Continuous-wave laser action at λ=1064.3 nm in proton- and carbon-implanted Nd:YAG waveguides

Abstract

This work reports continuous laser oscillation at ϭ1064.3 nm at room temperature in Nd:YAG planar waveguides fabricated by two different techniques: proton implantation with a multi-implant of energies around 1 MeV and carbon implantation with a single-implant at an energy of 7 MeV. Threshold powers of 11 and 22 mW and slope efficiencies of 7% and 9% were achieved in the proton-and carbon-implanted guides, respectively. The laser outputs show a very high stability operating in cw regime at room temperature. © 2003 American Institute of Physics. ͓DOI: 10.1063/1.1628817͔The field of waveguide lasers based on integrated-optics technology has created much interest during the last years and recently. The confinement of light in optical waveguides maintains a small spot size and hence a high intensity over lengths than would normally be forbidden by diffraction. If the waveguide is doped with an active ion, the enhancement of laser efficiency is allowed and, therefore, extremely low laser thresholds can be achieved. The excellent laser properties of Nd 3ϩ ions combined with the characteristics of the YAG host allow the development of compact and efficient amplifiers and solid-state lasers, preserving the crystal quality and homogeneity. Several techniques, such as epitaxial growth of Nd:YAG layers on pure YAG substrates, 1 or helium implantation on Nd-doped YAG crystals, 2 have been proposed to fabricate optical waveguides, allowing high slope efficiency and low threshold laser operation at 1.06 m. In fact, Nd:YAG was the first dielectric material that demonstrated the suitability of the ion implantation technique to fabricate waveguide lasers. The ion implantation process produces radiation damage at the end of the ion track ͑nuclear stopping region͒ of the crystal, giving rise to a decrease of the refractive index in many dielectric materials.4 This low-density region generates an optical barrier that confines the radiation, producing an optical waveguide. Typically, a 2.8 MeV He ϩ ion energy produces an optical barrier situated at around 6 m beneath the surface. An alternative way to fabricate wider waveguides using ion implantation is to use protons instead of He ϩ ions, because, for a given energy, the ion range is much deeper in the case of lighter ions, 5 this fact being advantageous when infrared light propagates along the waveguide. Instead of using light ions, optical waveguides can also be produced implanting heavy ions, 6 such as carbon, 7 for which a greater index decrease in the nuclear region is produced for a given dose. This leads to the formation of a higher optical barrier, which implies a reduction of tunneling losses. In this work, the characterization of Nd:YAG waveguide lasers operating at 1.06 m fabricated by either proton or carbon implantation is reported. The characterization includes the laser excitation range, the pump powers needed to reach laser oscillation as well as the slope efficiencies for both implanted waveguides. The experimental results combined with the theoretical estimations ...

Optically pumped planar waveguide lasers, Part I: Fundamentals and fabrication techniques

“…In contrast, little work has been reported on laser operation of planar waveguides produced by ion-implantation in rare-earth doped glasses, with the only successful demonstration of laser oscillation being that in Tm-doped germanate glass [329]. Most of these laser sources were produced by implantation with helium ions (He + ) [320][321][322][323][324][325][326][327]329], however successful use of carbon ions (C + ) was also reported [319,328]. Recently, laser operation was demonstrated in YAG:Nd Proton implantation has also attracted interest for fabrication of waveguide lasers primarily for its potential to induce deeper damage profiles as a result of the larger depths that protons can penetrate in the substrate compared to higher-mass ions.…”

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

“…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.…”

Low‐dose ion implanted active waveguides in Nd3+ doped near‐stoichiometric lithium niobate: promising candidates for near infrared integrated laser

“…A few chemical techniques, such as Ti or Zn ion indiffusion [11,12] and proton exchange [13], have been utilized to form waveguides in CLN crystals; however, it should be pointed out that these conventional methods are proved to be less acceptable for SLN wafers, since the indiffusion coefficients of the metal ions are much lower in SLN [7], and also because the incorporation of protons into SLN replace original Li ions, resulting in a reduction of [Li]/[Nb] ratio in the waveguides, which causes a degradation in the SLN original properties. Mainly based on a physical mechanism, ion implantation has been proved to be a superior technique to produce waveguides with good reproducibility with a wide applicability to numerous materials [14,15], including many laser crystals such as Nd:YVO 4 [16], Nd:YAG [17], Nd:YLiF 4…”