Comparative performance of terahertz emitters in amplifier-laser-based systems

We give an overview of opto-electronic terahertz systems based on femtosecond amplifier lasers, and present a comparison of the relative performance and design issues of the various suitable downconversion photomixers employed for the generation of intense terahertz radiation pulses in such systems. The survey includes large-area biased semiconductor antennas, large-area nonlinear optical crystals and laser-generated gas plasmas as sources for terahertz radiation. The performance of these emitters is reviewed in terms of the terahertz pulse energies achieved and their associated spectral and signal-to-noise properties.