We report continuous wave 1.06 m laser operation in an optical waveguide fabricated in a Nd:YAG ceramic by femtosecond laser writing. Single mode and stable laser oscillation have been achieved by using the natural Fresnel reflection for optical feedback. Output laser power in excess of 80 mW and a laser slope efficiency of 60% have been demonstrated. © 2008 American Institute of Physics. ͓DOI: 10.1063/1.2890073͔Femtosecond direct laser writing ͑DLW͒ of transparent materials is attracting much attention because of the unique possibility of three-dimensionally modifying, at the micrometric and submicrometric scale, the optical properties of the irradiated media. This technique has been already proved to be a powerful and flexible tool for the fabrication of a great variety of optoelectronic components such as photonic crystals, diffraction gratings, and optical memories.1-3 When femtosecond pulses are focused inside a dielectric material, a permanent change in the refractive index is produced, in such a way that optical waveguides could be generated. This possibility has been already demonstrated in a great variety of glasses and crystals. [4][5][6] The further use of the DLW technique for the fabrication of low-loss channel waveguides in laser materials could be highly advantageous with respect to other fabrication approaches, and could also lead to technology breakthroughs in the development of threedimensionally integrated optical circuits.Among the different solid state laser media, neodymium doped yttrium aluminum garnet ͑YAG͒ transparent ceramics are nowadays attracting a great interest because of its advantages over the traditionally used Nd:YAG crystals. These advantages are the lower manufacturing costs, the possibility of high neodymium contents without any decrease in the optical quality of the gain medium, and also the possibility of direct composite fabrication.7 As a matter of fact, the laser performance of Nd:YAG ceramics has been found to be equal or even superior to that corresponding to Nd:YAG crystals. 8 Recently, authors reported on the fabrication of near surface channel waveguides in Nd:YAG ceramics.9 Nevertheless, up to date no attempt has been made, to the best of our knowledge, for the fabrication of buried channel waveguides in Nd:YAG ceramics by femtosecond DLW. The possible application of such waveguides as reliable and integrated laser sources is, therefore, still unexplored.In this letter, we report on the fabrication of buried channel waveguide lasers in Nd:YAG ceramics by using a two line confinement approach. Light confinement has been achieved between two parallel tracks due to filamentation of the femtosecond laser pulses. The possible influence of the waveguide fabrication process on the spectroscopic properties of the neodymium ions has been investigated by timeresolved confocal microscopy. We have also demonstrated highly efficient and stable laser oscillation based on the femtosecond written waveguide.The Nd:YAG ceramic sample used in this work was provided by Baikowski Ltd....
Nanostructuring hard optical crystals has so far been exclusively feasible at their surface, as stress induced crack formation and propagation has rendered high precision volume processes ineffective. We show that the inner chemical etching reactivity of a crystal can be enhanced at the nanoscale by more than five orders of magnitude by means of direct laser writing.The process allows to produce cm-scale arbitrary three-dimensional nanostructures with 100 nm feature sizes inside large crystals in absence of brittle fracture. To showcase the unique potential of the technique, we fabricate photonic structures such as sub-wavelength diffraction gratings and nanostructured optical waveguides capable of sustaining sub-wavelength propagating modes
We report the fabrication of single mode buried channel waveguides for the whole mid-infrared transparency range of chalcogenide sulphide glasses (λ ≤ 11 µm), by means of direct laser writing. We have explored the potential of this technology by fabricating a prototype three-dimensional three-beam combiner for future application in stellar interferometry, which delivers a monochromatic interference visibility of 99.89% at 10.6 µm, and an ultrahigh bandwidth (3-11 µm) interference visibility of 21.3%. These results demonstrate that it is possible to harness the whole transparency range offered by chalcogenide glasses on a single on-chip instrument by means of direct laser writing, a finding that may be of key significance in future technologies such as astrophotonics and biochemical sensing. . An essential step in order to unleash all of this potential science is to develop integrated optical platforms capable of addressing the technological requirements that each field demands. In this sense, the development of on-chip instruments such as optical sensors, high resolution spectrometers, or sophisticated beam combiners, is currently of high interest for the previous mentioned applications [1,2,5,6,7].Although several MIR two-dimensional (2D) planar schemes have been recently developed [8,9], these are all based on multiple-step surface deposition and processing techniques, which place inherent limits to the device design and capabilities. In this Letter, we report the single-step fabrication of three-dimensional (3D) MIR photonic circuits inside chalcogenide glass, by means of ultrashort-pulse direct laser writing (DLW) [10][11][12][13][14]. We show that the MIR waveguide cores can be tailored in both size and refractive index, and can also be spatially positioned at will inside the material, making the chip extremely robust against mechanical stress, vibrations, humidity, and temperature changes [11]. Moreover, we also evidence that the useful range of these DLW waveguides is, as suspected [12], ultimately limited by the transparency range of the material used, and not by the fabrication technique.In this work, high quality research and commercial chalcogenide sulphide glasses were used, both of which are free of highly toxic arsenic compounds. These glasses were commercial GaLaS (here after GLS) [14] and the research composition 75GeS2-15Ga2S3-4CsI-2Sb2S3-4SnS (here after GCIS) [15]. The MIR transmission upper limit of commercial GLS is known to be ~10 µm [14], while for GCIS we measured a slightly higher transmission upper limit of ~11 µm, as it is shown in Figure 1(a).
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.