Waveguide structures in heavy metal oxide glass written with femtosecond laser pulses above the critical self-focusing threshold

• DOI: 10.1063/1.1888032
• Publication Date: 2005-03-15T03:32:01Z
• Authors: J. Siegel; J. M. Fernández-N...; A. García-Navarro; V. Diez-Blanco; O. Sanz; J. Solis; F. Vega; J Armengol
• Keywords: Self-focusing; Waveguide

We study the feasibility of femtosecond laser writing optical waveguides in bulk 35PbO∙35Bi2O3∙15Ga2O3∙15GeO2 glass, motivated by extended transparency interval heavy metal oxide glasses mid-infrared regime. Its large linear and nonlinear refractive indices cause critical self-focusing to occur even at low energies, leading filamentary propagation material damage. However, vicinity laser-damaged region shows a considerable increase index, which we attribute collateral, stress-induced densification due high pressures generated focal region. These regions increased index are strongly birefringent sufficiently support efficient light transversally written structures. Optical with ⩾10−3 minimal mode ellipticity have been obtained.