Megahertz detection of spectroscopic polarization by a time-encoded supercontinuum vector beam

We demonstrated a 40-MHz detection of spectroscopic polarization by a supercontinuum vector beam with a wavelength-dependent polarization state. To achieve the high-repetition-rate measurement, we detected the rotation angle of polarization and the spectrum by measuring the temporal waveform using a photodetector after expanding the pulse duration of the supercontinuum vector beam. The spectrum of the supercontinuum vector beam was measured using a spectrometer. We compared it with the temporal waveforms, confirming a good agreement of spectra between the conventional spectrometer and the temporal waveforms. The detection method is useful for many applications requiring high-repetition-rate spectroscopic-polarization measurements, such as the defect inspection of thin optical materials.