Monolithic integration of metalens on III–V photodetectors for enhanced sensing

Short-wave infrared (SWIR) detectors hold significant application potential in fields, such as optical communications, low-light night vision, and LiDAR. In recent years, SWIR detectors have been advancing toward higher integration, enhanced sensitivity, miniaturization, and lower power consumption. Utilizing the precise control of optical wavefront phase and amplitude by metasurfaces enables efficient light focusing. This work proposes a scheme for the direct on-chip integration of a solid-immersion metalens with an InGaAs/InP PIN infrared detector. The integrated metalens-enhanced detector achieves a 2.4-fold improvement in responsivity compared to the detectors without metalens within the communication band and yields a specific detectivity of 2.37 × 1011 cm Hz1/2/W. This approach significantly enhances detector responsivity without introducing additional dark current or capacitance, thereby paving the way for the development of highly sensitive and miniaturized infrared detectors.