Mid‐Infrared Single‐Photon Sub‐Pixel Temporal Ghost Imaging

ABSTRACT Temporal ghost imaging (TGI) enables ultrafast temporal signal recovery using slow detectors, offering a promising route for high‐speed mid‐infrared (MIR) detection. However, conventional schemes remain limited in temporal resolution by the modulation bandwidth or pattern timescale, and are mostly confined to structured illumination. Here, we demonstrated a high‐resolution MIR single‐photon computational TGI system, which integrated nonlinear structured detection with sub‐pixel temporal shifting. A pre‐programmed near‐infrared pump serves as a temporally optical gate to drive sum‐frequency generation in a nonlinear crystal. Consequently, MIR waveforms at 3.4 were upconverted, and captured by a room‐temperature silicon detector. We realized sub‐pixel operation by fractional‐bin temporal stepping of the gate and multi‐shot fusion via pseudo‐inverse reconstruction. The sub‐pixel shifting strategy decouples the achievable resolution from modulation speed, enabling 40 ps temporal precision at a driving rate of only 3.125 Gbps. This performance surpasses both detector jitter and pattern‐rate limits, while maintaining single‐photon sensitivity. The presented paradigm establishes a versatile route for ultrafast MIR waveform reconstruction, opening new opportunities in high‐resolution infrared sensing and quantum photonics.