Event 

Title:
Seminar at the Accelerator - Fabrication of optical elements using keV and MeV energy ion beams
When:
24.11.2010 - 24.11.2010
Where:
CMAM - Madrid
Category:
Informal seminars at the Accelerator

Description

Speaker: István Bányász, Department of Crystal Physics, Research Institute for Solid State Physics and Optics Hungarian Academy of Sciences Budapest (Hungary)

Activities in the field of fabrication of optical elements using ion beams, performed at the KFKI Campus in Budapest, Hungary during the last 15 years will be presented. Ion implantation or irradiation proved to be a universal technique for producing waveguides and other optical elements in most optical materials. The first series of experiments aimed at the fabrication of efficient and environmentally stable transmission phase optical gratings glass via implantation of helium and nitrogen ions of energies in the 500 keV–1.6 MeV range, through photoresist masks. Phase profiles of the gratings were measured via interference and phase contrast microscopy and scanning electron microscopy. Quasi-sinusoidal profiles were obtained for the finest gratings. The highest diffraction efficiencies were around 20%. The goal of the second series of experiments was to design and fabricate active and passive channel and slab waveguides in Er-doped tellurite glasses and other (crystalline) materials. Erbium-doped tellurite glasses are of great interest for the fabrication of active integrated circuits because of their unique properties in terms of bandwidth and rare earth solubility. Fabrication of multimode channel waveguides in a sodium-tungsten-tellurite glass is demonstrated using a high-energy ion beam irradiation technique. Nitrogen ions with dose of 1.0- 1016 ions/cm2 and 1.5 MeV energy were used for this aim. Waveguiding effect was investigated using the end-fire coupling technique. Then attempts were made to optimise parameters of waveguide fabrication in the Er: tellurite glass via implantation of MeV energy N+ ions in a wide range of implanted doses. Besides of glasses, slab optical waveguides were designed and fabricated in CaF2, Bi4Ge3O12 and Bi12GeO20 crystals, also using MeV energy N+ ions. Waveguides were characterised using UV/VIS and NIR absorption spectroscopy, spectroscopic ellipsometry and m-line spectroscopy. Part of the implanted samples was annealed to improve waveguide properties. First working slab waveguides were fabricated in CaF2 crystals using implantation of MeV-energy medium-mass ions. Increasing energy of the implanted N+ ions to 3.5 MeV resulted in improved waveguide operation extended to λ = 1550 nm both in the Er: Te glass and eulytine type (Bi4Ge3O12) BGO crystals so far. Double-energy implantations to produce thicker barriers in the slab waveguides in the Er: Te glass are under way. In the third series of experiments low-energy ion implantation (Ar+ of 50 keV and N+ of 20 keV) is used to produce quasi-sinusoidal refractive index profile throughout the depth of thin (110 nm) layers of CVD grown SiO2 layers. A stack of 10 – 20 such layers then could act as an efficient Bragg grating.

[References]: I. Bányász, M. Fried, Cs. Dücső and Z.Vértesy, "Recording of transmission phase gratings in glass by ion implantation", Applied Physics Letters , 79, 3755-3757, (2001) S. Berneschi, G. Nunzi Conti, I. Bányász, A. Watterich, N. Q. Khanh, M. Fried, F. Pászti, M. Brenci, S. Pelli, G. C. Righini “Ion beam irradiated channel waveguides in Er3+-doped tellurite glass”, Applied Physics Letters, 90, 121136, (2007)

Venue

CMAM
Venue:
CMAM   -   Website
Street:
Faraday 3, Campus de Cantoblanco
ZIP:
28049
City:
Madrid
Country:
Country: es

Description

The seminar takes place at the meeting room of the CMAM