Tsinghua University

Shulian Zhang

Yan Li

Jun Zhu

Sen Yang

Kuofam Jin

Yingchun Ding

Minxian Wu

A frequency splitting laser micrometer for measuring a displacement of an object. The laser micrometer includes a frequency splitting laser directing a first frequency splitting laser beam to the object via a laser output mirror at one end of the laser. The first laser beam is reflected thus outputting a second frequency splitting laser beam, such that a feedback cavity is created, wherein a frequency of the second laser beam is decided by a cavity length of said feedback cavity and accordingly the displacement of the object. A detecting and signal processing unit receives said first and second frequency splitting laser beams and measures the displacement of the object according to interference effects of said first and second laser beams.

Frequency splitting laser micrometer

A birefringent quartz plate is inserted in the laser cavity to generate two orthogonal polarized beams with different frequencies, and with the amount of frequency difference depending upon the angle of orientation of the crystalline axis of the quartz plate with respect to the longitudinal axis of the laser beam in the cavity. Frequency differences between the generated dual frequency beams can be varied from tens of MHz to more than 1000 MHz, with tuning or variation being effected by a mechanism for rotating the quartz plate. This apparatus provides a dual-frequency laser for interferometry, laser Doppler velocimeters and other applications.

Quartz crystal tuning he-ne double frequency laser

Growing community of inventors

Beijing, China

Shulian Zhang