UV Pump Research Articles

Light-induced defects in aluminum nitride ceramics

Aluminum nitride (AlN) ceramic samples exhibit a dramatic photo-darkening when exposed to UV radiation. In this paper, this phenomenon has been investigated utilizing photo-induced absorption measurements, where the transmission of a visible probe beam is monitored before and after exposure to a UV pump beam. Changes in the probe transmission as large 60% have been observed. The results of this study show that the center responsible for the photo-induced absorption process is an aluminum vacancy-oxygen impurity complex which resides in the AlN lattice. An energy level diagram is constructed which is consistent with these experimental findings.

Simple generation of 400–700 nm picosecond dye laser pulses with nanosecond laser pumping

New results in the experimental study of the spectro-temporal selection (STS) method to produce picosecond dye laser pulses are presented. Adjustability of the picosecond pulse wavelength, possibility of extension of the STS method to different dyes and to UV pump wavelength, stability of the output pulse duration and intensity, and the concentration effect on pulse duration, are reported for the first time. From these results, production of high power picosecond (50–100 ps) dye laser pulses spectrally adjustable between 400 and 700 nm is obtained with a standard nanosecond pump laser, in a compact and simple device.