Quantum-dot light-chip micro-spectrometer

Abstract

Micro-spectrometers have great potential in various fields such as medicine, agriculture, and aerospace. In this work, a quantum-dot (QD) light-chip micro-spectrometer is proposed in which QDs emit different wavelengths of light that are combined with a spectral reconstruction (SR) algorithm. The QD array itself can play the roles of both the light source and the wavelength division structure. The spectra of samples can be obtained by using this simple light source with a detector and algorithm, and the spectral resolution reaches 9.7 nm in the wavelength range from 580 nm to 720 nm. The area of the QD light chip is 4 × 7.5 mm2, which is 20 times smaller than the halogen light sources of commercial spectrometers. It does not need a wavelength division structure and greatly reduces the volume of the spectrometer. Such a micro-spectrometer can be used for material identification: in a demonstration, three kinds of transparent samples, real and fake leaves, and real and fake blood were classified with an accuracy of 100%. These results indicate that the spectrometer based on a QD light chip has broad application prospects.

Random broadband filters based on combination of metasurface and multilayer thin films for hyperspectral imaging

“…As shown in figure 4(a), the reconstructed spectrum is aligned closely with the ground truth. Subsequently, employing the Rayleigh criterion to assess the spectral resolution of the micro-spectrometer [19], we examined its capability to differentiate between bimodal spectral signals. A novel bimodal spectrum with intensity I, where I = I λ1 + I λ2 , is generated by simultaneously introducing two unimodal spectra with intensities I λ1 and I λ2 , each separated by 2 nm.…”

“…For the resonant narrowband filters, it is challenging to achieve high spectral resolution due to the limited number of spectral channels corresponding to the number of filters [13][14][15][16][17]. More efficient approaches utilize random broadband micro/nano filters, which could be achieved via quantum dot arrays [18,19], photonic crystal plate arrays [20,21], multilayer thin films filters [22][23][24], bandgap tunable nanowires [25,26] and metasurface arrays [27][28][29]. These alternatives encode the spectral information of incident light as a series of responses at different locations on detector.…”