Pulsed laser source digital holography efficiency measurements

Abstract

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.

Digital-holography efficiency measurements using a heterodyne-pulsed configuration

“…To this end, the effect of temporal delay between the reference and signal pulses was recently studied using a 1064-nm pulsed laser source and a short-wave infrared (SWIR) camera. 18 These experiments showed that the measured total-system efficiency was comparable to that of a DH system in a CW configuration. It also introduced a novel component efficiency, called the ambiguity efficiency, to capture the effects of reduced pulse overlap.…”

“…( 1). Both efficiencies are described in detail elsewhere 13,16,18 and are not of primary concern in this paper. The mixing efficiency, however, merits additional consideration, since it quantifies of how well the reference and signal pulses interfere.…”

“…18 The polarization efficiency is the quantification of how well the polarization axes of the reference and signal pulses align, and the modulation efficiency is a quantification of how well the finite pixels of the FPA record the continuous hologram. As with η ern and η snl , η pol and η mod are discussed in detail elsewhere 13,17,18 and are not of primary concern in this paper. In contrast, η amb is a main focus of this paper as it is the only efficiency dependent on the temporal overlap between the reference and signal pulses.…”

“…With the outcomes of Ref. 18 in mind, more research is still required to fully characterize DH systems in a pulsed configuration. In response, this paper presents two-novel contributions to expand the understanding of such systems.…”

“…In the previous work, the signal and reference pulses were deterministically correlated, since a postamplification beam splitter was used to create the two fields of light being interfered from a single-pulse train. 18 This idealization isolated the effect of reduced pulse overlap by ensuring the temporal characteristics of the reference and signal pulses were identical before interaction with the experiment. Thus this previous configuration is referred to as the "homodyne-pulsed configuration" throughout this paper.…”