Date of Award
Doctor of Philosophy (PhD)
Department of Engineering Physics
Glen P. Perram, PhD
The efficiencies of a digital holography (DH) system in the pulsed configuration and the off-axis image plane recording geometry are analyzed. First, the system efficiencies of an infrared-wavelength DH system in a homodyne-pulsed configuration are measured and compared to those of a visible-wavelength DH system in a homodyne-continuous-wave (CW) configuration. The total-system, excess-reference-noise, shot-noise-limit, and mixing efficiencies of the pulsed-source system were found to be consistent with those of the CW-source system. This indicated no new efficiencies were necessary to characterize pulsed-source systems when no temporal delay exists between the pulses. The consistency of efficiencies also showed infrared DH systems are viable but degraded due to infrared detector technology. A new efficiency, called the ambiguity efficiency, was introduced to account for the degradation in system performance as the temporal delay between the pulses increased. This novel efficiency was then experimentally verified. Second, a DH system in the heterodyne-pulsed configuration was characterized in terms of the total-system and ambiguity efficiencies. The efficiencies measured using a heterodyne-pulsed configuration were consistent with those measured using a homodyne-pulsed configuration. Therefore, there was no degradation in system performance by changing from a homodyne configuration to a heterodyne configuration. This will allow the effective range of pulsed-source DH systems to greatly increase. Third, the effect of spectrally broadening the source laser of a DH system in the heterodyne-pulsed configuration was analyzed. Experiments showed the ambiguity efficiency was not significantly affected by the degradation in temporal coherence. However, the total-system efficiency did change as a function of temporal coherence degradation.
DTIC Accession Number
Owens, Steven A., "Efficiency Quantification for Pulsed-source Digital Holographic Wavefront Sensing" (2022). Theses and Dissertations. 5539.