Fig. 5
From: Broadband THz to NIR up-converter for photon-type THz imaging
Imaging quality evaluation using the modulation transfer function (MTF) and factor of signal to noise (FSNR) characterized by R/Jbg. a The modulation transfer function (MTF) of the HIWIP-LED device with the double heterojunction LED (LED #1). b The modulation transfer function (MTF) of the HIWIP-LED device with the InGaAs quantum well LED (LED #2). c Peak responsivity and the corresponding values of R/Jbg of the HIWIP-LED at low temperatures under different bias voltages. d The mapping result of R/Jbg as a function of bias and wavenumbers at 3.5 K
