Temperature-controlled autocollimator with ultrahigh angular measuring precision
- Department of Optoelectronic Engineering, College of Optoelectronic Science and Engineering, National University of Defense Technology, Changsha 410073 (China)
A temperature-controlled autocollimator with ultrahigh angular measuring precision is proposed in this article, which is different from our previous publication [J. Yuan and X. W. Long, Rev. Sci. Instrum. 74, 1362 (2003)]. The autocollimator consists of a zoom lens illuminating a charge-coupled device (CCD). This design provides a compact size and increased stability without compromising precision. Moreover, this design makes it possible to detect a target mirror with either plane reflectors or spherical reflectors. Devices for shock absorption and heat insulation were implemented to diminish external interferences. A special temperature-control system for the autocollimator is designed to control the temperature of the autocollimator. The temperature of the autocollimator fluctuates less than {+-}0.01 deg. C. The CCD camera's noise is a fatal obstacle that prevents us from achieving an ultrahigh angular measuring precision. In this article, the influence of the CCD camera's noise on the measuring resolution is analyzed theoretically in detail. Based on the analysis, some special noise-suppressing methods to eliminate the influence of the CCD camera's noise are proposed. Both the influence of the CCD camera's noise and the noise-suppressing methods have not been discussed in our previous publication [J. Yuan and X. W. Long, Rev. Sci. Instrum. 74, 1362 (2003)]. By using the methods mentioned above, the measuring precision of the autocollimator has been greatly improved and the requirements on the external condition have been greatly reduced. The method is proved to be reliable by a prototype experiment. Two-axis angular displacement can be measured simultaneously and a measuring precision of 0.005 arcsec has been achieved, which is currently the highest measuring precision in the world.
- OSTI ID:
- 20778491
- Journal Information:
- Review of Scientific Instruments, Vol. 76, Issue 12; Other Information: DOI: 10.1063/1.2149010; (c) 2005 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0034-6748
- Country of Publication:
- United States
- Language:
- English
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