Vodopyanov Konstantin L
Opt Express. 2006 Mar 20;14(6):2263-76. doi: 10.1364/oe.14.002263.
We explore optical-to-terahertz conversion efficiencies which can be achieved with femto- and picosecond optical pulses in electro-optic crystals with periodically inverted sign of second-order susceptibility. Optimal crystal lengths, pulse durations, pulse formats and focusing are regarded. We show that for sufficiently short (femtosecond) optical pulses, with a pulsewidth much shorter than the inverse terahertz frequency, conversion efficiency does not depend on pulse duration. We also show that by mixing two picosecond pulses (bandwidth-limited or chirped), one can achieve conversion efficiency, which is the same as in the case of femtosecond pulse with the same pulse energy. Additionally, when the group velocity dispersion of optical pulses is small, one can substantially exceed Manley -Rowe conversion limit due to cascaded processes.
我们研究了在二阶极化率周期性反转符号的电光晶体中，利用飞秒和皮秒光脉冲可实现的光到太赫兹的转换效率。考虑了最佳晶体长度、脉冲持续时间、脉冲形式和聚焦情况。我们表明，对于足够短的（飞秒）光脉冲，其脉冲宽度远短于太赫兹频率的倒数，转换效率不依赖于脉冲持续时间。我们还表明，通过混合两个皮秒脉冲（带宽受限或啁啾），可以实现与具有相同脉冲能量的飞秒脉冲情况下相同的转换效率。此外，当光脉冲的群速度色散较小时，由于级联过程，可以大大超过曼利 - 罗转换极限。
