Detectivity optimization to detect of ultraweak light fluxes with an EM-CCD as binary photon counter array

Area of Science:

• Optics and Photonics
• Scientific Instrumentation

Background:

• Detecting extremely faint and extended light sources presents significant challenges, often dominated by detector noise over source photon noise.
• Quantum detectors operating in photon counting mode are crucial for such applications.

Purpose of the Study:

• To demonstrate the capability of electron-multiplying charge-coupled devices (EM-CCDs) for detecting ultra-weak light signals.
• To analyze detector noise and calibration for optimizing sensitivity.

Main Methods:

• Combined a statistical model with in-depth analysis of detector noises.
• Conducted calibration experiments to validate performance.
• Operated the EM-CCD in conditions of maximal detectivity for varying light fluxes.

Main Results:

• Achieved a signal-to-noise ratio (SNR) of 3 for light fluxes below 12 aW (green photons).
• Demonstrated a dynamic detection range of 4 orders of magnitude due to SNR nonlinearity with sampling time.
• Identified non-negligible sensitivity to blackbody radiation above 50°C.

Conclusions:

• EM-CCDs are highly effective for detecting ultra-weak light, significantly advancing luminescence detection.
• The findings facilitate the design of sensitive methods for exploring dynamic phenomena in biology, chemistry, and material sciences.
• Understanding detector noise and operating conditions is key to maximizing sensitivity.