Design of near-infrared solid-state tunable Fabry-Perot filters based on VO/P4VP films.

The significant refractive index change of VO during phase transition makes it attractive for the design of optical switches and filters, but high absorption of VO limits its development in the field of filter. In this paper, we firstly design near-infrared solid-state tunable/switchable single-/dual-band bandpass Fabry-Perot (F-P) filters based on VO/P4VP composite films using COMSOL software. The simulation results show that the single-passband tunable filter can achieve a continuous thermal tuning range of 19 nm at 1064 nm, the full width at half maxima (FWHM) is 28.8 nm, and the peak transmittance is >30%. On this basis, we simulated a tunable dual-band bandpass filter, the left peak can be heated to achieve a tuning range of 15 nm (945 nm), the right peak is 24 nm (1168 nm), the peak transmittances of both the two peaks are >35%. When boosting the VO fraction, the continuous tunability of the above-mentioned single-/dual-band filters will be switchable due to the high absorption of VO, and then switchable single-/dual-band bandpass filters are designed. This work has guiding significance for the design of novel filter structures and optical tunable devices based on phase change materials such as VO in the future.