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Journal of Biomedical Optics • Open Access

Kinetics of picosecond laser pulse induced charge separation and proton transfer in bacteriorhodopsin
Author(s): Baoli Yao; Dalun Xu; Xun Hou; Kunsheng Hu; Aojin Wang

Paper Abstract

Bacteriorhodopsin (BR) films oriented by an electrophoretic method are deposited on a transparent conductive ITO glass. A counterelectrode of copper and gelose gel is used to compose a sandwich-type photodetector with the structure of ITO/BR film/gelose gel/Cu. A single 30-ps laser pulse and a mode-locked pulse train are respectively used to excite the BR photodetector. The ultrafast falling edge and the bipolar response signal are measured by the digital oscilloscope under seven different time ranges. Marquardt nonlinear least squares fitting is used to fit all the experimental data and a good fitting equation is found to describe the kinetic process of the photoelectric signal. Data fitting resolves six exponential components that can be assigned to a seven-step BR photocycle model: BR→K→KL→L→M→N→O→BR. Comparing tests of the BR photodetector with a 100-ps Si PIN photodiode demonstrates that this type of BR photodetector has at least 100-ps response time and can also serve as a fast photoelectric switch.

Paper Details

Date Published: 1 January 2003
PDF: 5 pages
J. Biomed. Opt. 8(1) doi: 10.1117/1.1527626
Published in: Journal of Biomedical Optics Volume 8, Issue 1
Show Author Affiliations
Baoli Yao, Xi'an Institute of Optics and Precision Mechanics (China)
Dalun Xu, Xi'an Institute of Optics and Precision Mechanics (China)
Xun Hou, Xi'an Institute of Optics and Precision Mechanics (China)
Kunsheng Hu, Institute of Biophysics (China)
Aojin Wang, Institute of Biophysics (China)

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