Digital holography efficiency measurements with excess noise

Area of Science:

• Optical Metrology
• Holographic Imaging Systems

Background:

• Digital holography (DH) is a powerful technique for 3D imaging and metrology.
• Understanding system efficiencies and multiplicative losses is crucial for accurate DH measurements.

Purpose of the Study:

• To quantify system efficiencies and multiplicative losses in an off-axis digital holography setup.
• To analyze the contribution of mixing efficiency, reference noise, and signal noise to overall system performance.

Main Methods:

• Utilized off-axis image plane recording geometry with a 532 nm continuous-wave laser.
• Measured mixing efficiency and reference noise efficiency to determine expected total system efficiency.
• Calculated signal-to-noise ratio (SNR) and analyzed signal noise efficiency dependence on signal strength.

Main Results:

• Measured mixing efficiency at 36.8% and reference noise efficiency at 74.5%.
• Expected total system efficiency was 22.7% ± 6.5%, with a measured efficiency of 21.1% ± 6.3%.
• Signal noise efficiency varied significantly (3%-100%) and became substantial for SNRs > 100.

Conclusions:

• Mixing efficiency is typically the primary multiplicative loss in the tested DH system.
• Excess reference and signal noise represent significant, often overlooked, multiplicative losses.
• Experimental findings align with previous theoretical and experimental results in digital holography.