中国物理B ›› 2010, Vol. 19 ›› Issue (3): 34209-034209.doi: 10.1088/1674-1056/19/3/034209
张喜鹏, 蒋红兵, 陈利, 蒋莹莹, 杨宏, 龚旗煌
Zhang Xi-Peng(张喜鹏), Jiang Hong-Bing(蒋红兵)†, Chen Li(陈利), Jiang Ying-Ying(蒋莹莹), Yang Hong(杨宏), and Gong Qi-Huang(龚旗煌)‡
摘要: We present an experimental investigation of a filamentation-assisted fourth-order nonlinear optical process in KTP crystals pumped by intense 1.53~eV (807~nm) femtosecond laser pulses. Femtosecond light pulses at 2.58~eV (480~nm) are generated by the fourth-order nonlinear polarization (P4(ω 2 ) = χ 4(ω 2 ,ω ,ω ,ω ,- ω 1 )E3(ω )E* (ω 1 ), where E(ω ) corresponds to the pump frequency and E(ω 1 ) to the supercontinuum generated through filamentation). If the system is seeded by a laser beam at ω 1 or ω 2 and there are spatial and temporal overlaps with the pump beam, E(ω 1 ) and E(ω 2 ) are simultaneously amplified. When the intensity of the seed laser beam exceeds a certain intensity threshold, the contribution of P4(ω ) = χ 4(ω ,ω 1 ,ω 2 ,-ω, - ω )E(ω 1 )E(ω 2 )(E* (ω))2 becomes non-negligible, and the amplification weakens. The conversion efficiency from the pump to the signal at 2.58~eV (480~nm) attains to 0.1%.
中图分类号: (Nonlinear optical crystals)