2025/05/12 by Ogawa, Kotaro, Kanda, Natsuki, Murotani, Yuta +3 · 1 citation
#FOS: Physical sciences #Optics (physics.optics)
paper · doi:10.48550/arxiv.2505.07242
Gallium selenide (GaSe) is an efficient nonlinear crystal for electro-optic (EO) sampling in the multi-terahertz (THz) frequency range. However, the lattice resonance at several THz frequencies hampers broadband EO sampling, resulting in distorted pulse waveforms. In this work, we experimentally evaluated the frequency-dependent response function in EO sampling, considering the effects of phonons, phase mismatch, and gate pulse waveforms. The phonon effect is described using an effective Faust-Henry coefficient, which was determined to be -0.21 ± 0.02. The corrected field amplitude of multi-THz pulses aligns with additional measurements of average power and a beam diameter. The successful compensation of the frequency characteristics in GaSe will contribute to a more accurate evaluation of multi-THz transients.