Simple device to measure laser mirror parameters

In the proposed design of the spectrometer provision has been made to measure the reflectivity, transmittance and scattering factor of laser mirrors and their grass blanks before actual coating. The spectrometer is in the form of a double beam ratio recording system and works on the principle of modulation radiometry. The design is expected to provide lover value of uncertainty. on the order of 5 part in 10000 in the measurements, because of use of integrating sphere, sold state signal processing electronics and single photodetector. The remarkable features of this design are:ambient light doesnot affect the measuremets and care has been taken to reduce the effects of source fluctuations and polarisation due to presence of optical components.