Improving Frequency Stability Of Laser By Means Of Temperature-controlled F-P Cavity

The frequency-stability of an al]-solid-state Nd:YVO4 laser is significantly improved by means of a specially designed F-P interferometer used for the frequency standard in the frequency-stabilizing system. In the modem experimental investigation of quantum optics and quantum information, the accuracy of the long-term frequency stability of lasers is required in the range of a few MHz.The temperature of the F-P cavity is accurately controlled by a set of thermoelectric cooler(TEC) modules attached on the body of the cavity and the electronic feed-back circuit. We found that the long-term unidirectional frequency shift of the output laser resulting from the slow increase of the cavity length under the effect of the temperature integration on the cavity body is essentially eliminated. The frequency-stability of the output laser with the power of 530mw is better than ± 200kHz(kilohertz) in 1 minute and ± 2.3MHz(mega-hertz) in 40 minutes respectively, and the fluctuation of output power is smaller than ±0.5% over one hour. By means of controlling accurately temperature of F-P cavity used in the frequency-stabilizing system of laser, the frequency stability of laser is significantly improved. Especially the long-term unidirectional frequency shift is essentially overcome.