Evaluation of a terahertz wave spectrum and construction of a terahertz wave-sensing system using a Yb-doped fiber laser

We experimentally evaluated a cadmium-telluride (CdTe) crystal as the nonlinear crystal for generation and detection of terahertz (THz) radiation by using a femtosecond-pulse laser. Numerical simulations based on the nonlinear Maxwell equations, including third-order optical dispersion within the spectral width of an optical pulse and absorption in the THz frequency region, well reproduce both the amplitude and phase spectra of the emitted THz wave. Excitation wavelength dependences of the THz radiation from the CdTe crystal indicate that the phase-matched condition is satisfied at a wavelength of 1000 nm. We also experimentally demonstrated a THz generation and detection system using a 1045 nm Yb-doped ultrashort-pulse fiber laser, and we verified that CdTe is one of the most suitable nonlinear crystals for a Yb-doped fiber laser.

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