A.A. Anderson

Laser operation of an Nd:Gd3Ga5O12 thin‐film optical waveguide fabricated by pulsed laser deposition

We report the laser operation of a thin-film waveguide structure grown by the pulsed laser deposition technique. A 2.7-µm-thick crystalline film of neodymium doped Gd3Ga5O12 (Nd:GGG) lases at a wavelength centered at 1.06µm when pumped by a Ti:sapphire laser at 808 nm.

TI:SAPPHIRE PLANAR WAVEGUIDE LASER GROWN BY PULSED LASER DEPOSITION

We document the lasing performance of a waveguiding layer of Ti:sapphire, of ~12-mum thickness, grown by pulsed laser deposition from a 0.12-wt.% Ti(2)O(3) Ti:sapphire single-crystal target onto an undoped z-cut sapphire substrate. Lasing around 800 nm is observed when the waveguide layer is pumped by an argon-ion laser running on all-blue-green lines, with an absorbed power threshold of 0.56 W, with high-reflectivity (R>98%) mirrors. With a 5% pump duty cycle and a T=35% output coupler, a slope efficiency of 26% with respect to absorbed power is obtained, giving quasi-cw output powers in excess of 350 mW.

Growth of Ti:sapphire single crystal thin films by pulsed laser deposition

This paper documents the growth of single crystal Ti:sapphire thin films, typically 10µm thick, on undoped sapphire substrates using Pulsed Laser Deposition from a Ti:sapphire single crystal target with a doping level of 0.1 % wt Ti2O3. These thin films are shown to have very high crystal quality using Ion Beam Channelling and X-Ray Diffraction Techniques. The degree of titanium incorporation into the films is investigated using Inductively Coupled Plasma Mass Spectrometry and Particle Induced X-ray Emission. These techniques show that levels of up to 0.08% wt Ti2O3 are present in the deposited layers.

Performance of a low loss pulsed laser deposited Nd:Gd3Ga5O12 waveguide laser at 1.06µm and 0.94µm

We report the laser performance of a low-propagation-loss neodymium-doped Gd(3)Ga(5)O(12) (Nd:GGG) waveguide fabricated by pulsed-laser deposition. An 8- mum -thick crystalline Nd:GGG film grown upon an undoped Y(3)Al(5)O(12) substrate lases at 1.060 and 1.062 microm when pumped by a Ti:sapphire laser operating at 740 or 808nm.Using a 2.2% output coupler, we observed a 1060-nm laser threshold of 4mW and a slope efficiency of 20%. Laser action was also achieved, for what we believe is the first time in Nd:GGG, on the quasi-three-level 937-nm transition. With a 2% output coupler at this wavelength a laser threshold of 17mW and a 20% slope efficiency were obtained. This demonstration of low propagation loss combined with the fact that these waveguides have a very high numerical aperture (0.75) makes pulsed-laser-deposited thin films attractive for high-power diode-pumped devices.

Photosensitivity of lead germanate glass waveguides grown by pulsed laser deposition.

We report very large photoinduced refractive-index changes Dn, of the order of ~10(2), in lead germanate glass waveguides grown by pulsed-laser deposition. The magnitude of Dn was derived from measurements of diffraction efficiency for gratings written by exposure to 244-nm light through a phase mask, whereas the sign of Dn was determined from ellipsometric data. Results are shown for films grown under oxygen pressures ranging from 1 chi 10(-2) to 6 chi 10(-2)mbars (1.33mbars=1 Torr).

Low loss (0.5 dB/cm) Nd:Gd3Ga5O12 waveguide layers grown by pulsed laser deposition

Nd:Gd3Ga5O12 planar waveguides, with significantly improved optical properties over those previously reported, have been fabricated on Y3Al5O12 substrates by pulsed laser deposition. Waveguide losses as low as 0.5 dB/cm have been obtained, determined by measuring the absorbed power lasing threshold with different output coupler reflectivities for both the 1060 nm and 937 nm lasing wavelengths. This order of magnitude improvement in waveguide loss is attributed to the much improved surface morphology and lower particulate count of the thin film samples.

Planar laser waveguides of Ti:sapphire, Nd:GGG and Nd:YAG grown by pulsed laser deposition

Highly efficient laser action is demonstrated in epitaxially grown Nd:GGG and Ti:sapphire layers. Waveguide losses as low as 0.5 dB/cm are achieved in films of low particulate content, high homogeneity and improved surface morphology obtained by optimized pulsed laser deposition (PLD) configurations. Low threshold laser emission is observed at 800 nm for Ti:sapphire, and at 1060 nm and 937 nm for Nd:GGG waveguides, with slope efficiencies of 26% and 20% respectively. These results verify the versatility of PLD schemes in the fabrication of novel optoelectronic structures.

Growth and characterization of pulsed laser deposited lead germanate glass optical waveguides

AbstractLead germanate thin films have been grown on BK7 and silica substrates, using pulsed excimer laser deposition(PLD) at wavelengths of 193 and 248 nm, from a bulk lead germanate target under various partial pressures of oxygen.The films produced vary in colour from brown, through clear, to yellow, and a parametric study has been undertaken ofthe film properties as a function of the growth conditions. The measured losses of the lead germanate films grown onglass substrates varied from ˘2.5 to 7 dB cm y1 depending on the oxygen partial pressure used. O 1999 Elsevier ScienceB.V. All rights reserved. 1. IntroductionPulsed laser deposition (PLD) has been exten-sively researched within the past decade as acomparatively fast, easy, and flexible technique forgrowing thin films of a wide range of materials [1].Amorphous, polycrystalline, and single crystallayers are routinely grown, depending on experi-mental parameters that include target composi-tion, substrate temperature, target–substratedistance, and the presence of an ambient gas, of-ten oxygen, at moderately low partial pressures.Recent successes in crystalline growth by PLDhave permitted the demonstration of e†cient la-sing action in 2–10 lm thick layers of gadoliniumgallium garnet, GGG, grown on YAG [2,3], andalso Ti:sapphire, grown on undoped sapphire [4].The losses reported in Ref. [3], of 0.3–0.5dB cm

Waveguiding pulsed laser deposited Ti:sapphire layers on quartz

Waveguiding thin films of Ti:sapphire were successfully grown on quartz. substrates by the technique of pulsed laser deposition from crystalline targets of various Ti,O, concentrations. The XRD spectra, titanium concentration, index of refraction, waveguiding properties and losses, and luminescence spectrum of films were studied. The refractive index of the films increases by 0.002 with change of dopant concentration of 0.37 wt.% of Ti,O,. The waveguide losses of a value of - 6.5 dB/cm for I pm film thickness were measured. 0 1998 Elsevier Science S.A. All rights reserved.

Waveguiding and Crystallographic Properties of Single Crystal Ti:Sapphire Layers Produced by Pulsed Laser Deposition

Layers of Ti:Sapphire were deposited over a range 1300K-1700K, with thicknesses between 1-82 microns on sapphire substrates. These were crystalline over the entire range. Waveguiding was observed without any additional co-dopants.