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2025

Light | On-chip photoelectric detection system promotes the integrated application of light and intelligence

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Introduction

In today's digital age, optical communication and artificial vision technologies are developing at an unprecedented rate, driving transformation in numerous fields ranging from communication and medical care to security monitoring and autonomous driving. However, the limitations of traditional polarization light detection technologies, such as their large size, complex manufacturing, and high cost, severely restrict their further development.

Recently,Researcher Li Shaojue and Researcher Li Dabing from the Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, and their collaboratorshave made a breakthrough in this field. The team proposed an innovative method that transcends the constraints of material anisotropy, successfully developing a high-performance on-chip polarization-sensitive detection system based on all two-dimensional materials. In the infrared band, the anisotropic photocurrent ratio exceeds 60, reaching the level of current practical applications, and demonstrating its enormous application potential in optical communication and artificial vision. This provides a highly promising pathway for the long-sought miniaturized, high-performance, and multifunctional optoelectronic systems.

The relevant results are published under the title "Versatile on-chip polarization-sensitive detection system for optical communication and artificial vision" inLight: Science & ApplicationsThe first author of the paper isLiu Zhilin, a doctoral candidate at the Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of SciencesThe corresponding author isResearcher Li Shaojue from the Changchun Institute of Optics, Fine Mechanics and Physics。

Polarization, as an important attribute of light, can provide an additional dimension of information for optical signals, thereby enhancing imaging contrast and information transmission efficiency. Therefore, polarization-sensitive technology plays a crucial role in optical communication, spectroscopy, remote polarization imaging, and artificial vision. However, traditional polarization light detection systems rely on the combination of polarization optical elements and traditional photodetectors (such as Figure 1a). This combination is not only bulky but also complex and expensive to manufacture, making it difficult to meet the needs of modern miniaturized, high-performance optoelectronic systems.

In recent years, two-dimensional materials have shown great potential in addressing the above limitations due to their excellent optoelectronic and physical properties. In particular, two-dimensional materials with low-symmetry crystal structures, such as BP, ReS₂，PdSe₂，etc., have opened up new avenues for the development of on-chip polarization-sensitive photodetection (such asFigure 1b (i-ii)). However, these low-symmetry two-dimensional materials are limited in variety, and their anisotropy ratios (typically below 10) and responsivity still cannot meet the needs of practical applications. In addition, many isotropic two-dimensional materials with excellent light absorption are limited in their application to polarization detection. Although plasmonic nanostructures can enhance light-matter interaction through localized field enhancement and resonance absorption, nanostructures of fixed size only resonate at specific wavelengths. As the operating wavelength range expands, the difficulty of processing metal nanostructures increases gradually (such asFigure 1b (iii)), thus limiting their application development.

Figure 1: a. Traditional polarization detection technology; b. Overview and limitations of existing polarization light detectors based on two-dimensional materials; c. Schematic diagram and application demonstration of the polarization detection system

To overcome these limitations, the research team designed and constructed a polarization detection system based on all two-dimensional materials, introducing and enhancing the polarization-sensitive characteristics of isotropic two-dimensional materials. By integrating a photodetector based on WSe₂with a field-effect transistor based on MoS₂，high-performance broadband polarization detection is achieved (such asFigure 1c). The research team used metal electrode-induced hot electron injection to generate a polarization-dependent localized electric field at the electrode edge.Figure 2a-bshows that in the infrared band, the localized electric field exhibits obvious polarization dependence: it is strongest when the polarization direction of the incident light is perpendicular to the electrode edge and minimum when the polarization direction is parallel to the electrode edge. Given this, the team designed a metal-semiconductor Schottky interface as a hot electron capture receptor and used polarization-insensitive WSe₂as the channel material to fabricate a Schottky photodetector, thus eliminating the influence of the channel material itself on polarization absorption.Figure 2cshows that the device exhibits a significant polarization-dependent photoresponse in the near-infrared band. The anisotropic photocurrent ratio of the device reaches approximately 2 and 1.5 at wavelengths of 1064 nm and 980 nm, respectively. This design breaks the long-term dependence of on-chip polarization detectors on low-symmetry materials, but it is worth noting that only a relatively low anisotropy ratio is obtained in the device compared to the difference in the localized electric field, which is difficult to meet practical application requirements.

Figure 2: Design and characterization of polarization-sensitive photodetector based on WSe₂Therefore, to further improve device performance, the researchers constructed an on-chip integrated amplification system, integrating a MoS-based field-effect transistor with a WSe

polarization photodetector. The WSe₂Schottky detector serves as the photosensitive unit, and the MoS₂transistor serves as the amplification unit and output port. With changes in the input light state (on/off state, different polarization states), the gate voltage of the transistor changes, causing the transistor to switch between the on/off states, and the output current shows an order-of-magnitude change (such as₂Figure 3a-c₂). Under 1064 nm illumination, the system uses WSe图3a-c）。该系统在1064 nm的光照下，将WSe₂The anisotropic photocurrent ratio of the Schottky detector was increased to over 60, far exceeding that of polarization photodetectors in the same material system (such asFigure 3d-f). The system also exhibits high photosensitivity, with on/off ratios of 4.4 × 10³and 5.7 × 10⁵。

Figure 3: Polarization detection performance of the integrated system

As a demonstration,Figure 4a-bshows the application of this system in polarization-modulated optical communication, achieving perfect signal reproduction. In addition, the device, as a single-pixel imaging device, powerfully demonstrates the potential of this device in the field of linear polarization photodetection and achieves over 99% image recognition accuracy through an artificial neural network (such asFigure 4C-G). These results indicate the enormous application potential of this system in secure optical communication, hyperspectral imaging, and artificial vision.

Figure 4: Proof-of-concept applications of the polarization detection system for infrared polarization communication, polarization imaging, and recognition

Summary and Outlook

This research successfully developed a high-performance on-chip polarization detection system based on all two-dimensional materials, achieving a high anisotropy ratio, high responsivity, and excellent photosensitivity. By utilizing the hot electron injection mechanism induced by the plasmon resonance of the metal electrode, the research team broke through the traditional on-chip polarization detector's dependence on the inherent anisotropy of the material, giving WSe₂Schottky photodetector polarization-sensitive characteristics, realizing a transition from nothing to something. Furthermore, by integrating MoS₂transistors as amplification units, the system performance has achieved a leap from low to high. It is worth noting that this integration scheme is simple and versatile, applicable to various materials from isotropic to anisotropic, greatly expanding its applicability in different application scenarios.In addition, by optimizing interface states and surface modification, the Schottky barrier formed between the metal and the two-dimensional material can be further modulated, thereby improving the hot electron injection efficiency. At the same time, the resonance characteristics (including intensity and bandwidth) of the metal plasmon can be flexibly tuned by selecting different metals to further optimize system performance.

In summary, this research not only provides a new design paradigm for future polarization photodetectors but also shows great development potential in the field of chip-level optoelectronic applications.

Paper Information

Liu, Z., Liu, M., Qi, L., et al. A multifunctional on-chip polarization-sensitive detection system for optical communication and artificial vision. Light Science Applications 14，68 (2025).

https://doi.org/10.1038/s41377-025-01744-x