A shaped annular beam tri-heterodyne confocal microscope with good anti-environmental interference capability
Zhao Wei-Qian(赵维谦)a)† , Feng Zheng-De(冯政德)b), and Qiu Li-Rong(邱丽荣)a)
a School of Information Engineering, Beijing Institute of Technology, Beijing 10081, China; b Department of Automation Measurement and Control Engineering, Harbin Institute of Technology, Harbin 150001, China
Abstract A shaped annular beam tri-heterodyne confocal microscope has been proposed to improve the anti-environmental interference capability and the resolution of a confocal microscope. It simultaneously detects far-, on-, and near-focus signals with given phase differences by dividing the measured light path of the confocal microscope into three sub-paths (signals). Pair-wise real-time heterodyne subtraction of the three signals is used to improve the anti-environmental interference capability, axial resolution, and linearity; and a shaped annular beam super-resolution technique is used to improve lateral resolution. Theoretical analyses and preliminary experiments indicate that an axial resolution of about 1 nm can be achieved with a shaped annular beam tri-heterodyne confocal microscope and its lateral resolution can be better than 0.2 $\mu $m for $\lambda =632.8$~nm, the numerical aperture of the lens of the microscope is NA $=0.85$, and the normalized radius $\varepsilon =0.5$.
Received: 12 September 2006
Revised: 27 December 2006
Accepted manuscript online:
PACS:
42.79.Sz
(Optical communication systems, multiplexers, and demultiplexers?)
Fund: Project
supported by the National Natural Science Foundation of China (Grant No
50475035), the Doctoral Program of Higher Education of China
(Grant No~20050213035) and the Program for New Century Excellent Talents in
University of China (Grant No~NCET-05-0348).
Cite this article:
Zhao Wei-Qian(赵维谦), Feng Zheng-De(冯政德), and Qiu Li-Rong(邱丽荣) A shaped annular beam tri-heterodyne confocal microscope with good anti-environmental interference capability 2007 Chinese Physics 16 1624
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