講演情報
[10p-A22-9]Reference-Free Parametric Phase Interference via Backward Nonlinear Mixing
〇(D)Yuto Yoneda1,2, Yuma Takida2, Alexander De Los Reyes2, Hirokazu Kobayashi3, Hiroaki Minamide2 (1.Chiba Univ., 2.RIKEN, 3.Kochi Univ. of Tech.)
キーワード：
Terahertz photonics、phase interference、backward wave oscillator
We report reference-free sub-THz phase interference by optical up-conversion through backward nonlinear mixing in periodically poled lithium niobate (PPLN). In conventional phase-sensitive THz-wave measurements, an externally synchronized optical reference is required to define the phase. In our scheme, a backward THz-wave parametric oscillator (BW-TPO) generates a coherent pair of a 0.304-THz wave and a near-infrared idler. By injecting only this pair into a second PPLN crystal, backward difference-frequency generation (BW-DFG) and backward sum-frequency generation (BW-SFG) are induced, and the THz-wave phase is converted into optical intensity modulation. The BW-DFG and BW-SFG signals are modulated with the THz-wave period, and FFT analysis shows clear 0.304-THz components. This result demonstrates high-contrast, frequency-selective, external-reference-free phase readout and suggests that coherence preserved in the generated idler plays a key role in backward parametric conversion.