Electro-tunable optical cavity filters in near-infrared regime

The design, simulation, and fabrication of two electrically tunable Fabry-Perot (FP) microcavities filled with Twisted Nematic Liquid Crystal (TNLC), based on different mirror materials are demonstrated theoretically and experimentally in the near-infrared (NIR) regime. Owing to the polarization-independent property of TNLC, the wavelength-selection and tunable property of the Liquid Crystal Tunable Filter (LCTF) is independent on polarization state of incoming light beam in the tuning range. The experimentally measured full width at half maximum (FWHM) of the first aluminum mirrors device at a voltage of 10.39 V is -2.5 nm while the other device composed of gold mirrors showed -5.5 nm at an applied voltage of 12.72 V. An overall -53.6 nm spectral shift is observed in first device at 12.72 V with seven and five distinct spectral channels are found with an overall spectral shift of -27.9 nm at 15.29 V applied voltage in second device over the desired spectral band. The simulated work on LCTFs is found in complete agreement with experimental results.

Automated summary

Two electrically tunable Fabry-Perot microcavities filled with Twisted Nematic Liquid Crystal (TNLC) based on different mirror materials were designed, simulated, and fabricated in the near-infrared (NIR) regime. The Liquid Crystal Tunable Filter (LCTF) demonstrated wavelength-selection and tunable properties independent of polarization state of incoming light beam. Experimental results showed spectral shifts and distinct spectral channels, in agreement with simulated results.