Title :
Ultrafast induced absorption dynamics in flux-grown KTiOPO/sub 4/
Author :
Pasiskevicius, V. ; Ekvall, K. ; Clemens, R. ; Laurell, F.
Author_Institution :
Dept. of Phys., R. Inst. of Technol., Stockholm, Sweden
Abstract :
Summary form only given. KTiOPO/sub 4/ (KTP) is a ferroelectric nonlinear optical crystal with large second-order nonlinearities and it is attractive for fabrication of quasi-phasematched structures, suitable for frequency conversion applications throughout the visible to mid-infrared optical spectrum. However, experiments employing high-intensity visible light have revealed formation of color-centers in KTP, with broad absorption spectrum spanning from below 400 nm up to 650 nm and the relaxation time of the order of tens of minutes. The color-center formation has been attributed to the capture of free electrons and holes by the native defects (Ti/sup 4+/-Vo) and impurities (Fe/sup 3+/), respectively. We report on the femtosecond time-resolved transmission spectroscopy in KTP which revealed surprisingly large absorption increase over a broad spectral range in the visible, induced by the ultraviolet (UV) pump, and the full recovery of only 1.2 ps.
Keywords :
V-centres; colour centres; defect absorption spectra; ferroelectric materials; high-speed optical techniques; impurities; impurity absorption spectra; optical fabrication; optical frequency conversion; optical materials; optical phase matching; optical pumping; photochromism; potassium compounds; time resolved spectra; titanium compounds; visible spectra; 400 to 650 nm; KTiOPO/sub 4/; UV pump; broad absorption spectrum; broad spectral range; color-center formation; color-centers; fabrication; femtosecond time-resolved transmission spectroscopy; ferroelectric nonlinear optical crystal; flux-grown KTiOPO/sub 4/; free electrons capture; free holes capture; frequency conversion applications; high-intensity visible light; impurities; mid-infrared optical spectrum; native defects; quasi-phasematched structures; relaxation time; second-order nonlinearities; ultrafast induced absorption dynamics; ultraviolet pump; visible optical spectrum; Charge carrier processes; Electromagnetic wave absorption; Electron optics; Ferroelectric materials; Frequency conversion; Impurities; Nonlinear optics; Optical device fabrication; Optical pumping; Ultrafast optics;
Conference_Titel :
Lasers and Electro-Optics, 2001. CLEO '01. Technical Digest. Summaries of papers presented at the Conference on
Conference_Location :
Baltimore, MD, USA
Print_ISBN :
1-55752-662-1
DOI :
10.1109/CLEO.2001.947401
