In the optics laboratory, the main activity has been the development of the cavity ring down (CRD). Furthermore the laboratory is equipped with optical tables, fast visible and near infrared sensors, fast optical switches and tunable lasers with fibre coupling. The cavity ring down technique uses the accumulation of laser pulses in a resonant cavity with high reflective mirrors to measure very small absorptions at different wavelengths. With this technique several sensors have been developed, for explosives (ISOTREX), for formaldehyde (AMBIMAT) and other gases. In collaboration with INAF a CRD apparatus for high pressures has been constructed for the study of planetary atmospheres and a heatable/coolable high pressure atmospheric simulation chamber for optical measurements (PARSIFAL) is presently in construction.