Semiconductors as Highly Efficient Single and Multicycle Terahertz Sources

The low-(0.1-2 THz) and mid-frequency (2-20 THz) bands of the THz range can be accessed by optical rectification (OR) in LiNbO
₃
(LN) [1] and organic crystals [2], respectively. The low-frequency band is optimally fitting for acceleration of charged particle beams. However, further increasing the THz pulse energy and field strength is challenging.