Digital holography at light levels below noise using a photon-counting approach

Area of Science:

• Optics and Photonics
• Digital Holography
• Photon Counting Detectors

Background:

• Weak signal detection is challenging, especially when signals are below detector noise levels.
• Digital holography offers potential for high-resolution imaging but requires careful parameter optimization.
• Photon-counting detectors provide high dynamic range, crucial for distinguishing faint signals.

Purpose of the Study:

• To investigate the recording of weak digital holograms obscured by detector noise.
• To determine optimal holographic recording parameters under challenging signal conditions.
• To analyze the relationship between fringe visibility, signal-to-noise ratio (SNR), and holographic quality.

Main Methods:

• Utilized a photon-counting detector with high dynamic range for hologram acquisition.
• Systematically varied holographic parameters to evaluate their impact on recording quality.
• Compared experimentally obtained holographic measures with theoretically evaluated curves.

Main Results:

• Identified an optimal set of holographic parameters for recording signals below noise thresholds.
• Demonstrated that increasing fringe visibility does not consistently improve the signal-to-noise ratio (SNR).
• Showed that SNR is a more reliable indicator of holographic recording quality than visibility alone.

Conclusions:

• Optimal holographic parameters can be determined even for weak signals buried in noise.
• Fringe visibility and SNR are distinct metrics, and SNR is paramount for assessing recording quality.
• Photon-counting detectors are effective tools for high-dynamic-range digital holography of faint signals.