A microsized optical spectrometer based on an organic photodetector with an electrically tunable spectral response

Miniaturized optical spectrometers could be of use in portable and wearable applications. Such devices have typically been based on arrays of photodetectors that provide distinct spectral responses or use complex miniaturized dispersive optics. However, these approaches often result in large centimetre-sized systems. Here we report a microsized optical spectrometer that is based on an optical-spacer-integrated photomultiplication-type organic photodetector with a bias-tunable spectral response. The approach allows the computational reconstruction of an incident light spectrum from photocurrents measured under a set of different bias voltages. The device, which has a footprint of 0.0004 cm², is capable of broadband operation across the entire visible wavelength with a sub-5-nm resolution. To illustrate the capabilities of this approach, we fabricate an 8 × 8 spectroscopic sensor array that can be used for hyperspectral imaging.