Abstract

The sensitive detection of terahertz (THz)-wave radiation from compact sources at room temperature is crucial for real-world THz-wave applications, such as non-destructive inspection and homeland security. As an extremely compact THz-wave source, the resonant-tunneling-diode (RTD) oscillator is a particular important electronic device operating in the THz-wave frequency region. The oscillation frequency of RTD is now close to 2 THz with improvements in their structures [1]. For detecting THz-wave radiation from RTDs at room temperature, frequency up-conversion in nonlinear optical crystals is a promising technique because the input frequency and power of RTD can be calibrated by measuring the output wavelength and energy of up-converted waves, respectively. In the up-conversion process, the THz-wave radiation (ω_THz) is mixed with an optical pump wave (ω_p) in a nonlinear crystal to generate an optical up-converted wave (ω_up) according to the energy conservation law (ω_p = ω_up + ω_THz) [2,3]. The generated up-converted wave is detected using a commercial photodetector with nanosecond resolution. This optical approach differs from conventional room-temperature THz-wave direct detectors, such as the pyro-electric detector and Golly cell, which offer slow response time on the order of millisecond.

© 2017 IEEE