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Title: Internal structure of the nanogratings generated inside bulk fused silica by ultrafast laser direct writing

The aim of the present work was to characterize the internal structure of nanogratings generated inside bulk fused silica by ultrafast laser processing and to study the influence of diluted hydrofluoric acid etching on their structure. The nanogratings were inscribed at a depth of 100 μm within fused silica wafers by a direct writing method, using 1030 nm radiation wavelength and the following processing parameters: E = 5 μJ, τ = 560 fs, f = 10 kHz, and v = 100 μm/s. The results achieved show that the laser-affected regions are elongated ellipsoids with a typical major diameter of about 30 μm and a minor diameter of about 6 μm. The nanogratings within these regions are composed of alternating nanoplanes of damaged and undamaged material, with an average periodicity of 351 ± 21 nm. The damaged nanoplanes contain nanopores randomly dispersed in a material containing a large density of defects. These nanopores present a roughly bimodal size distribution with average dimensions for each class of pores 65 ± 20 × 16 ± 8 × 69 ± 16 nm{sup 3} and 367 ± 239 × 16 ± 8 × 360 ± 194 nm{sup 3}, respectively. The number and size of the nanopores increases drastically when an hydrofluoric acid treatment is performed, leading to the coalescence of these voids into large planar discontinuities parallel to the nanoplanes. The preferential etching of the damaged material by the hydrofluoric acid solution, which is responsiblemore » for the pores growth and coalescence, confirms its high defect density.« less
Authors:
;  [1] ;  [2] ;  [1] ;  [2] ;  [3]
  1. ICEMS—Instituto de Ciência e Engenharia de Materiais e Superfícies, Avenida Rovisco Pais no 1, 1049-001 Lisbon (Portugal)
  2. (Portugal)
  3. Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), Cantoblanco, Madrid 28049 (Spain)
Publication Date:
OSTI Identifier:
22314533
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 116; Journal Issue: 5; Other Information: (c) 2014 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; COALESCENCE; DAMAGE; DEFECTS; DENSITY; DEPTH; DISTRIBUTION; ETCHING; HYDROFLUORIC ACID; KHZ RANGE; LASERS; MATHEMATICAL SOLUTIONS; NITROGEN 20; NITROGEN 21; PERIODICITY; PROCESSING; RANDOMNESS; SILICA; VOIDS; WAVELENGTHS