Beyond the wave: Rethinking spectrometer design through light's dual nature
Comprehensive review details how shifting from wave-based to particle-based designs overcomes century-old size and performance limits.
image: A timeline illustrating the historical progression of spectrometer technology, from Newton's prism-based dispersion (wave paradigm) to modern quantum dot and perovskite-based devices (particle paradigm).
Credit: Nano Research, Tsinghua University Press
Light’s spectrum carries the unique “fingerprints” of matter, making spectrometers indispensable tools across science and technology—from materials analysis to biomedical sensing. For centuries, spectrometers have been designed around light’s wave nature, using refraction, diffraction, and interference to separate light into its constituent wavelengths. This wave-based paradigm, while precise, inherently couples performance with physical size: achieving higher resolution or broader spectral range requires larger optical paths, limiting miniaturization.
Prof. Jie Bao in the Department of Electronic Engineering at Tsinghua University in Beijing, China, led a team that challenged this paradigm by embracing light’s dual nature. “The wave-particle duality of light isn’t just a theoretical concept—it’s a design opportunity,” said Bao. Building on this perspective, the newly published review by Bao’s group systematically revisits this design logic from the fundamental viewpoint of light’s dual nature. This review synthesizes past developments into a coherent framework that distinguishes wave-based and particle-based spectrometers, highlighting their principles, implementations, and performance.
Within this framework, wave-based spectrometers—including prism, grating, and Fourier transform systems—achieve high accuracy but struggle with size limitations. For example, grating spectrometers require precise optical paths to maintain resolution, while Fourier transform spectrometers face a direct trade-off between resolution and device size.
In contrast, particle-based spectrometers—first demonstrated by Bao et al. using quantum dots (Nature 2015, 523, 67)—utilize photon-electron interactions like transmission, absorption, emission, and scattering. These systems encode spectral information through material interactions and reconstruct it via advanced algorithms, eliminating the need for large optical components. “A particle-based spectrometer can integrate over a million nanoscale encoders in a square-millimeter chip,” explained Bao. “This high integrability, combined with broadband photon absorption, enables both compact size and high performance.”
The review also extends the discussion to spectral imaging, outlining three core principles for integrating spectrometers with imaging technology. By applying wave- or particle-based mechanisms, spectral imagers can now balance spatial and spectral resolution while reducing system complexity.
Looking forward, the authors envision hybrid spectrometers that combine wave-based precision with particle-based compactness. “Integrating resonant structures with tunable absorbers could create narrowband detectors that leverage both interference and absorption,” noted Bao. The authors also briefly analyze quantum-enhanced designs, where entangled photon pairs or squeezed states could push spectral detection beyond classical noise limits.
Overall, this review provides a comprehensive roadmap for future spectrometer development. “We believe this review offers valuable insights into the field and could inspire researchers across diverse areas—such as materials science, nanotechnology, physics, and optics—to collaborate, innovate, and contribute to the design and development of miniaturized spectrometers. Such efforts may further accelerate their integration into modern applications, including consumer electronics, big data analytics, and AI-enhanced machine vision, ultimately benefiting a broad range of industries,” said Bao.
Other contributors include Ding Zhao, Chensheng Dai, Yuxuan Zheng, Xin Jiang, and Jinhua Yin from the Department of Electronic Engineering at Tsinghua University in Beijing, China. This work was supported in part by QuantaEye (Beijing) Technologies Co., Ltd.
About Nano Research
Nano Research is a peer-reviewed, open access, international and interdisciplinary research journal, sponsored by Tsinghua University and the Chinese Chemical Society, published by Tsinghua University Press on the platform SciOpen. It publishes original high-quality research and significant review articles on all aspects of nanoscience and nanotechnology, ranging from basic aspects of the science of nanoscale materials to practical applications of such materials. After 18 years of development, it has become one of the most influential academic journals in the nano field. Nano Research has published more than 1,000 papers every year from 2022, with its cumulative count surpassing 7,000 articles. In 2024 InCites Journal Citation Reports, its 2024 IF is 9.0 (8.7, 5 years), and it continues to be the Q1 area among the four subject classifications. Nano Research Award, established by Nano Research together with TUP and Springer Nature in 2013, and Nano Research Young Innovators (NR45) Awards, established by Nano Research in 2018, have become international academic awards with global influence.