Near-Field and Complex-Field Time-Stretch Transform

The time-stretch dispersive Fourier transform enables high-throughput acquisition of optical spectra in single-shot measurements by performing an analog Fourier transform and stretching the signal to facilitate capture with high-speed electronics. The coherent time-stretch transform adds complex-field detection so that spectral amplitude and phase can be measured in the temporal near field, i.e., without a strict dispersion requirement. Full-field spectra are recovered via temporal interferometry on waveforms dispersed in the temporal near field. Real-time absorption spectra including both amplitude and phase information are acquired at 37 MHz.