Ultraviolet-induced transient absorption in potassium dihydrogen phosphate and its influence on frequency conversion
- Lawrence Livermore National Laboratory, University of California, P.O. Box 808, Livermore, California 94551 (United States)
The optical properties of an ultraviolet (266-nm) -induced transient absorption in normal and deuterated potassium dihydrogen phosphate crystals are discussed. Our main contribution has been to analyze this effect quantitatively, assess its effect on ultraviolet (UV) frequency-conversion applications, and examine sample variability. As observed previously [Chem. Phys. Lett. [bold 207], 540 (1993)], the transient absorption is broad ([similar to] 200--700 nm) and is suggested to arise from an induced defect state resulting from the promotion of an electron into the conduction band by two-photon absorption. At room temperature we find that the defect absorption decays over a wide variety of time scales, ranging from fractions of a second to several days, depending on the particular sample under study. The decay time does not appear to be correlated with deuteration or chemical impurities. The temperature-dependent decay rate has an Arrhenius behavior with a single activation energy of 0.51 [plus minus] 0.04 eV for all samples studied, and the decay rate appears to be mediated by a diffusional process as previously postulated. We determined the defect absorption cross section at its spectral peak to be 6 [plus minus] 3 [times] 10[sup [minus]18] cm[sup 2]. Based on these and other measurements, we have numerically modeled previously published experimental data on fourth-harmonic frequency conversion of a Nd:YLF laser and found good agreement when the effects of transient absorption are included.
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 7042367
- Journal Information:
- Journal of the Optical Society of America, Part B: Optical Physics; (United States), Vol. 11:5; ISSN 0740-3224
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GENERAL PHYSICS
74 ATOMIC AND MOLECULAR PHYSICS
CRYSTALS
NONLINEAR OPTICS
POTASSIUM PHOSPHATES
FREQUENCY CONVERTERS
ABSORPTION SPECTRA
CROSS SECTIONS
CRYSTAL DEFECTS
FREQUENCY MODULATION
ULTRAVIOLET RADIATION
ALKALI METAL COMPOUNDS
CRYSTAL STRUCTURE
ELECTROMAGNETIC RADIATION
MODULATION
OPTICS
OXYGEN COMPOUNDS
PHOSPHATES
PHOSPHORUS COMPOUNDS
POTASSIUM COMPOUNDS
RADIATIONS
SPECTRA
661300* - Other Aspects of Physical Science- (1992-)
664200 - Spectra of Atoms & Molecules & their Interactions with Photons- (1992-)