Half Cycle Terahertz Pulse Generation by Prism-Coupled Cherenkov Phase-Matching Method
- 248 Downloads
Nonlinear optical terahertz wave generation is a promising method for realizing a practical source with wide frequency range and high peak power. Unfortunately, many nonlinear crystals have a strong absorption in the terahertz frequency region. This limits efficient and widely tunable terahertz wave generation. The Cherenkov phase-matching method is one of the most promising techniques for overcoming these problems. We propose a prism-coupled Cherenkov phase-matching method, in which a prism with a suitable refractive index at terahertz frequencies is coupled to a nonlinear crystal. We demonstrate prism-coupled Cherenkov phase-matching terahertz generation using the DAST and LiNbO3 crystals. With a DAST crystal, we obtain a spectral flat tunability up to 10 THz by difference frequency generation. With a LiNbO3 crystal, we observe a spectral flat broadband terahertz pulse generation up to 5 THz pumped by a femto second fiber laser. The obtained temporal waveform is an ideal half cycle pulse suitable for reflection terahertz tomography.
KeywordsTerahertz wave Nonlinear optics Cherenkov phase-matching Tomography
- 8.J. Hebling, G. Almasi, I. Kozma, and J. Kuhl, “Velocity matching by pulse front tilting for large area THz-pulse generation,” Opt. Express 10, 1161–1166 (2002).Google Scholar
- 19.H. Ito, K. Miyamoto, and H. Minamide, “Ultra-broadband, frequency-agile THz-wave generator and its applications,” in Advanced Solid-State Photonics, (Optical Society of America, 2008), WD1.Google Scholar