Real-time all-optical overlapping time-lens array through nonlinear interference

The space–time duality is a foundational principle in modern optical signal processing, enabling temporal analogues of spatial imaging systems. Among the key components in such systems are time-lenses, whose versatility remains limited when arranged in arrays. Yet such configurations are essential for enabling high-resolution, gap-free optical spectral analysis and photonic waveform generation, among other demanding applications. In this work, we introduce an overlapping time-lens array (oTLA) that exploits nonlinear interference via both degenerate and non-degenerate four-wave mixing. This design breaks the strict trade-off between aperture length and repetition rate inherent in conventional approaches. As a result, the oTLA enables the simultaneous achievement of high time-bandwidth products—beyond several thousand—along with high repetition rate and complete and redundant temporal coverage of the input optical signal, ensuring truly gap-free operation. We showcase the capabilities of the oTLA with overlapping factors exceeding 4 and a real-time gap-free optical spectrum analysis scheme with an analysis bandwidth of 400 GHz. This proposal opens avenues for temporal imaging systems in applications demanding seamless processing, such as in ultrafast spectroscopy, high-speed telecommunications, quantum optics, and the full-field measurement of broadband optical signals.