Capabilities of Autodyne Reception in Medical СО2 Laser Devices

The generation characteristics and the capabilities of autodyne reception in single mode CO2 lasers with pulse-periodic pumping of the active medium used in medical laser devices are investigated. It has been demonstrated that medical laser device based on CO2 laser model DIAMOND C-30A (Coherent Сo.) has the best long-term laser power stability ((2–3)%), while the setup with CO2 laser model 48–2W (Synrad Сo.) has the best short-term stability (0.62%). Amplitude-frequency characteristics of autodyne reception were studied for lasers of these devices. Power spectra of the autodyne signal appearing during evaporation of fat and muscle tissues under CO2 laser radiation of the three types of laser devices were recorded. It has been shown that all these laser devices allow to detect the autodyne signal during evaporation of biological tissues. The medical laser setup with CO2 laser model 48–2W has the highest signal-to-noise ratio during detection of laser backscattered radiation. This is due to the fact that this laser has larger autodyne amplification and better short-term power stability. The results can be used in the development of smart laser surgical systems with feedback.