Photocurrent Measurement of PC and PV HgCdTe Detectors
George P. Eppeldauer, R J. Martin
Novel preamplifiers for working standard PC and PV HgCdTe detectors have been developed to maintain the spectral responsivity scale of the National Institute of Standards and Technology (NIST) in the wavelength range of 5 m to 20 m. The linear PC mode preamplifier does not need any compensating source to zero the effect of the detector bias current for the preamplifier output. The impedance multiplication concept with a positive feedback buffer amplifier was analyzed and utilized in a bootstrap transimpedance amplifer to measure photocurrent of a 200 ? shunt resistance photodiode with a maximum signal gain of 108 V/A. In spite of the high performance lock-in used as a second-stage signal-amplifier, the signal-to-noise ratio had to be optimized for the output of the photocurrent preamplifiers. Noise and drift were equalized for the output of the PV mode preamplifier. The signal gain errors were calculated to determine the signal frequency range where photocurrent-to-voltage conversion can be performed with very low uncertainties. For the design of both PC and PV detector preamplifiers, the most important gain equations are described. Measurement results on signal ranges and noise performance are discussed.
and Martin, R.
Photocurrent Measurement of PC and PV HgCdTe Detectors, Journal of Research (NIST JRES), National Institute of Standards and Technology, Gaithersburg, MD
(Accessed March 5, 2024)