J. Rickards

Planar waveguide lasers by proton implantation in Nd:YAG crystals.

The performance of CW Nd:YAG waveguide lasers operating at 1.06 microm at room temperature is described. The waveguides were fabricated by proton implantation and the main differences in the process of fabrication were the angle of implantation and the total dose implanted. The characterization of the waveguide refractive index profile induced by proton implantation and the main laser characteristics i.e., slope efficiency and threshold are presented.

Optical channel waveguides by proton and carbon implantation in Nd:YAG crystals

In this work the formation of optical channel waveguides in Nd:YAG crystals by either proton or carbon implantation is reported. The channel waveguides were obtained by a single implantation process through an electroformed mask of nickel-cobalt alloy. Experimental measurements of the optical properties of these waveguides are presented.

Optical waveguides in Nd:YAG by proton implantation

Proton implantation has been used to produce optical waveguides in Nd:YAG. Two- and four-implant guides have been characterised by the dark mode method and by spectroscopic studies. A very small index enhancement was obtained as it was expected in this material as well as other insulators. It is shown that the luminescence properties of the Nd ions are not significantly altered by the ion beam process, thus maintaining the crystal quality in the guiding region.

Optical waveguides formed in Nd:YVO4 crystals by C2+ implantation

This work reports the formation of planar and channel waveguides in Nd:YVO4 by carbon implantation, using doses as low as 5 × 1014 ions/cm2. The analysis includes refractive index profiles, propagation losses and spectroscopic properties. The results indicate that there is an index convergence, the ordinary index increases while the extraordinary index decreases. The spectroscopic studies show that emission bands coming from the 4F3/2 level are not altered by the ion beam process, shedding light on the potential of carbon implanted waveguides for laser integrated devices.

Laser emission in proton-implanted Nd:YAG channel waveguides.

The performance of lasers based on channel waveguides produced by proton implantation in Nd:YAG crystals through an electroformed mask is reported. The fabrication method used can produce several waveguide lasers in the crystal by a single implantation process with very good optical performance. The analysis and comparison of the main laser emission features, as well as the propagation losses of these waveguides, by using different output couplers in the laser cavity is also presented.

Waveguiding properties in Yb:YAG crystals implanted with protons and carbon ions.

We report the fabrication and analysis of optical waveguides in Yb:YAG crystals using either proton or carbon ion implantation. Planar waveguides were obtained by implanting the whole surface of the crystals. Channel waveguides were defined using an electroformed mask with apertures of 10, 15, and 20 micrometers in width. The waveguiding properties of the structures were analyzed, showing good light confinement based on the transversal mode distribution and optical transmission measurements. The spectroscopic properties of the Yb ions in the YAG host are preserved after the implantation process, which demonstrates the potential of this technique for tailoring microcomponents for integrated optics applications. In particular, the Yb:YAG waveguides have the potential to operate as miniature lasers.

Analysis of the absorption coefficient in carbon implanted Nd:YVO4 by an annealing process

This work reports the behaviour of the absorption coefficient in a C2+-implanted Nd:YVO4 crystal by successive annealing steps. The absorption coefficient was monitored with respect to time and temperature after an annealing process. Firstly, the annealing duration increased in a constant form keeping a constant temperature and secondly, the annealing temperature was increased with equal time intervals. The results indicate that the variation of the absorption coefficient has an exponential behaviour.

Cooperative emission in ion implanted Yb:YAG waveguides

In this work, we report the analysis of spectroscopic properties of waveguides fabricated by ion implantation in YAG doped with Yb3+ ions. Three emission bands were detected in the blue, green and red regions under 970-nm excitation. The strong blue-green emission can be explained by a cooperative process between ytterbium ion pairs, leading to emission centered at 514 nm. The additional blue bands as well as green and red emission bands are attributed to the presence of Tm3+ and Er3+ traces. The results include absorption and emission curves as well as decay time rates.

Self-pulsing behavior in a Nd:YAG ion-implanted waveguide laser

We report the observation of sustained self-pulsing behavior of the output of a channel waveguide Nd:YAG laser under a CW pump. The duration and repetition rate of the pulses observed were dependent on the pumping power. At the maximum pumping power available (44 mW of absorbed power), the pulse duration was around ∼40 ns, and the pulse repetition rate was ∼1.4 MHz. We discuss the possible physical mechanisms that generate the pulsing behavior, and their implications on the observed pump-power dependence of the repetition rate.