The Optical Parametric Process In Sheet Optical Parametric Oscillator

In recent years,optical microcavities are of great interests in the fields such as gas sensing,precision measurement,optical sensing and optical communication.They are compact and easy to integrate.In 1962,Bloembergen et al.proposed the theory that the phase mismatch caused in the nonlinear optical process can be compensated by the microcavity with cavity length of hundreds of micrometers.The concept is the so called Cavity Phase Matching(CPM).Zhenda Xie et al.first realized CPM experimentally in 2011 which demonstrated new optical characteristics and advantages.In this thesis,we develop a series of different Sheet Optical Parametric Oscillator(SOPO)and study the corresponding optical parametric process.Also,we apply the SOPO to the generation of terahertz wave.The main results are listed as follows:1.Firstly,we introduce the development of nonlinear optics and cavity phase matching.The principle of cavity phase matching is briefly elaborated.Then the principle of designing sheet optical parametric oscillator is demonstrated.2.We theorectically analyse the optical parametric chacracteristics of SOPO by introducing the three-coupled-wave equation of the optical parametric process in SOPO.Also,a comparison between the optical features of single pass SOPO and double pass SOPO is made.3.We measured the Sellmeier equation of periodically poled MgO-doped lithium niobate(PPMgOLN)by quasi-phase matched optical parametric oscillator(OPO).The derived Sellmeier equation is valid in the spectral range of 0.5-4?m and the temperature range of 60-510?.This work provides accurate guidance of phase matching for SOPO consists of MgO-doped lithium niobate(MgO:CLN).4.We develop a SOPO using type I CPM based on MgO:CLN.Near the degenerate point at 1064nm,tunable frequency comb spectrum is obtained with bandwidth of 50nm.The conversion efficiency is 33.8%.Also we realize high performance cavity phase matching by pump reflection.5.We develop a double pass SOPO by type II CPM base on KTP crystal.In the spectal range of 1020nm-1120nm,tunable parametric output with single longitude mode and narrow linewidth is obtained.By reflecting the pump light on the output surface,the oscillation threshold is decreased to 21 ?J.The conversion efficiency is 41.05%and slope efficiency is 48.56%.6.We study the application of SOPO in the generation of THz wave.we discuss the generation of THz in GaSe crystal through the difference frequency generation(DFG).Here the double pass SOPO based on KTP is used as the pump source for DFG.The designed THz source based on SOPO is very compact and widely tunable.The calculated tuning range is 0.5THz-25.6THz.The theorectical conversion efficiency is 3.0 ×10-5.