TY - GEN
T1 - Interaction of short and intense light pulses with matter
T2 - Damage to VUV, EUV, and X-ray Optics
AU - Guizard, S.
AU - Geoffroy, G.
AU - Gaudin, J.
AU - De Grazia, M.
AU - Carré, B.
AU - Merdji, H.
AU - Belsky, A.
AU - Fedorov, N.
AU - Martin, P.
PY - 2007/11/19
Y1 - 2007/11/19
N2 - Light sources capable to deliver intense and ultrashort pulses in the VUV domain, based on free electron lasers or on the high order harmonic generation have appeared recently [1,2]. They bring the possibility to explore a new domain in the field of laser matter interaction. Such sources are available in the visible or near IR range -specially at 800 nm, thanks to Ti-Sa lasers - since more than ten years, and the interaction of femtosecond pulses with solids has been studied in great details. In this paper we will discuss how the knowledge which has been acquired in the visible domain can be used for the VUV studies. I will concentrate on the case of wide band gap dielectric materials (SiO 2, MgO, Al 2O 3), and on the intensity domain around breakdown and ablation threshold. This type of material is interesting not only because they are involved in numerous applications, but above all because their band gap (Eg) lying in the range 6 to 10 eV, a clear distinction can be made for what concern their interaction with visible (hvEg). We discuss here two important aspects that must taken into account to understand the energy balance of the interaction. The first is the energy distribution of photoexcited carriers, which are clearly different in the case of visible or VUV light. Photoemission spectroscopy demonstrate that the distribution highly depends upon the incident intensity in the visible and near IR, and can be "warmer" than the one observed by irradiation with VUV photon, despite their much larger energies. The second important parameter is the excitation density achieved during the excitation. Experiments carried out in the IR using the technique of time resolved interferometry allow to measure the density of electrons excited in the conduction band at intensities above and below the optical breakdown threshold. The results show that in the process of laser breakdown multiphoton excitation dominates the avalanche process for picosecond and subpicosecond pulses. The simulations performed to interpret these measurements can be used to predict the damaging mechanism of wide band gap dielectrics submitted to ultra intense VUV pulses.
AB - Light sources capable to deliver intense and ultrashort pulses in the VUV domain, based on free electron lasers or on the high order harmonic generation have appeared recently [1,2]. They bring the possibility to explore a new domain in the field of laser matter interaction. Such sources are available in the visible or near IR range -specially at 800 nm, thanks to Ti-Sa lasers - since more than ten years, and the interaction of femtosecond pulses with solids has been studied in great details. In this paper we will discuss how the knowledge which has been acquired in the visible domain can be used for the VUV studies. I will concentrate on the case of wide band gap dielectric materials (SiO 2, MgO, Al 2O 3), and on the intensity domain around breakdown and ablation threshold. This type of material is interesting not only because they are involved in numerous applications, but above all because their band gap (Eg) lying in the range 6 to 10 eV, a clear distinction can be made for what concern their interaction with visible (hvEg). We discuss here two important aspects that must taken into account to understand the energy balance of the interaction. The first is the energy distribution of photoexcited carriers, which are clearly different in the case of visible or VUV light. Photoemission spectroscopy demonstrate that the distribution highly depends upon the incident intensity in the visible and near IR, and can be "warmer" than the one observed by irradiation with VUV photon, despite their much larger energies. The second important parameter is the excitation density achieved during the excitation. Experiments carried out in the IR using the technique of time resolved interferometry allow to measure the density of electrons excited in the conduction band at intensities above and below the optical breakdown threshold. The results show that in the process of laser breakdown multiphoton excitation dominates the avalanche process for picosecond and subpicosecond pulses. The simulations performed to interpret these measurements can be used to predict the damaging mechanism of wide band gap dielectrics submitted to ultra intense VUV pulses.
KW - Densely excited matter
KW - Electronic excitation and relaxation mechanisms
KW - Femtosecond light pulse
KW - IR
KW - Laser induced breakdown
KW - VUV
U2 - 10.1117/12.723986
DO - 10.1117/12.723986
M3 - Conference contribution
AN - SCOPUS:36049036544
SN - 0819467146
SN - 9780819467140
T3 - Proceedings of SPIE - The International Society for Optical Engineering
BT - Damage to VUV, EUV, and X-ray Optics
Y2 - 18 April 2007 through 19 April 2007
ER -