Dynamically-Tunable Narrowband Color Sensor Compatible With CMOS Technology

Color sensors have broad applications in spectroscopy, medical imaging, and CMOS-based cameras. One of the fundamental challenges in this field is implementing a dynamically tunable filter capable of covering the visible spectrum; hence, designing a tunable filter with high spectral resolution and a narrow bandwidth frequency response is essential. In this work, a multilayer color sensor based on Fabry-Pérot resonance is designed, offering the capability for static and dynamic tuning of the transmitted wavelength and the ability to detect different colors in an integrated device, including a filter and detector. The filter comprises four parts: blue, green, yellow-orange, and red. The detector is a simple PN photodiode. The dynamic adjustment is performed via the voltage applied to the filter. In addition to the dynamic tunability, a key characteristic of this structure is its bandwidth, which remains consistently below 9, 8.5, 8, and 11.5 nm for blue, green, yellow-orange, and red regions, respectively. Notably, the materials used in this structure have been selected to be compatible with CMOS technology. Another feature of this sensor is its 50 nm spectral shift for each specified spectrum, achieved with a 15-volt bias. Furthermore, this device presents minuscule crosstalk (below 5%) compared to other devices.