An optics-free computational spectrometer using a broadband and tunable dynamic detector

TL;DR

This paper introduces an innovative, optics-free computational spectrometer that uses a broadband, tunable detector to achieve high-resolution spectral measurements and time-of-flight capabilities without traditional optical components.

Contribution

It presents a novel single-detector spectrometer design that maps quantum efficiency into an inverse problem, enabling broadband operation and multifunctional spectral and time measurements.

Findings

Spectral range from 660 to 1900 nm achieved.

Spectral resolution of 6 nm at telecom wavelengths.

Demonstrated a spectral LiDAR with 8 channels.

Abstract

Optical spectrometers are the central instruments for exploring the interaction between light and matter. The current pursuit of the field is to design a spectrometer without the need for wavelength multiplexing optics to effectively reduce the complexity and physical size of the hardware. Based on computational spectroscopic results and combining a broadband-responsive dynamic detector, we successfully demonstrate an optics-free single-detector spectrometer that maps the tunable quantum efficiency of a superconducting nanowire into an ill-conditioned matrix to build a solvable inverse mathematical equation. Such a spectrometer can realize a broadband spectral responsivity ranging from 660 to 1900 nm. The spectral resolution at the telecom is 6 nm, exceeding the energy resolving capacity of existing infrared single-photon detectors. Meanwhile, benefiting from the optics-free setup, precise time-of-flight measurements can be simultaneously achieved. We have demonstrated a spectral LiDAR with 8 spectral channels. This work provides a concise method for building multifunctional spectrometers and paves the way for applying superconducting nanowire detectors in spectroscopy.