Several methods exist for generating terahertz radiation, including:
Photoconductive Antennas: These devices use short laser pulses to excite electrons in a semiconductor material, creating a transient current that emits terahertz radiation. Optical Rectification: This process involves mixing two laser beams in a nonlinear crystal, generating terahertz radiation through the difference frequency. Quantum Cascade Lasers (QCLs): QCLs are semiconductor lasers that can be engineered to emit in the terahertz range. They rely on intersubband transitions within the conduction band of a semiconductor heterostructure. Terahertz Parametric Oscillators (TPOs): These devices use nonlinear optical materials to convert optical pump photons into terahertz photons.
