Department of Chemistry and Chemical Biology, Cornell University, 122 Baker Laboratory, Ithaca, New York 14853-1301, USA.
Opt Lett. 2010 Jun 15;35(12):1962-4. doi: 10.1364/OL.35.001962.
A compact and stable method for generating high-intensity linearly polarized continuum mid-IR and terahertz light using ultrafast femtosecond (fs) laser pulses is demonstrated. Continuous light generation from <400 cm(-1) (12 THz, 25 microm) to >3300 cm(-1) (100 THz, 3 microm) in a sub-100 fs laser pulse is facilitated by nonlinear mixing of the fundamental, second harmonic, and third harmonic of an ultrafast amplified laser source through filamentation in air. Including the third harmonic in the mixing scheme leads to a tenfold increase in the generated IR power. The compact optical configuration utilizing a delay plate in a collinear geometry serves to simplify alignment and increase stability, making it a practical source for transient IR spectroscopy.
一种利用超快飞秒（fs）激光脉冲产生高强度线偏振连续中红外和太赫兹光的紧凑且稳定的方法得到了证明。通过在空气中的细丝化作用，将超快放大激光源的基频、二次谐波和三次谐波进行非线性混合，在小于 100fs 的激光脉冲中实现了从 <400cm(-1)（12THz，25μm）到>3300cm(-1)（100THz，3μm）的连续光产生。在混合方案中包括三次谐波会使产生的红外功率增加十倍。采用延迟板的共线几何结构的紧凑光学配置有助于简化对准并提高稳定性，使其成为瞬态红外光谱的实用光源。
