A high-peak-power UV picosecond-pulse light source based on a gain-switched 1.55 microm laser diode and its application to time-resolved spectroscopy of blue-violet materials.

We generated sub-kilowatt peak-power and 6-ps duration 390-nm optical pulses via the fourth harmonic generation of amplified optical output from a gain-switched 1.55-microm laser diode. We obtained a power-conversion-efficiency of 12% from 1.55-microm to 390-nm light, and subsequently applied the ultraviolet pulses to time-resolved spectroscopy of blue-violet luminescent materials, including a Coumarine dye solution and nitride semiconductor materials using single-photon and two-photon excitation schemes.

Two-photon bioimaging utilizing supercontinuum light generated by a high-peak-power picosecond semiconductor laser source.

We developed a novel scheme for two-photon fluorescence bioimaging. We generated supercontinuum (SC) light at wavelengths of 600 to 1200 nm with 774-nm light pulses from a compact turn-key semiconductor laser picosecond light pulse source that we developed. The supercontinuum light was sliced at around 1030- and 920-nm wavelengths and was amplified to kW-peak-power level using laboratory-made low-nonlinear-effects optical fiber amplifiers. We successfully demonstrated two-photon fluorescence bioimaging of mouse brain neurons containing green fluorescent protein (GFP).

Two-photon bioimaging with picosecond optical pulses from a semiconductor laser.

Toward a practical light source for two-photon bioimaging, we have generated kilowatt peak power of 0.77 mum wavelength and 5 ps optical pulse via second-harmonic generation of the amplified output from a gain-switched 1.55 mum semiconductor laser. This compact scheme and stable optical-pulse-source has been successfully used for the two-photon fluorescence bioimaging of actin filaments in PtK2 cells.