Dpc 230 photon correlator

The fs pulsed laser (PHAROS PH1-10W, LIGHT CONVERSION; repetition rate: 1 MHz; pulse width: 200 fs) beam was introduced into a commercial inverted microscope (IX83, Olympus, Japan) as the excitation light. After being reflected by the dichroic mirror and passing through the objective (PLN20X, Olympus), the laser beam excited the sample. Based on a turnover mirror, emitted fluorescence signals passing through the dichroic mirror and filters were either delivered to a spectrometer (Andor, 193i + iXon DU-897U) or detected by an avalanche photodiode (τ-SPAD, PICOQUANT). The computer with an integrated TCSPC module system (DPC-230 Photon Correlator, Becker & Hickl GmbH) was used to measure the fluorescence lifetime of the sample based on the synchronous signals output by the fs laser and electrical signals from the τ-SPAD. The dependence of the ASF intensity of ICG in DMSO on the intensity of 915 nm fs pulsed laser excitation was derived from ICG’s fluorescence spectra excited at different powers.

The anti-Stokes fluorescence lifetime was measured via a time-correlated single-photon counting (TCSPC) system. A 980 nm femtosecond pulsed laser beam was introduced into an inverted microscope. The inside optical path was similar to Section 2.5. Finally, the anti-Stokes fluorescence signals were extracted and detected by an avalanche photodiode (τ-SPAD, PICOQUANT, Germany). The computer with an integrated TCSPC module (DPC-230 Photon Correlator, Becker & Hickl GmbH, Berlin, Germany) was used to record the fluorescence lifetime of samples based on the synchronous signals output by the femtosecond laser and electrical signals from the τ-SPAD. The fluorescence lifetime is equal to the time when the fluorescence intensity decreases from the peak to one of 1/e (e is the base of the natural logarithm).