Interferometric Sensor of Wavelength Detuning Using a Liquid Crystalline Polymer Waveplate.

Research paper by Paweł P Wierzba

Indexed on: 14 May '16Published on: 14 May '16Published in: Sensors (Basel, Switzerland)


Operation of a polarization interferometer for measurement of the wavelength changes of a tunable semiconductor laser was investigated. A λ/8 waveplate made from liquid crystalline polymer is placed in one of interferometers' arms in order to generate two output signals in quadrature. Wavelength was measured with resolution of 2 pm in the wavelength range 628-635 nm. Drift of the interferometer, measured in the period of 500 s, was 8 nm, which corresponded to the change in the wavelength of 1.3 pm. If needed, wavelength-dependent Heydemann correction can be used to expand the range of operation of such interferometer.