Long-range frequency domain low-coherence interferometry detector for industrial applications

Cerrotta, Santiago; Torga, Jorge; Morel, Eneas N.

doi:10.1364/josaa.478870

Cited by 2 publications

(1 citation statement)

References 22 publications

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“…Other tradeoffs of this strategy include significant post-processing to reconstruct the extended depth and extract the relevant signal and, in some implementations, reduced imaging rate for otherwise MHz-rate time-stretch sources. Alternatively, down-conversion has been achieved using translation stages and multiple interferometers [ 16 , 17 ]. Translation stages have been used by our group and others to achieve a variable working distance range of several centimeters through maintenance of the optical pathlength difference [ 6 , 7 ].…”

Section: Introductionmentioning

confidence: 99%

Electronic frequency shifting enables long, variable working distance optical coherence tomography

Wisniowiecki,

Applegate

2023

Biomed. Opt. Express

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Increased imaging range is of growing interest in many applications of optical coherence tomography to reduce constraints on sample location, size, and topography. The design of optical coherence tomography systems with sufficient imaging range (e.g., 10s of centimeters) is a significant challenge due to the direct link between imaging range and acquisition bandwidth. We have developed a novel and flexible method to extend the imaging range in optical coherence tomography using electronic frequency shifting, enabling imaging in dynamic environments. In our approach, a laser with a quasi-linear sweep is used to limit the interferometric bandwidth, enabling decoupling of imaging range and acquisition bandwidth, while a tunable lens allows dynamic refocusing in the sample arm. Electronic frequency shifting then removes the need for high frequency digitization. This strategy is demonstrated to achieve high contrast morphological imaging over a > 21 cm working distance range, while maintaining high resolution and phase sensitivity. The system design is flexible to the application while requiring only a simple phase correction in post-processing. By implementing this approach in an auto-focusing paradigm, the proposed method demonstrates strong potential for the translation of optical coherence tomography into emerging applications requiring variable and centimeter-scale imaging ranges.

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