基于受激增益与自发衰减的激发-探测显微技术

Translated title of the contribution: Stimulated gain and spontaneous loss pump-probe microscopy

Bowei Ho, Yizhi Liang, Chelun Hsu, Subir Das, Fujen Kao

Research output: Contribution to journalArticlepeer-review

Abstract

In this work, the pump-probe microscope was used to study the stimulated gain and spontaneous loss phenomenon. A pulsed diode laser, λpu=635 nm as the pump (excitation) beam and a mode-locked Tisapphire laser, λpr=780 nm, as the probe (stimulation) beam were applied. For stimulated gain, the pump beam was modulated at a frequency, f1, and the probe beam was demodulated accordingly to extract the signal in the transmission direction with a photodiode as the detector (PDA 36A, Thorlabs). For spontaneous loss, the probe beam was modulated at frequency, f2, the spontaneous loss signal was then demodulated from the fluorescence detected in the reflection mode by a PMT. In all cases, a high performance lock-in amplifier (HF2LI, Zurich Instruments) was used. The output signal of the lock-in amplifier was then fed to the A/D channel of the scanning unit for image reconstruction. The scan rate was set at a frequency 500 Hz, to match the time constant (1.99 ms) of the lock-in amplifier. By demodulating fluorescence signal, the fluorescence lifetime and optical section images can be obtained with greatly reduced background, in which shot noise was attributed. Additionally, the signal-to-noise ratio was improve and penetration depth like multiphoton microscopy was enhanced, without expansive femtosecond lasers.

Translated title of the contributionStimulated gain and spontaneous loss pump-probe microscopy
Original languageChinese (Traditional)
Article number0606004
JournalHongwai yu Jiguang Gongcheng/Infrared and Laser Engineering
Volume47
Issue number6
DOIs
StatePublished - 25 Jun 2018

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