Enhancing mid-wavelength InAs/GaSb type II superlattice infrared detector with monolithically integrated metalens

Mid-wavelength infrared (MWIR) detectors offer significant potential for applications in gas sensing, molecular spectroscopy, and remote sensing. Recently, there has been a trend towards the integration, multifunctionality, lightweight design, miniaturization, and power consumption reduction for MWIR detectors. To this end, various strategies have been explored, including the introduction of new materials, such as InAsSb-based materials or two-dimensional materials. Beyond material innovation, here we monolithically integrated a metalens onto the backside of an InAs/GaSb type-II superlattice (T2SL) detector. The detector with metalens achieves a 6-fold enhancement in responsivity with a detectivity of 3.0×10⁹ cmHz/W at 300 K. The signal-to-noise ratio of the detector with metalens is improved by an average of 8.2 dB over the temperature range of 77 K to 300 K. This design represents a promising strategy for achieving high-operating-temperature MWIR detectors, facilitating the realization of miniaturization and lightweight IR detection system.