SPI-based FMCW LIDAR: experimental demonstration of spatial decoupling of overlapping beat-note spectral contributions

Single-pixel imaging provides a promising alternative to conventional scanning systems and detector arrays in light detection and ranging (LIDAR). Here, we present an experimental proof-of-concept demonstration of single-pixel imaging applied to frequency-modulated continuous-wave LIDAR. We demonstrate simultaneous ranging and imaging of multiple objects, even when the frequency response contains only a single unresolved peak. This capability is enabled by reconstructing spatial information independently across spectral components, effectively decoupling spatial recovery from frequency resolution. As a result, closely spaced objects remain distinguishable despite overlapping spectral responses, demonstrating the potential to improve object separability without increasing the modulation bandwidth. The proposed approach is particularly attractive in hardware-constrained scenarios, including low-SNR conditions and cost-sensitive LIDAR implementations.