Femtosecond laser and swift-ion damage in lithium niobate: A comparative analysis
- Centro de Microanalisis de Materiales (CMAM), UAM, 28049 Madrid (Spain)
- Instituto de Optica 'Daza de Valdes', CSIC, C/Serrano 121, 28006 Madrid (Spain)
- Departamento de Fisica de Materiales, UAM, 28049 Madrid (Spain)
Relevant damage features associated with femtosecond pulse laser and swift-ion irradiations on LiNbO{sub 3} crystals are comparatively discussed. Experiments described in this paper include irradiations with repetitive femtosecond-laser pulses (800 nm, 130 fs) and irradiation with O, F, Si, and Cl ions at energies in the range of 0.2-1 MeV/amu where electronic stopping power is dominant. Data are semiquantitatively discussed by using a two-step phenomenological scheme. The first step corresponds to massive electronic excitation either by photons (primarily three-photon absorption) or ions (via ion-electron collisions) leading to a dense electron-hole plasma. The second step involves the relaxation of the stored excitation energy causing bond breaking and defect generation. It is described at a phenomenological level within a unified thermal spike scheme previously developed to account for damage by swift ions. A key common feature for the two irradiation sources is a well-defined intrinsic threshold in the deposited energy density U{sub th} required to initiate observable damage in a pristine crystal: U{sub th}{approx_equal}1.3x10{sup 4}-2x10{sup 4} J/cm{sup 3} for amorphization in the case of ions and U{sub th}{approx_equal}7x10{sup 4} J/cm{sup 3} for ablation in the case of laser pulses. The morphology of the heavily damaged regions (ion-induced tracks and laser-induced craters) generated above threshold and its evolution with the deposited energy are also comparatively discussed. The data show that damage in both types of experiments is cumulative and increases on successive irradiations. As a consequence, a certain incubation energy density has to be delivered either by the ions or laser photons in order to start observable damage under subthreshold conditions. The parallelism between the effects of laser pulses and ion impacts is well appreciated when they are described in terms of the ratio between the deposited energy density and the corresponding threshold value.
- OSTI ID:
- 21137242
- Journal Information:
- Journal of Applied Physics, Vol. 103, Issue 9; Other Information: DOI: 10.1063/1.2912494; (c) 2008 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GENERAL PHYSICS
ABLATION
AMORPHOUS STATE
CHLORINE IONS
ELECTRON-ION COLLISIONS
ENERGY DENSITY
FLUORINE IONS
ION BEAMS
IRRADIATION
LASERS
LITHIUM COMPOUNDS
MORPHOLOGY
MULTI-PHOTON PROCESSES
NIOBATES
OXYGEN IONS
PARTICLE TRACKS
PULSES
SILICON IONS
SOLID-STATE PLASMA
STOPPING POWER
THERMAL SPIKES