Detectivity optimization to measure ultraweak light fluxes using an EM-CCD as binary photon counter array

Abstract

For a wide range of purposes, one faces the challenge to detect light from extremely faint and spatially extended sources. In such cases, detector noises dominate over the photon noise of the source, and quantum detectors in photon counting mode are generally the best option. Here, we combine a statistical model with an in-depth analysis of detector noises and calibration experiments, and we show that visible light can be detected with an electron-multiplying charge-coupled devices (EM-CCD) with a signal-to-noise ratio (SNR) of 3 for fluxes less than $$30\,{\text{photon}}\,{\text{s}}^{ - 1} \,{\text{cm}}^{ - 2}$$ 30 photon s - 1 cm - 2 . For green photons, this corresponds to 12 aW $${\text{cm}}^{ - 2}$$ cm - 2 ≈ $$9{ } \times 10^{ - 11}$$ 9 × 10 - 11 lux, i.e. 15 orders of magnitude less than typical daylight. The strong nonlinearity of the SNR with the sampling time leads to a dynamic range of detection of 4 orders of magnitude. To detect possibly varying light fluxes, we operate in conditions of maximal detectivity $${\mathcal{D}}$$ D rather than maximal SNR. Given the quantum efficiency $$QE\left( \lambda \right)$$ Q E λ of the detector, we find $${ \mathcal{D}} = 0.015\,{\text{photon}}^{ - 1} \,{\text{s}}^{1/2} \,{\text{cm}}$$ D = 0.015 photon - 1 s 1 / 2 cm , and a non-negligible sensitivity to blackbody radiation for T > 50 °C. This work should help design highly sensitive luminescence detection methods and develop experiments to explore dynamic phenomena involving ultra-weak luminescence in biology, chemistry, and material sciences.

Ultra weak photon emission—a brief review

“…The range for small numbers of photons overlap with each other and the thermal background to eliminate any exact quantitative assignment ( Zhang et al, 2009 ). Despite this, attempts have been made to use an EMCCD quantitatively by applying calibrated thresholds ( Figure 3 ) ( Khaoua et al, 2021 ).…”

Self-assembled CsPbBr3 quantum dots with wavelength-tunable photoluminescence for efficient active jamming

“…Charged-coupled devices (CCDs) have been widely used in laser imaging radar, 29,30 low light level detection, 31 missile guidance, 32 space remote sensing, 33 recognition, 34 and inspection for civilian or military purposes. 35 Countries worldwide have recognized the tremendous power and effect of photoelectric guidance devices based on CCDs and their significant role in photoelectric equipment for developing weapons.…”