Digital holography experiments with degraded temporal coherence

Thornton, Douglas E.; Mao, Davin; Spencer, Mark F.; Rice, Christopher A.; Perram, Glen P.

doi:10.1117/1.oe.59.10.102406

Cited by 11 publications

(14 citation statements)

References 24 publications

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“…We do so at various FPA integration times and path-length differences between the signal and reference. Like in the previous experiments [10], [11], these efficiencies contribute to the overall mixing efficiency. New to this paper, however, is the fact that both the vibration efficiency and the coherence efficiency depend on the FPA integration time.…”

supporting

confidence: 66%

“…In further experiments, we investigated the multiplicative losses due to coherence [11]. These experiments were significant because our results showed that the coherence efficiency, which is another efficiency that makes up the overall mixing efficiency, decreases quadratically with fringe visibility and that our measurements agreed well with our models.…”

supporting

confidence: 63%

“…The experimental setup and data processing is similar to that in Refs. [10] and [11], where additional details may be found. Figure 1 shows the experimental setup.…”

Section: Experimental Methodsmentioning

confidence: 99%

“…In the experiment, we used a cw, single-longitudinal-mode, Cobalt Samba diodepumped solid-state laser with a wavelength of 532 nm as the MO laser. This laser provided 1W of power with a vendor specified linewidth <1 MHz and a coherence length c > 100 m. From previous work [11], we characterized the MO laser linewidth as ν < 500 kHz, which corresponded to a minimum c > 260 m and a minimum τ c > 875 ns. We also used a Faraday isolator (FI) to prevent unwanted back reflection into the laser.…”

Section: Experimental Methodsmentioning

confidence: 99%

“…In both of these previous experiments [10], [11], we chose the FPA integration time based on the magnitude and stability This work is licensed under a Creative Commons Attribution 4.0 License. For more information, see https://creativecommons.org/licenses/by/4.0/ of the SNR to minimize environmental factors.…”

mentioning

confidence: 99%

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Impacts of Laboratory Vibrations and Laser Flicker Noise on Digital Holography

Thornton

Spencer

Rice

et al. 2020

IEEE J. Quantum Electron.

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In this paper, we experimentally demonstrate the impacts of laboratory vibrations and laser flicker noise on digital holography (DH). Specifically, we measure both the vibration efficiency and the coherence efficiency of our DH system at various focal-plane array integration times and path-length differences between the signal and reference. These efficiencies, in practice, contribute to the overall mixing efficiency, which is a measure for how well the detected signal and reference interfere. The results show that when the integration time is ≤1 ms, the laboratory vibrations are negligible with a vibration efficiency of 100%; however, when the integration time equals 100 ms, the laboratory vibrations lead to a 94% vibration efficiency. In addition, the results show that the effective coherence length of the master-oscillator (MO) laser increases by 280% when the integration time decreases from 100 ms to 100 µs. To account for this outcome, we present a model of the coherence efficiency based on the frequency noise of the MO laser. The model fit to the DH data then shows that the frequency of the MO laser is flicker-noise dominated. As a result, decreasing the integration time improves the overall mixing efficiency because of highpass filtering in both the vibration efficiency and the coherence efficiency. Based on previous published efforts, these results have direct ties to the achievable signal-to-noise ratio of a DH system.

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supporting

confidence: 66%

supporting

confidence: 63%

“…The experimental setup and data processing is similar to that in Refs. [10] and [11], where additional details may be found. Figure 1 shows the experimental setup.…”

Section: Experimental Methodsmentioning

confidence: 99%

Section: Experimental Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

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Impacts of Laboratory Vibrations and Laser Flicker Noise on Digital Holography

Thornton

Spencer

Rice

et al. 2020

IEEE J. Quantum Electron.

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Spectral Broadening Effects on Pulsed-Source Digital Holography

Owens

Spencer

Perram

2023

IEEE J. Quantum Electron.

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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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Digital-holography efficiency measurements using a heterodyne-pulsed configuration

2022

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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.

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Digital holography experiments with degraded temporal coherence

Cited by 11 publications

References 24 publications

Impacts of Laboratory Vibrations and Laser Flicker Noise on Digital Holography

Impacts of Laboratory Vibrations and Laser Flicker Noise on Digital Holography

Spectral Broadening Effects on Pulsed-Source Digital Holography

Digital-holography efficiency measurements using a heterodyne-pulsed configuration

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