11:45 AM - 12:00 PM
▲ [5a-C14-8] Intensity fluctuation reduction in multi-wavelength visible sub-nanosecond optical pulses based on the pulsed operation of semiconductor-laser optical amplifier
Keywords:semiconductor optical amplifier, stimulated Raman scattering, intensity fluctuation
The pulsed-mode stimulated emission depletion (STED) microscopy is attracting much attention to realize efficient super-resolution bio-imaging. In our previous report, we have demonstrated a sub-nanosecond multi-wavelength STED optical pulse source ranging from 546-nm to 620-nm based on gain-switched semiconductor optical amplifier (GS-SOA) method incorporating multistage amplification, second harmonic generation (SHG) and stimulated Raman scattering (SRS). The developed method successfully produced multi-wavelength optical pulses having a maximal peak power of 20-W, which value is nearly two orders of magnitude higher than that for optical pulses directly generated from a commercially -available red laser diode (LD). However, in the previous experimental work, we have observed quite large intensity fluctuations in the SRS optical pulse temporal waveforms. Since we are using multi-stage nonlinear wavelength conversion process to obtain higher-order SRS optical pulses, it is reasonable to consider that the origin of the above fluctuations is the intensity fluctuation in fundamental excitation optical pulses. In the present report, we indicate that this understanding is correct, based on an experimental study.