【摘要】 用1.06μm微微秒激光脉冲序列按一定角度激励LiIO₃晶体,在4896～6119（?）可见光区内获得8种波长相干喇曼混频辐射,这个复杂受激喇曼散射过程可解释为:在满足位相匹配的条件下,1.06μm强光束一方面与其散射光按非共线型产生二次谐波;另一方面又在晶体形成激元的相干激发,后者对倍频光散射而得到一阶以及高阶的斯托克斯辐射和反斯托克斯辐射,这是二阶与三阶非线性光学过程的综合效应.此外,我们观察到反向的受激散射,其光谱成分与正向的成分不同.并证明,与普通的后向散射也不同,它是1.06μm入射光在晶体出射端面的反射光所产生的谐波相干喇曼混频.更多还原

【Abstract】 By pumping a LiIO3 crystal with 1.06μm picosecond laser pulses train at a proper incident angle, 8 stimulated Raman scattering lines have been obtained at the visible region from 4896 A to 6119A:ω=2ω1±nωP, n = 1, 2, 3, concerned elementary excitations being LO mode and TO mode of (A+E1) oblique polariton in the crystal. The process of such a complex stimulated Raman scattering is as following: with phase matching intense 1.06?m laser beam and its scattering light generate SHG in the crystal;meanwhile it excites coherently the elementary excitations of the crystal, the latter scatter the SHG into Stokes and antistokes radiations resulting in a complex effect of x(2) and x(3) nonlinear optical process. Furthermore the reflected ward stimulated Raman scattering with distinct wavelength has been observed from the forward one. Present paper shows that the reflectedward scattering is also the SHG coherent Raman mixing but generated by the 1.06μm beam reflected upon the exit crystal surface.更多还原