Cascaded Optical Kerr Gate for Fluorescence Measurement With High Signal-to-Noise Ratio

Traditional optical Kerr gates (OKG) often suffer from leakage fluorescence background when sampling and measuring fluorescence spectra due to the limited extinction of the polarizers used in optical Kerr gates. In this letter, we propose a cascaded optical Kerr gate (COKG) for measuring fluorescence spectroscopy with a high signal-to-noise ratio by suppressing this leakage fluorescence background. Our proposed COKG consists of an optical Kerr gate with a fast-switching time at the front stage and an optical Kerr gate with a high transmission at the back stage. The experimental results show that the signal-to-noise ratio for the COKG can be improved by about two orders of magnitude compared to the single OKG.