The coupling effect of simultaneous multi-wavelength irradiation on multilayer thin-films

Zhou, Ming; Shao, Jianda; Zhang, Fan; Ling, Xiulan; Li, Shuhong

doi:10.1016/j.optcom.2010.04.042

Cited by 5 publications

(1 citation statement)

References 22 publications

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“…Fortunately, researchers have done a lot of previous work about the single laser induced damages in optical films [5][6][7] and multiple lasers induced damages in other optical materials including KDP/DKDP [8][9][10][11] and Fused Silica [3,12,13]. As for the coupling effect about the multiple lasers induced damages in coatings, our group has done some pioneer works [14][15][16][17]. However, our preliminary studies are mainly concentrated on the damage morphologies and damage probabilities of coatings prepared by HfO 2 /SiO 2 when the 355 nm pulse fluence are three special values: lower LIDT, near LIDT and higher LIDT.…”

Section: Intorductionmentioning

confidence: 99%

Coupling effect of multi-wavelength lasers in damage performance of multilayer mirrors at 355 nm and 1064 nm

Yan¹,

Wei

et al. 2011

SPIE Proceedings

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Coupling effect between 355 nm laser and 1064 nm laser in damage initiation and morphology formation are investigated on two different coatings prepared with Hf/SiO 2 and HfO 2 /SiO 2 respectively. It was found that materials had little influence on the couple effect. When extra 1064 nm pulse energy is low, 355 nm laser induced damage thresholds of both coatings increase because of laser conditioning and then when 1064 nm pulse energy is high enough, 355 nm LIDTs decreased. Damage morphologies are also studied to explore the damage mechanism at respective wavelength.For the entirely different electric field distribution, 355 nm laser induced damages are mainly from nanometer-sized absorbers at upper interfaces while initiators for 1064 nm laser locate at substrate-coating interface or substrate subsurface. Under simultaneous illumination, the sensitive defects are still the precursors, but the damages are more catastrophic compared with damages induced by 355 nm laser only and they also show representative damage characteristics induced by single laser, namely 355 nm laser induced small pits and 1064 nm laser induced large delamination. Further studies also show that delamination area grows with the increase of pit numbers induced by 355 nm laser at fixed 1064 nm laser fluence. A possible mechanism was proposed to interpret observed delamination area growth phenomenon.Keywords: multi-wavelength laser, thin film beam splitter, laser induced damage, couple effect INTORDUCTIONIn high power laser systems, such as Laser MégaJoule in France and National Ignition Facility in US, beam separation system is a key part since that the third harmonics, which is used for Inertial Confinement Fusion, will mix with the fundamental frequency laser and the second harmonics after the frequency converting systems. Thin film beam splitters[1] are designed to reflect the useful part while transmit the residual lasers, and these coating have great advantages: 1) the reflective laser is perpendicular to the others so the laser can be arranged efficiently while the traditional wedged prism [2] can only separate the lasers with a small angle, 2) the coating preparation process is relatively simple compared with the focusing grating[3] manufacture. However, due to the low Laser Induced Damage Threshold (LIDT), coating was not applicable in high power laser systems. Nowadays, with the development of coating

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