Principles of THz Generation
The theoretical background of terahertz generation by photomixing will be discussed in detail. Basic design rules are specified for obtaining highly efficient optical to THz power conversion for both photoconductive and high frequency p-i-n diodes, considering pulsed as well as continuous-wave operation. State-of-the-art realizations of photomixers at 800 and 1550 nm laser wavelength are shown. Limiting electrical and thermal constraints to the achievable THz power are also addressed. Finally, this chapter gives an overview of electronic means for THz generation, such as Schottky diodes, negative differential resistor oscillators, and plasmonic effects that are used in THz generation. The chapter starts with a quick overview of the most relevant THz generation schemes based on nonlinear media, accelerating electrons, and actual THz lasers. This serves to place in context the two schemes discussed in detail thereafter: photomixing and electronic generation. The chapter covers the theoretical frameworks, principles of operation, limitations, and reported implementations of both schemes for pulsed and continuous-wave operation when applicable. It also covers to a lesser extent the recently explored use of plasmonics to improve the efficiency of THz generation in photomixing, nonlinear media, and laser schemes.
& Navarro-Cía, M.
(2015). Principles of THz Generation. Semiconductor THz Technology: Devices and Systems at Room Temperature Operation, 3-68.