Study Of Thz-wave Generation Via Optical Parametric Oscillation And Maximum Atomic Coherence

The range of the terahertz wave (THz-wave) frequency is 0.1~10 THz (the corresponding range of wavelength is 30μm~3mm). THz-wave which locates between the milimeter wave and infrared wave has many special properties such as low energy per photon. The terahertz technique is not only used in basic subject as physics, chemistry and biology, but also used in imaging technique, satellite communications and atmospheric remote sensing, safety inspection, environmental monitoring and so on. The key of the development of the THz technique is the THz source with high performance. The THz radiation source via optical parametric oscillation technique which can produce high power, tunable coherent THz wave has obvious advantages of compactness, simplicity for tuning, operation at room temperature and so on. The THz radiation source via maximum atomic coherence is indicated in recent years because this technique can enhance the process of frequency transformation through the quantum interference. This is such a special superiority that the study on the THz wave radiation via the maximal atomic coherence is very important.The main contents and creation points of this dissertation are as follows:1. We perform detailed simulations of the scattering process of stimulated polariton.2. We study on the theory and the experiment of TPO. We learn the principle of the optical parametric oscillation and the properties of the nonlinear crystal (LiNbO3) of the TPO. Then we obtain the properties of THz-wave gain, absorption and the tunability of TPO. The creation point here is the change of the cavity structure where we put two crystals with a special angle which can enhance the coupling out of the THz-wave.3. Theoretical research about the THz-wave generation via maximum atomic coherence. We perform the detailed stimulations of this scheme in ruby crystal.