Аннотация:Optical properties of carbon dioxide in the vicinity of its critical point were studied. Amplitude-frequency characteristics of radiation backscattered in CO2 have been studied using laser Doppler velocimeter based on highly stabilized Nd:YAG3+ chip-laser. Significant (up to 10 times) narrowing of backscattered radiation spectrum and increasing of its amplitude (up to 100 times) in the vicinity of critical point were detected and analyzed. Nonlinear temperature dependence of reflection from glass- CO2 interface was observed. Intrinsic anomaly of light reflection of critical media was revealed. Transmission spectrum of cell with critical CO2 was measured in 0.35- 1 micrometers spectral range. Formula for integral spectrum of light scattered in near-critical medium was obtained.