Theoretical And Experimental Studies Of Optical Parametric Chirped Pulse Amplification

This paper summarizes the development and level of ultrashort and ultrahigh intensity pulse laser technique. A rapidly evolving and exciting field in the current development of lasers is the generation of ultrashort pulses and ultrahigh peak powers fostered by the technique of chirped pulse amplification (CPA). The future development of these systems to higher powers would require the generation of shorter pulses. However CPA has already reached its practical limit in pulse duration, as determined by the gain narrowing effect within the amplifier medium. These limitations are largely removed using a novel technique called optical parametric chirped pulse amplification (OPCPA). The basic idea and development of the OPCPA technique has been summarized. A general theory of OPCPA has not been established, therefore its idea and theory would be further developed and perfected.A detailed theoretical study of optical parametric amplification for OPCPA technique was presented. The theoretical derivations reviewed and extended the coupled wave equation analysis for OPCPA. The theoretical treatment includes the transition from parametric amplification solutions without pump depletion to solutions valid where pump depletion is important for OPCPA. A parametric amplifier general solution program with and without time dependence is discussed. The connection between the solutions including pump depletion and derivations assuming nondepleted pump waves was established. Some effects on OPCPA are analysed and discussed, the results show: the group-velocity mismatch can be neglected for OPCPA; higher parametric transformation efficiency can be obtained in OPCPA; the gain spectra and phase spectra have some effects on the output pulse duration.The bandwidth of three-wave mixing optical parametric amplifiers has been investigated. The general mathematical models for evaluating parametric bandwidth and gain bandwidth of three -wave mixing parametric amplifiers are developed via three-wave noncollinear interactions, the models takes into account crystal-length, noncollinear-angle, group-velocity, group-velocity-dispersion and gain-coefficient effects, and detailed numerical simulations, analysis and comparison carried out. TheABSTRACTresults show that the bandwidths are mostly limited by the group-velocity mismatch between the signal and idler, the widest bandwidth can be obtained when the GV between the signal and idler through noncollinear phase-matched technique. Therefore, for any a three-wave mixing parametric amplifier, the widest bandwidth can be obtained by choosing noncollinear angle, crystal-length and pump intensity, the super-broad-bandwidth gain can be realized. These results are important for producing and amplifying very short femoto-second laser pulses to build ultrashort and ultrahigh pulse laser system by OPCPA at present.Phase matching technique for noncollinear optical parametric generation is first investigated. All the possible phase matching configurations and existence conditions for general noncollinear three-wave mixing interactions are derived for propagation within the crystal principal planes. Numerical calculation expressions for the critical phase matching angles are presented wherever possible. Finally, as an application of these expressions, several numerical calculations of the phase matching angles for general noncollinear phase-matched optical parametric amplification in the nonlinear-optical crystals such as p-BaB2O4 (BBO), LiB3O5 (LBO) and KTiOP04 (KTP) are completed, and the results are graphically presented.The characteristic properties of type I(e-"o+o) nocollinear phase-matched LBCKLiBsOs) optical parametric chirped pulse amplifier are investigated. A theoretical model of noncollinear phase-matched parametric process in LBO is presented. Using the numerical method, the analytical formulation for the noncollinear angle, phase-matched angle, walkoff angle, acceptance angle, parametric efficiency coefficient, effective gain, parametric bandwidth, gain bandwidth of the amplifier ar...