In this paper, a 1064 nm pulsed laser source and a short-wave IR (SWIR) camera are used to measure the total system efficiency associated with a digital holography system in the off-axis image plane recording geometry. At a zero path-length difference between the signal and reference pulses, the measured total system efficiency (15.9%) is consistent with that previously obtained with a 532 nm continuous-wave laser source and a visible camera [Appl. Opt. 58, G19 (2019)APOPAI0003-693510.1364/AO.58.000G19]. In addition, as a function of the temporal delay between the signal and reference pulses, the total system efficiency is accurately characterized by a component efficiency, which is formulated from the ambiguity function. Even with multimode behavior from the pulsed laser source and substantial dark current noise from the SWIR camera, the system performance is accurately characterized by the resulting ambiguity efficiency.
A digital-holography (DH) system is created in a heterodyne-pulsed configuration, meaning that the reference and signal pulses are nondeterministically correlated in time. Using the off-axis image plane recording geometry, two performance metrics are measured: (1) the total-system efficiency and (2) the ambiguity efficiency. These metrics are compared against the same measured efficiencies for a DH system in a homodyne-pulsed configuration, which uses deterministically correlated reference and signal pulses. The total-system efficiency of both systems is found to be consistent with one another, showing that no new component efficiencies are required when switching from a homodyne-to a heterodyne-pulsed configuration. Additionally, an instantaneous phase modulation model is used to characterize system performance in terms of nonideal pulse overlap. Such a model validates the use of the ambiguity efficiency for future efforts.
Using a pulsed configuration, a digital-holographic system is setup in the off-axis image plane recording geometry, and spectral broadening via pseudo-random bit sequence is used to degrade the temporal coherence of the master-oscillator laser. The associated effects on the signal-to-noise ratio are then measured in terms of the ambiguity and coherence efficiencies. It is found that the ambiguity efficiency, which is a function of signal-reference pulse overlap, is not affected by the effects of spectral broadening. The coherence efficiency, on the other hand, is affected. As a result, the coherence efficiency, which is a function of effective fringe visibility, is shown to be a valid performance metric for pulsed-source digital holography.
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