Ultrasensitive intracavity molecular spectroscopy for diagnostic applications

Intracavity laser spectroscopy (ILS) presents itself as a highly effective technique that allows one to detect the change of light signal from absorbing molecules at a level of radiation quantum noise. Thus high sensitivity of ICLS allows one to determine the absorbing molecules concentrations in gases and liquids in the range between 10 -6 to 10 -10 . The potential of ICLS technique employment for establishing interrelations between small changes in the breathed air caused by diseases in the early stage, as well as a mass screening of patients with diseases of the liver and kidneys by acetone and urea detection in breathed air, and with heart diseases by measurement of CO 2 concentration is discussed. Usage of gas, dye and solid-state lasers for such measurements is analyzed, optimum spectral ranges are presented.