Anisotropic focusing characteristics of micro-domain structures within crystalline Sr_0.61Ba_0.39Nb₂O₆ : the crystal ball

We report the anisotropic focusing characteristics of a spherically configured region of micro-domains that have been induced within a cubic shaped crystal of Ce:doped Sr0.61Ba0.39Nb2O6. The internal spherical structure focuses extraordinary polarised light, but not ordinary polarised. The spherical region, which is easily observed via scattering, is formed as the crystal cools down, after a repoling cycle through the Curie temperature, with an applied field. Analytic modelling of the thermal gradients that exist within the crystal during cooling reveals a small (< 1°) temperature difference between the central and outside regions. The similarity in shape between these temperature profiles and the observed scattering region suggests a possible mechanism for the growth of this spherical micro-domained structure

Nano-droplets deposited in microarrays by femtosecond Ti:sapphire laser-induced forward transfer

The authors present the deposition of nanoscale droplets of Cr using femtosecond Ti:Sapphire Laser-Induced Forward Transfer. Deposits around 300 nm in diameter, significantly smaller than any previously reported, are obtained from a 30 nm thick source film. Deposit size, morphology, and adhesion to a receiver substrate as functions of applied laser fluence are investigated. We show that deposits can be obtained from previously irradiated areas of the source material film with negligible loss of deposition quality, allowing sub-spot size period microarrays to be produced without the need to move the source film

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 Y3Al5O12 substrate

Pulsed laser deposition for growth of high quality epitaxial garnet films for low threshold waveguide lasers

Pulsed laser deposition (PLD) is a mature technique capable of producing extremely high quality epitaxial single crystalline films. We have grown Nd:doped garnet films of GGG (Gd The talk will summarise our progress using conventional (single beam) PLD in thin-film and waveguide growth, using both nanosecond and femtosecond lasers, and also introduce our new directions in tri-beam PLD (three targets, three lasers) for growth of some interesting, complex and perhaps impossible structures, such as Gaussian doping, internal voids and even helically doped structures

Science with coffee and hobnobs

Many parents or guardians of primary school pupils have little knowledge of science, and many lack confidence in their ability to help their children, though most welcome the chance to do so. We describe our experiences running a series of meetings in the form of coffee sessions at local primary schools, where parents can increase their knowledge and confidence in the science their children study, and engage in simple experiments with their children to apply the knowledge they gain. We discuss how this programme can be instrumental in improving the profile of scientific education and scientific careers for children of a young age

Teaching and Doing Strategy as an Intentional Strategic Innovation Mindset

There are many important keys in learning, teaching, and doing strategy today. We propose rethinking the learning strategies employed at the MBA level to make the degree more relevant. Recent calls from academia and practice indicate the need to stress adaptability using soft knowledge and skills to make MBA courses more aligned with the realities of strategic decision-making in today’s business environments. We emphasize that while traditional strategic framework models and diagrams have their place, today’s professionals must be prepared to make decisions in unstructured and highly ambiguous situations that traditional models do not address

Temperature sensitivity of repoling in strontium barium niobate near to the glassy transition

We report the observation of an enhanced temperature sensitivity for transient repoling near to the domain freezing temperature in ferroelectric strontium barium niobate. This work has important consequences for the use of optical fields to control domain patterns in such materials. We model the repoling characteristics of the material using a Vogel-Fulcher type response and present results showing the degree of repoling as a function of field and temperature, for short duration repoling times

Phase conjugate fluorozirconate fibre laser operating at 800nm

We report phase-conjugate feedback into a fluorozirconate optical fiber amplifier at infrared wavelengths. By using a semiconductor laser diode at 807 nm, a grating is established in photorefractive BaTiO3 that, in the ring configuration, provides feedback into the amplifier necessary for laser action. Once written, the grating is self-sustaining, and lasing is observed even after the laser diode is removed

Crossing Cultures: Guides and Models for Development, Selection, and Application

Despite many calls for it, there has been little action toward an all-inclusive manuscript that is practical, empirically verified, and provides guidelines for becoming and remaining strategically culturally adaptive. Further, a tremendous number of current articles and books emphasize managing or leading in an era of globalization. To meet these calls to work, learn, and innovate across cultures, the goal must be to move from the mass of unrelated assertions to the weaving of co-created, manageable models that are useful in learning, teaching, and practice

Intensity-dependent thresholding and switching in the photorefractive bridge mutually pumped phase conjugator

Beam-intensity-ratio-dependent effects have previously been observed in several photorefractive mixing configurations. Here we report the observation of total input-intensity-dependent effects in the bridge mutually pumped phase conjugator, which results in optical thresholding and switching behavior. The cause of these effects is attributed to competition between bridge conjugation and self-pumped phase conjugation that results from different exponents in their measured intensity-dependent response times (10-90%), namely, τbridge is proportional to I-0.79 and τSPPC is proportional to I-0.38