Integrated near-infrared spectral sensing

Abstract

Spectral sensing is increasingly used in applications ranging from industrial process monitoring to agriculture. Sensing is usually performed by measuring reflected or transmitted light with a spectrometer and processing the resulting spectra. However, realizing compact and mass-manufacturable spectrometers is a major challenge, particularly in the infrared spectral region where chemical information is most prominent. Here we propose a different approach to spectral sensing which dramatically simplifies the requirements on the hardware and allows the monolithic integration of the sensors. We use an array of resonant-cavity-enhanced photodetectors, each featuring a distinct spectral response in the 850-1700 nm wavelength range. We show that prediction models can be built directly using the responses of the photodetectors, despite the presence of multiple broad peaks, releasing the need for spectral reconstruction. The large etendue and responsivity allow us to demonstrate the application of an integrated near-infrared spectral sensor in relevant problems, namely milk and plastic sensing. Our results open the way to spectral sensors with minimal size, cost and complexity for industrial and consumer applications.

Doping Compensation Enables High‐Detectivity Infrared Organic Photodiodes for Image Sensing

“…Infrared photodetectors and imagers have attracted broad attention due to their application potentials in 3D imaging for artificial intelligence, machine vision, health monitoring and biometric authentication. [1][2][3][4] However, infrared photodetectors typically suffer from a high dark current and a low detectivity at room temperature due to the increased thermal emission and high trap density. Given that large dynamic range and weak light detection are prerequisites in many imaging applications, the infrared photodetectors/imagers usually require active cooling to reduce thermal noise.…”

Deep Coding Patterns Design for Compressive Near-Infrared Spectral Classification

“…The proposed method consists in modeling the 3D-CASSI system as an optical layer. Considering the rearrange step expressed in (2), the forward sensing model can be treated as a fully-connected layer, i.e., each coding pattern is multiplied element-wise with each spectral signature, where the number of patterns is equivalent to the number of neurons as illustrated in the sensing stage of Fig. 2.…”

“…It provides three-dimensional (3D) images, called spectral data cube, which captures spatial information along the electromagnetic spectrum [1]. While substantial progress has been made in the visible spectral region, up to 1100 nm, the progress in integrating of near-infrared (NIR) spectrum has been limited due to the optical material costs [2]. The NIR part of the electromagnetic spectrum, particularly the region 1000-1700 nm, provides a lot of information to determine the quality and safety of agricultural and food products [3].…”

“…The NIR part of the electromagnetic spectrum, particularly the region 1000-1700 nm, provides a lot of information to determine the quality and safety of agricultural and food products [3]. Other fields of interest and research areas where NIR hyperspectral imaging is applied include pharmaceuticals [4], medical applications [5], archaeology [6], and paleontology [7] since it provides higher sensitivity than solutions in the visible spectrum [2].…”

High-Performance Waveguide-Integrated Ge/Si Avalanche Photodetector with Lateral Multiplication Region

“…Near-infrared photodetectors have been widely used in fiber communication [ 1 , 2 , 3 , 4 , 5 ], spectroscopy [ 6 , 7 ], and light detection and ranging (LIDAR) [ 8 , 9 ]. High-speed and high-sensitivity photodetectors are desirable to relax the power budget and improve the energy efficiency of fiber communication.…”