Femtosecond laser induced damage of pulse compression gratings. (1st December 2017)

• Record Type: Journal Article
• Authors: Kong, Fanyu; Huang, Haopeng; Wang, Leilei; Shao, Jianda; Jin, Yunxia; Xia, Zhilin; Chen, Junming; Li, Linxin
• Is Part Of: Optics & laser technology. Volume 97(2017)
• Page Start: 339
• Page End: 345
• Publication Date: 2017-12-01
• Subjects: Multilayer dielectric gratings -- Femtosecond pulse damage -- Diffraction gratings; Optics -- Periodicals; Lasers -- Periodicals; Electronic journals; 621.366
• DOI: 10.1016/j.optlastec.2017.07.021
• Languages: English
• ISSNs: 0030-3992

Abstract

Highlights: The damage picture of MMDG shows the weakness locates at HfO2 in grating structure. The weakness of ACG is considered in the interface of metal film and photoresist. The strong adhesive in the interface will improve damage resistance of ACG. Single SiO2 grating structure will improve damage resistance of MMDG. Abstract: Laser induced damage of Au-coated gratings (ACG) and metal multilayer dielectric gratings (MMDG) for pulse compression were measured using 800 ± 35 nm femto-laser with pulse width of 30.2 fs. The -1st order diffraction efficiency of the ACG is over 90% in wavelength range from 700 to 1000 nm. The MMDG has a 148 nm bandwidth (750–897 nm) with -1st order diffraction efficiency greater than 90%. The laser damage experiment on grating samples was performed in air for single-shot damage. The single-shot damage threshold of the ACG and MMDG was determined to be 0.32 ± 0.02 J/cm 2 and 0.31 ± 0.02 J/cm 2, respectively. The damage morphologies of the ACG revealed that the damage was attributed to the pinholes at the base of the grating pillars and the weak adhesion between metal layer and photoresist gratings layer. The damage feature combined with near field distribution of MMDG indicated that the damage was due to the nonlinear ionization process of the valence electrons in HfO2 film. According to analysis results, the laser damage resistance of the ACG can be enhanced through avoiding the appearance of pinholes and increasing adhesion between metal layer and photoresist layer. And for the MMDG, good performance of HfO2 film, low near field enhancement and single HfO2 grating structures may increase its laser damage resistance.