Photonic-Enabled Real-time Spectrogram Analysis of sub-Nanosecond Microwave Events over a 40-GHz Instantaneous Bandwidth

We demonstrate an optical method based on an electro-optic time lens for real-time and gapless time-frequency analysis of microwave signals, with analysis rates up to 1.56 billion Fourier transforms per second, operation bandwidth spanning up to ~40 GHz, and a frequency resolution <1.56 GHz. The genuine gapless operation is thoroughly investigated by showing the successful detection of events as short as 160 ps, regardless of their time of arrival. The short time resolution makes this method ideally suited for the recovery of ultrafast frequency hop signals.