Capturing ultra-broadband complex-fields of arbitrary duration using a real-time spectrogram

One of the most intuitive representations a waveform is achieved through time-frequency analysis, which depicts how frequency components wave evolve over time. Time-frequency representations, such as spectrogram, are well-known for allowing full-field characterization signal in terms amplitude and phase. However, present methods to capture spectrogram only suited either relatively slow (<GHz bandwidth) waveforms arbitrary duration or fast (>THz short duration. It remains very challenging representation broadband waves extending long durations, required many important fields science technology. Here, we introduce linear optics temporal imaging concept based on electro-optic time-lensing dispersive propagation map 2D 1D along domain. This technique enables ultra-broadband analysis without any gaps acquisition with no inherent limitation maximum The captured at unmatched processing rates, up 16 × 109 Fourier transforms per second (∼60 ps spectral frame), using single photodetector fully self-referenced manner. Under certain conditions, show this method single-shot optical spanning multiple THz. further showcased accurate phase recovery high-speed complex-modulated telecommunication signals direct intensity detection. will enable study physical phenomena unreachable date disruptive advancements communications, sensing, information processing.