| dc.description.abstract | For frequency stabilization of the gas laser, we studied the first the polarization properties of a short internal-mirror 612 nm He-Ne laser. We found that polarization flip did not occur at the symmetric two-mode location but near the center of the power profile. Therefore, the laser could be frequency-stabilized using the two-mode method, and the stability achieved was better than 5 ×10-10 . This laser can be used as a light source in length measurements using multi-color interferometers. On the other hand, we studied the polarization properties of an internal-mirror 1523 nm He-Ne laser without and with a magnetic field. When the axial magnetic field was around 12 mT, the laser operated in single mode with two opposite circularly polarized components near the center of gain profile. In addition, due to the competition between these two opposite circularly polarized components, each mode had only one circularly polarized component survived when the laser operated in the two-mode region. We could stabilize the laser frequency at either the center of gain profile or the symmetric two-mode taking advantage of the power difference between the two circularly polarized components of the laser output, and the stability achieved was better than 1 MHz.
For frequency stabilization of the solid state laser, we attempted to develop a new method of simple and low cost to stabilize a diode pumped monolithic Nd:YAG laser. First, we measured the birefringence of a Fabry-Perot etalon under applied stress and axial magnetic field. The stress optical coefficient and Verdet constant of fused silica obtain were 1.7×10-12 m2/N and 2.95 rad．Tesla-1．M-1 at wavelength of 1064 nm. For frequency stabilization of our laser, the suitable birefringence of the Fabry-Perot etalon was generated by applying stress of 60 g/cm2 or an axial magnetic field of 20 mT. The frequency stability obtained was 2 kHz. Next, we studied frequency modulation (FM) saturated absorption spectroscopy of 127I2 near 532 nm by using a periodically-poled LiNbO3 single-pass frequency doubler. The hyperfine transition of iodine near 532 nm was observed by a vibrating mirror.
For frequency stabilization of semiconductor laser, we report, for the first time, the observation of the iodine hyperfine transitions at 531 nm using a frequency-doubled angled-grating DFB (α-DFB) semiconductor laser. The moderate high power of the α-DFB laser allows us to generate the second harmonic light by a periodically-poled LiNbO3 single-pass frequency doubler. We can stabilize this laser frequency to the hyperfine component a10 of R(94) 34-0 or R(70) 33-0 I2 line, and the preliminary frequency stability was about 5 × 10-11. This laser system is an attractive frequency standard at 531 nm due to its compact size, high reliability, and low cost. | en_US |