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Title: Frequency stabilization via the mixed mode in three mode HeNe lasers

Conference ·
OSTI ID:991817

This paper describes a three mode HeNe laser frequency stabilization technique using the mixed mode frequency to obtain a fractional frequency stability of 2 x 10{sup -11}. The mixed mode frequency occurs due to optical nonlinear interactions with the adjacent modes at each of the three modes. In precision displacement interferometry systems, the laser source frequency must be stabilized to provide an accurate conversion ratio between phase change and displacement. In systems, such as lithography applications, which require high speed, high accuracy and low data age uncertainty, it is also desirable to avoid periodic nonlinearities, which reduces computation time and errors. One method to reduce periodic nonlinearity is to spatially separate the measurement and reference beams to prevent optical mixing, which has been shown for several systems. Using spatially separated beams and the proper optical configuration, the interferometer can be fiber fed, which can increase the interferometer's stability by reducing the number of beam steering optical elements. Additionally, as the number of measurement axes increases, a higher optical power from the laser source is necessary.

Research Organization:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Organization:
USDOE
DOE Contract Number:
W-7405-ENG-48
OSTI ID:
991817
Report Number(s):
LLNL-PROC-423493; TRN: US201021%%390
Resource Relation:
Conference: Presented at: 10th International Conference of the European Society for Precision Engineering and Nanotechnology, Delft, Netherlands, May 31 - Jun 04, 2010
Country of Publication:
United States
Language:
English