Quantum efficiency measurements of (EM)CCD cameras: high spectral resolution and temperature dependence

Abstract

Nowadays, CCD cameras can be found in every optical laboratory for highly diverse purposes. Measuring quantitatively spectral-dependent intensities implies that the spectral quantum efficiency (SQE) has to be taken into account, at least if the width of the spectrum is more than a few nm. The determination of the SQE is usually considered to be a tedious challenge with rather inaccurate results. However, we show in this paper that with calibrated photo diodes, this has become an affordable and straightforward task. In this paper, we examined the SQE of one front- and five back-illuminated electron multiplying CCD cameras from Andor Technology in the range of 350–1080 nm with a spectral resolution of up to 1 nm. The temperature dependence of the SQE has been investigated in the spectral interval given above between +20 and −80 °C. We observed unexpected oscillations in the SQE for the front-illuminated camera. For back-illuminated cameras with an ultraviolet conversion layer, the measured SQE turns out to be very different from the manufacturer data, which results from the transmittance spectrum of the conversion layer. For conventional back-illuminated cameras without a conversion layer, we observed interesting crossing behavior in the temperature-dependent measurements.