solution . . . . . . . . . . . . . . . . . . . . . . . . 69
4.4.3 Alternative Approach . . . . . . . . . . . . . . . . . . . . . . . 71
4.5 Photothermal Heating . . . . . . . . . . . . . . . . . . . . . . . . . . 71
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5 Numerical Analysis 75
5.1 Thermal Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
5.1.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
5.1.2 Fourier’s Law of Heat Conduction . . . . . . . . . . . . . . . . 75
5.1.3 Heat Conduction in 1D with no Heat Source . . . . . . . . . . 78
5.1.4 Heat Conduction in 1D with Transient Heat Source . . . . . . 80
5.1.5 Heat Conduction in 1D with Continuous Heat Source . . . . . 82
5.2 Modeling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
5.3 Numerical Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
5.3.1 High Pump Intensity . . . . . . . . . . . . . . . . . . . . . . . 91
5.3.2 Low Pump Intensity . . . . . . . . . . . . . . . . . . . . . . . 93
5.3.3 Results and Discussions . . . . . . . . . . . . . . . . . . . . . 96
5.3.4 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
6 Conclusions 99
Appendix A Samples 101
Appendix B Quadrant Photodiode 103
Appendix C LABVIEW Data Acquisition 107
C.1 Signal Conditioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
C.2 VI for LabJack U3-LV . . . . . . . . . . . . . . . . . . . . . . . . . . 110
C.3 VI for LeCroy Oscilloscopes . . . . . . . . . . . . . . . . . . . . . . . 114
Appendix D Computer Scripts 119
D.1 Complete C Code for Numerical Simulation . . . . . . . . . . . . . . 119
D.2 MATLAB Code for Data Plot . . . . . . . . . . . . . . . . . . . . . . 132
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