Center for Relativistic Laser Science

2019 123rd KCS

Typical pulse width of mid-IR pulse generated by OPA-dfg is limited to 200-400 cm-1 which is not enough to cover whole molecular vibration region. Generation of continuum IR pulse is useful for time-resolved spectroscopy since it makes possible to observe entire vibration region with single shot. This useful broadband pulse was generated by simple colinear geometry of three pulses. Fundamental pulse passes 2 nonlinear crystals generating second harmonic and third harmonic pulse by nonlinear optical processes. Fundamental pulse with second harmonic and third harmonic pulses are focused in the air. Intense laser pulse induces the air break down into plasma. In the air-plasma, three laser pulses are mixed to generate continuum IR. Applications of continuum IR pulse would be such as multidimensional spectroscopy and IR pump-probe microscopy.