Research Of Laser Frequency Stabilization Characteristic By Using PDH Technique

Ultra-stable and narrow-linewidth laser has been widely used in high-precision laser spectroscopy,measurernents of fundamental physics constants,cold atomic system and optical frequency standards.To achieve superior stability,a free-running laser is usually servo-locked to the resonance frequency of an ultra-stable and high finesse optical cavity.By using the PDH technique,we study the principle and characteristics of He-Ne laser frequency stabilization theoretically and experimentally.The principle and the characteristics of the PDH technique are described in this thesis.Then the influence of modulation frequency and modulation index of electro-optical phase modulator on the dispersion spectrum is discussed.We also analyze the influence of finesse,mode matching and stability of the F-P cavity on the optical heterodyne spectrum and frequency stability of laser.Based on the above analysis,we design a proper F-P cavity,which is suitable for He-Ne laser frequency stabilization.Experimentally,we make an electro-optical phase modulator and an F-P cavity, and measure the related parameters of the F-P cavity.We establish the PDH frequency stabilization system to lock the He-Ne laser's frequency to the resonance frequency of the F-P cavity.Then this laser beats with another frequency stabilized He-Ne laser using two longitudinal modes locking technique.The results show that the stability of the He-Ne laser with PDH technique is about 10^-10 lever in 1 s average time and 10^-11 lever in 100 s average time.At last we measure the frequency drift of He-Ne frequency stabilized laser under the influence of temperature fluctuation.