Continuous-wave laser oscillation at 1.3μm in Nd:YAG proton-implanted planar waveguides

Abstract

This work reports continuous laser oscillation around 1.3 m at room temperature in Nd:YAG planar waveguides fabricated by MeV proton implantation. The performance of the waveguide lasers fabricated with different implantation parameters has been studied in terms of the threshold pump powers and slope efficiencies. The development of compact and efficient solid state lasers is becoming an important matter in the field of integrated optics. The waveguide configuration is necessary in applications such as optics communications and information technology due to its size and compatibility with semiconductor lasers and fiber optic technology.1 Optical waveguides doped with rare-earth ions can be used for the development of miniaturized lasers and amplifiers providing high slope efficiency and low pump thresholds.Ion beam implantation has proved to be an effective technique to fabricate optical waveguides in more than 60 materials.2 The damage caused by nuclear collisions during the implantation process reduces the physical density of the crystal, which results in a reduction of the refractive index. The low-density buried layer that is produced at the end of the ion track acts as an "optical barrier" that has a lower refractive index than the substrate.3 Thus, the region between this barrier and the surface is surrounded by regions of lower refractive index and can act as a waveguide. Nd:YAG was the first material in which such a structure was formed by ion implantation and where the suitability of this technique to fabricate waveguide lasers was demonstrated. 4 Laser oscillation in the cw regime in proton and carbon implanted Nd:YAG waveguides at 1064 nm has been recently reported, showing low pump thresholds and high stability.5 This work presents laser emission at 1338 nm obtained from proton-implanted waveguides, which corresponds to the second telecommunication window in silica optical fibers. Characteristics such as pump power thresholds and laser efficiencies are reported, and these data are compared with the performance of Nd:YAG waveguide lasers operating at 1.06 m.Two planar waveguides were fabricated by proton implantation in a 9SDH-2 Pelletron Accelerator using protons of several energies and different total doses. 6 Waveguide #1 was implanted with energies from 1.25 to 1 MeV at a total dose of 6 ϫ 10 6 ions/ cm 2 , while for waveguide #2 the implanted energies were from 1.15 to 1 MeV at an angle of 30°a nd a final dose of 5 ϫ 10 16 ions/ cm 2 . When a waveguide is formed by ion implantation, color centers are generated during the process, which would imply absorption losses in the waveguide.2 Therefore, an annealing step is necessary in order to reduce these losses. In the present work both Nd:YAG waveguides were introduced during half an hour in an open furnace operating at 400°C.To ascertain in which extent the spectroscopic properties of the neodymium ions are affected by the ion implantation process, a cw Ti:sapphire laser, with a tuning range between 750-850 nm, was used as excitation source and laun...

The fabrication of planar waveguides on Bi12TiO20 crystals by oxygen and helium ion implantation

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Low-loss planar and stripe waveguides in Nd3+-doped silicate glass produced by oxygen-ion implantation

“…3,4 Optical waveguides in Nd 3+ -doped materials have great potential for the development of compact and efficient waveguide lasers and amplifiers. 1,2 Excitation of the Nd 3+ ions leads to the population of the 4 G 7/2 level.…”

Femtosecond laser micromachined ridge waveguide lasers in Nd:YAG ceramics

“…Ion implantation, as one of the most successful methods for controlled material modifications at the micrometric scale, has been widely used to produce waveguides in versatile optical substrates, exhibiting unique capabilities to diverse materials. As a physical method, in principle, it does not rely on the chemical properties of the target materials [9,[13][14][15][16][17][18]. Fs-laser inscription is a powerful and feasible way to fabricate channel waveguide configurations and it has become increasingly attractive in recent years owing to the various practical applications in microstructuring of multiple materials [10][11][12][19][20][21][22][23][24][25].…”