Laser optical sensor measuring method for determining refractive indices - introducing varying refractive index medium to cause frequency shift or modulation of solid state laser

摘要

The refractive indices measuring method involves varying the optical wavelength of a diode-pumped solid state laser resonator by introducing a medium with varying refractive index. The refractive index variation is measured as a direct frequency modulation of the sensor laser. The laser signal is frequency shifted or modulated in proportion to the deflection of a sensor, and coherently optically superimposed with a reference laser signal. The difference between their frequencies or modulations is proportional to the refractive index change. The reference laser is housed in the same medium as the sensor laser so that they both experience some temp. effects. USE/ADVANTAGE - For measuring refractive indices of gases or liquids, e.g. for measuring conc. of mixtures. Compact measurement arrangement.