Crosstalk elimination by rearranging thin-film filters

Abstract

Patterned thin-film Fabry–Pérot filters are used to develop compact spectral cameras. Recent articles report on crosstalk in such devices, raising concerns regarding spectral and spatial resolution. It has been suggested that light entering a filter might spill over to neighboring filters but this has not yet been analyzed in detail. The proposed mechanism in this Letter is that the Fabry–Pérot filters act as coupled waveguides that can propagate crosstalk above the pixel array. The results show that the crosstalk can be asymmetric, enabling elimination by rearranging the filters on the sensor. Interestingly, the logical strategy where crosstalk to all neighbors is eliminated appears suboptimal due to additional resonances. These findings reveal untapped opportunities for developing better sensors and a corresponding need for further systematic investigations.