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Title: Nanograting formation on metals in air with interfering femtosecond laser pulses

It is demonstrated that a homogeneous nanograting having the groove period much smaller than the laser wavelength (∼800 nm) can be fabricated on metals in air through ablation induced by interfering femtosecond laser pulses (100 fs at a repetition rate of 10 Hz). Morphological changes on stainless steel and Ti surfaces, observed with an increase in superimposed shots of the laser pulses at a low fluence, have shown that the nanograting is developed through bonding structure change at the interference fringes, plasmonic near-field ablation to create parallel grooves on the fringe, and subsequent excitation of surface plasmon polaritons to regulate the groove intervals at 1/3 or 1/4 of the fringe period over the whole irradiated area. Calculation for a model target having a thin oxide layer on the metal substrate reproduces well the observed groove periods and explains the mechanism for the nanograting formation.
Authors:
 [1] ;  [2] ;  [1] ;  [2] ;  [1]
  1. Laser Science Research Section, Institute of Advanced Energy, Kyoto University, Uji, Kyoto 611-0011 (Japan)
  2. (Japan)
Publication Date:
OSTI Identifier:
22489104
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 107; Journal Issue: 7; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ABLATION; AIR; EXCITATION; INTERFERENCE; IRRADIATION; LASERS; LAYERS; METALS; MORPHOLOGICAL CHANGES; NANOSTRUCTURES; OXIDES; POLARONS; PULSES; STAINLESS STEELS; SUBSTRATES; WAVELENGTHS