THz generation by optical rectification and competition with other nonlinear processes
نویسنده
چکیده
We present a study of the terahertz (Tilz) generation by optical rectification in a 2 mm thick <110> ZnTe crystal. The conditions for the most efficient THz generation are described. We investigate the competition between optical rectification (OR), second harmonic generation (SHG), two photon absorption (TPA) and free-carrier absorption in the diffraction limit, for excitation spot sizes smaller than the THz wavelength. We find that while free-carrier absorption contributes significantly to reduce the THz emission, this contribution does not depend on the excitation spot size. On the contrary, two photon absorption induces a strong dependence of the THz emitted power for decreasing excitation sizes.
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