Detection of terahertz radiation from quantum cascade laser using vanadium oxide microbolometer focal plane arrays

Abstract

The authors tried real-time imaging of THz radiation from Quantum Cascade Laser (QCL), using vanadium oxide (VOx) microbolometer focal plane arrays (FPAs) of 320x240 with pitches of 37 μm and 23.5 μm as well as 640x480 with 23.5μm pitch. The QCL has such parameters as 3.1 THz emission frequency (97μm in wavelength), 300-400 nsec pulse width, 1.07 msec repetition period, 30 mW peak intensity, 15K operation temperature. The THz radiation from QCL is collimated by off-axis parabola (OAP) and focused on FPA by another OAP. The 10 μm range infrared radiation from scene is blocked by sapphire disk or metal mesh filter. Noise Equivalent Power (NEP) at 3.1 THz is estimated to be 200~400 pW.