K.A. Sloyan

Growth of crystalline garnet mixed films, superlattices and multilayers for optical applications via shuttered Combinatorial Pulsed Laser Deposition

A range of crystalline garnet multilayer structures have been fabricated via multi-beam, multi-target PLD in conjunction with a system of mechanical shutters. Structures grown consisted of alternating Gd3Ga5O12 (GGG) and Gd3Sc2Ga3O12 (GSGG) layers on Y3Al5O12 (YAG) substrates, with both simple and chirped designs. Distinct layers are observed where layer thickness is around 2 nm or greater, although some layering may also be present at a sub-unit cell level. These structures demonstrate the viability of the shutter technique as a quick, simple fabrication method for a variety of optical multilayer structures.

Diode-end-pumped 1.2 W Yb:Y 2 O 3 planar waveguide laser

Fabrication, characterization and laser performance of a Watt-level ytterbium-doped yttria waveguide laser is presented. The waveguide was grown onto a YAG substrate by pulsed laser deposition and features a 6 µm thick ytterbium-doped yttria layer sandwiched between two 3 µm undoped yttria layers. The laser deposited film was characterized by X-ray diffraction, showing a high degree of crystallinity and analyzed spectroscopically, showing performance indistinguishable from previously reported bulk material. When pumped with 8.5 W from a broad area diode laser the waveguide laser produces 1.2 W of output at 1030 nm.

Diode-end-pumped 1.2W Yb:Y2O3 planar waveguide laser

Fabrication, characterization and laser performance of a Watt-level ytterbium-doped yttria waveguide laser is presented. The waveguide was grown onto a YAG substrate by pulsed laser deposition and features a 6 µm thick ytterbium-doped yttria layer sandwiched between two 3 µm undoped yttria layers. The laser deposited film was characterized by X-ray diffraction, showing a high degree of crystallinity and analyzed spectroscopically, showing performance indistinguishable from previously reported bulk material. When pumped with 8.5 W from a broad area diode laser the waveguide laser produces 1.2 W of output at 1030 nm.

Q-switched operation of a pulsed-laser-deposited Yb:Y 2 O 3 waveguide using graphene as a saturable absorber

The first, to the best of our knowledge, Q-switched operation of a pulsed-laser-deposited waveguide laser is presented. A clad Yb:Y(2)O(3) waveguide was Q-switched using an output coupling mirror coated with a single layer of graphene deposited by atmospheric pressure chemical vapor deposition. During continuous-wave operation, a maximum power of 83 mW at a slope efficiency of 25% was obtained. During Q-switched operation, pulses as short as 98 ns were obtained at a repetition rate of 1.04 MHz and a central wavelength of 1030.8 nm.

Laser operation of a Tm:Y2O3 planar waveguide

We demonstrate the first Tm-doped yttria planar waveguide laser to our knowledge, grown by pulsed laser deposition. A maximum output power of 35 mW at 1.95 μm with 9% slope efficiency was achieved from a 12 μm-thick film grown on a Y(3)Al(5)O(12) substrate.

Multi-beam pulsed laser deposition for advanced thin-film optical waveguides

We discuss our progress in the use of multiple laser beams and multiple targets for the pulsed laser deposition of thin films for waveguide laser and magneto-optic applications. In contrast to the more widely used single-beam/single-target geometries, having more than one laser-produced plume can allow tuning of the material properties and complex engineering of the deposited thin films. For optical applications - the majority of the work reported here - dopants can be selectively introduced, lattice mismatch and residual strain can be compensated, which is an important factor for successful growth of thin films of ~ tens of microns thickness, and refractive index values can be adjusted for fabrication of sophisticated waveguiding structures. We discuss mixed, layered, superlattice and Bragg reflector growth, which involve out-of-plane engineering of the film structure, and in-plane engineered geometries for designs relevant to thin-film disc lasing devices. Finally we briefly discuss our most recent use of multi-plume growth for magneto-optic thin films, which involves compositional tuning of final magnetic properties.

Crystalline garnet Bragg reflectors for high power, high temperature, and integrated applications fabricated by multi-beam pulsed laser deposition

Crystalline Bragg reflectors are of interest for high power, high temperature, and integrated applications. We demonstrate the automated growth of such structures by shuttered multi-beam pulsed laser deposition. Geometries include 145 layer stacks exhibiting >99.5% reflection and π phase-shifted designs. A crystalline grating strength-apodized sample was grown by mixing plumes to obtain layers with custom refractive indices. Peak reflection wavelength was tuneable with incident position, samples withstood temperatures of ∼750 °C, and film and substrate have been shown to withstand incident pulsed laser fluences of up to ∼33 J cm−2.

Thulium-doped yttria planar waveguide laser grown by pulsed laser deposition

Lasers operating in the 2 micron wavelength region are of particular interest for various applications in remote sensing/LIDAR, materials processing, and medical treatments. Thulium-doped media have several attractive features for generating light in this wavelength band, including a broad emission bandwidth, long-lived metastable states, absorption bands matched to high-power 0.8 mm diode-pump sources coupled with the potential for high quantum-efficiency due to a 2-for-1 cross-relaxation process. The sesquioxide crystal family is of considerable interest as a potential host due to their excellent thermo-optic characteristics and spectroscopic properties. A key challenge for this host material is its high-temperature growth requirements (some in excess of 2500 K for bulk crystals); as such there has been limited success in fabricating these crystals commercially. Here we report the first growth and lasing results (to the best of our knowledge) of a crystalline Tm:Y2O3 waveguide, fabricated via pulsed laser deposition (PLD).

Fabrication of crystalline Bragg reflectors for high power and integrated optical applications by multi-beam Pulsed Laser Deposition

Tunable crystalline Bragg reflectors for high temperature, high power and integrated optical applications were fabricated via multi-beam Pulsed Laser Deposition. Apodised, π phase-shifted and >;99% reflective quarter-wave structures are presented.

Emerging pulsed laser deposition techniques

The use of lasers for the deposition and processing of electronic and photonic materials is becoming increasingly widespread and advances in processing technology are reducing costs and increasing throughput. Laser deposition of photonic materials and laser processing techniques can produce high quality devices with novel properties. Part one covers laser deposition and growth of materials, including pulsed laser deposition and laser-induced self-assembly of semiconductors. Part two describes laser patterning and lithography techniques, such as 3D laser lithography. Part three looks at laser treatments to manipulate properties of photonic materials for applications such as optical storage, laser components, waveguides and displays.