Extraction of the Information Component of the Autodyne Signal in Pulsed-periodic CO2 Lasers for Doppler Diagnostics of the Surgical Process

Alexey Konovalov, Valerii Ulyanov
Vol. 10 (2021) p.129-137

The creation of laser surgical systems with feedback, which allows performance of high-precision low-trauma operations, is the current trend of modern surgery. CO2 lasers with pulse-periodic pumping which generate radiation at a wavelength of 10.6 µm and modulated at a frequency of 5–20 kHz are widely used in medical practice. This paper reports the possibility of creating feedback based on the autodyne effect that occurs in such surgical CO2 lasers during laser dissection/evaporation of biotissues. The algorithm for extracting the information component (Doppler signal) of the autodyne signal for such CO2 lasers has been developed. We showed that application of this algorithm permits extraction of the Doppler component spectrum in the autodyne signal that occurs when dissecting biotissues. Doppler signals were obtained when dissecting pig tissues in vitro, with a signal-to-noise ratio in the range of 5–15. The results obtained can be used in the development of smart laser surgical systems with feedback.