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

摘要

The authors made experiments on real-time imaging of THz radiation from Quantum Cascade Laser(QCL), using vanadium oxide (VOx) microbolometer infrared focal plane arrays (IRFPAs) of 320x240 withpitches of 37 μm and 23.5 um as well as 640x480 with 23.5μm pitch. The QCL has such parameters as 3.1THz emission frequency and time averaged power of about 10 μW at 15K operation temperature. Using QCLand current VOx IRFPAs, Noise Equivalent Power (NEP) was measured at 3.1 THz and found 200~300 pW.To improve NEP or THz signal, THz absorption layer was added to pixel structure of the current 320x240IRFPA with 23.5m pitch and THz transmissivity of package window was also increased. NEP values forimproved FPAs were measured and NEP value of 40 pW was obtained at 3.1 THz. Finally, effect of pixelintegration on NEP was investigated for frame integration of 64 frames and it is found that NEP value as lowas 1 pW is achievable.