INFORMATION CAPACITY AND ENERGETIC EFFICIENCY OF HIGH-SPEED TIME-DOMAIN FULL-FIELD OPTICAL COHERENCE TOMOGRAPHY SYSTEM
To study the internal microstructure of layered semitransparent objects a high-speed full-field time-domain optical coherence tomography system based on a Linnik microinterferometer was created.
The modified optical system of the microinterferometer provides 5 times magnification and linear field of view at object space equaled 1.2 mm. The reference arm of the interferometer allows installation of reflectors with different reflectivity coefficient. Scanning of a sample within depth of 1 mm is carried out using a computer-controlled PI M-501 positioner with asynchronous recording of video frames on a matrix photodetector.
The dynamic range for various configurations of the system was calculated: with the powerful LED (ARPL-STAR-3W, wavelength 630 nm) or a halogen lamp and recording on IDS UI 3060CP video camera, as well as when using a high-power near infrared illumination and Xenics Xeva 1.7 640 video camera during examination of the samples with the reflection coefficient less than 0.01. The analysis shows that the considered systems provide signal-to-noise ratio in the range of 20-40 dB if the source power exceeding 100 mW and video recording rate does not exceed 500 frames per second. For multiple long-term scanning of living biological samples it is recommended to use sources with optical power that is less than 400 mW, since this does not exceed the maximum allowable radiation power density on the samples.
The obtained evaluations demonstrate that the energy efficiency of the opto-electronic system is sufficient to obtain information about three-dimensional structure of a sample within depth of 1 mm, but the speed limitation of the video camera USB interface allows visualization only after post processing of the recorded data. For real-time visualization of the three-dimensional structure (up to 10 frames per second), it is necessary to use video cameras with the high-speed recording interface, for example, PCIe Gen3, with subsequent online processing of the data in the computer's RAM.
The work was financially supported by the Russian Science Foundation (Grant No. 19-79-10118)
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