We present an overview of the main results of long-term collaboration between the Institute of Atmospheric Optics and the Institute of Laser Physics in development and design of a series of laser sensors-gas analyzers based on differential resonance photoacoustic detectors and a waveguide continuous-wave (CW) СО2 laser with the computer-controlled wavelength tuning. Basic elements of the gas analyzers and their characteristics are described along with examples of application to analysis of molecular compounds in air and biosphere-atmosphere exchange processes.