ABSTRACT
A nonresonant electro-optic (EO) process is one of the simplest methods for both THz generation with optical rectification and detection using the EO sampling technique. It is because the optimization of nonlinear crystals is well established, even in the long-wavelength region. Nonlinear crystals are widely used for emitters and detectors using two narrowband optical beams [1]. However, I focus on broadband THz pulse generation and detection using ultrashort optical pulses here. The recent development of laser technologies provides extremely intense optical pulses or extremely ultrashort (pulse duration is less than 10 fs) optical pulses. By using materials with an instantaneous optical nonlinear response, it may be possible to capture much of this enormous bandwidth above 100 THz [2]. Moreover, high conversion efficiency of emitted THz radiation is retained even under significantly high-power excitation.
The field amplitude of output THz pulses above 1 MV/cm is reported using optimized nonlinear crystals [3]. In this chapter, I summarize the fundamentals of THz pulse generation and detection using nonlinear crystals and the ultrashort optical pulse. In Section 2.1, I review the techniques of THz pulse generation and introduce that the phase-matching condition is critical for the generation efficiency and its bandwidth of the THz pulse. In Section 2.2, I show the details of the EO sampling technique. 2.1 THz Pulse Generation from a Nonresonant
