Application of an optical parametric generator to cavity enhanced experiment

Abstract

The paper presents an application of an optical parametric generator (OPG) for cavity enhanced absorption spectroscopy (CEAS) technique to nitric oxide (NO) detection. The principle of this method is based on an injection of a radiation beam into an optical cavity at a very small angle. The radiation is multiple reflected inside the resonator equipped with spherical and high reflectance mirrors. After each reflection a part of the radiation leaves the optical cavity due to residual transmission of mirrors. In the case of NO detection the laser emitting at around 5.26 µm was applied. During investigation of CEAS system with OPG, two-lenses collimator was required to improve OPG beam divergence. The Ge and ZnSe lenses were used. Thanks to this decrease of about three times in beam diameter was achieved (at the distance of 1 m from source). It make it possible to measure output signal from the CEAS optical cavity. Keyword: CEAS, NO detection, optical sensor.