Two-Pulse Ionization Injection into Quasi-Linear Laser Wakefields

We describe a scheme for controlling electron injection into the quasi-linear wakefield driven by a guided drive pulse via ionization of a dopant species by a collinear injection laser pulse with a short Rayleigh range. The scheme is analyzed by particle in cell simulations which show controlled injection and acceleration of electrons to an energy of 370 MeV, a relative energy spread of 2%, and a normalized transverse emittance of 3.0 {\mu}m. This is an arXiv version of the original APS paper. It should be cited as N. Bourgeois, J. Cowley, and S. M. Hooker, Phys. Rev. Lett. 111, 155004 (2013). APS link here: http://link.aps.org/doi/10.1103/PhysRevLett.111.155004Comment: 5 pages, 4 figure

Quasi-phase-matching of high-order-harmonic generation using multimode polarization beating

The generalization of quasi-phase-matching using polarization beating and of multimode quasi-phase-matching (MMQPM) for the generation of high-order harmonics is explored, and a method for achieving polarization beating is proposed. If two (and in principle more) modes of a waveguide are excited, modulation of the intensity, phase, and/or polarization of the guided radiation will be achieved. By appropriately matching the period of this modulation to the coherence length, quasi-phase-matching of high-order-harmonic radiation generated by the guided wave can occur. We show that it is possible to achieve efficiencies with multimode quasi-phase-matching greater than the ideal square wave modulation. We present a Fourier treatment of QPM and use this to show that phase modulation, rather than amplitude modulation, plays the dominant role in the case of MMQPM. The experimental parameters and optimal conditions for this scheme are explored

Complete spatial characterization of an optical wavefront using a variable-separation pinhole pair

We present a technique for measuring the transverse spatial properties of an optical wavefront. Intensity and phase profiles are recovered by analysis of a series of interference patterns produced by the combination of a scanning X-shaped slit and a static horizontal slit; the spatial coherence may be found from the same data. We demonstrate the technique by characterizing high harmonic radiation generated in a gas cell, however the method could be extended to a wide variety of light sources.Comment: 4 pages, 3 figures, 1 tabl

Deliberately Personal: The politics of tobacco control in NSW

In this paper we examine some of the main features of public discourse concerning tobacco control, analysing parliamentary debate in New South Wales between 1980 and 2003. We ask both how deeply tobacco industry discursive frames (eg, the ‘right to smoke’) penetrated and organized parliamentary discourse and identify what kinds of ideas were mobilized to justify tobacco control despite government reluctance to intervene. We find that the overall evolution of tobacco control policy was shaped by legislators’ commitment to the ideals of deliberative democracy. We argue firstly that parliamentary debate on tobacco control was conducted in highly moralised language that effectively excluded the tobacco industry’s arguments. Secondly, we show that this discourse was constructed and validated through the extensive use of personal anecdote and references, through which MPs sought to reflect public opinion and engage in authentic deliberation. Finally we argue that MPs positioned this concern for authentic deliberation as part of the debate on tobacco itself, associating tobacco control with ideal government

Learning, becoming, being: The Journey from student teacher to full teacher registration.

This research aims to investigate the journey of student teachers as they complete their programme of study and begin their careers in the teaching profession. There is little documented evidence of what, if any, impact an initial teacher education programme can have on teachers as they move through the profession – from student to newly qualified teacher to fully certificated teacher. This project will explore this relationship and how graduates call on the knowledge acquired in their initial teacher education qualification to inform their practice as teachers. The Teaching Council of Aotearoa New Zealand is currently undertaking a project examining Future Focussed Initial Teacher Education this project will complement this work as well as the Ministry of Education's Draft Strategic Plan for Early Learning. The aims of both of these pieces of work are to provide quality learning outcomes for all children and effective teaching strategies. This project will explore these aims and the relationship between an initial teacher education programme. The research is a longitudinal study with three phases. The first phase investigated graduates perceptions of preparedness to teach and as they enter the workforce how their field-based initial teacher education training has contributed to this. The next two phases will follow the newly qualified teachers as the transverse the induction and mentoring towards full certification. In these two phases of this research the participants will become teacher researchers. This presentation reports on the findings of the first phase which included a survey and semi-structured interview

Traversing the journey from student teacher to full teacher certification

This research aims to investigate the journey of student teachers as they complete their program of study and begin their careers in the teaching profession. There is little documented evidence of what, if any, impact an initial teacher education program can have on teachers as they move through the profession – from student to newly qualified teacher to fully certificated teacher. This project will explore this relationship and how graduates call on the knowledge acquired in their initial teacher education qualification to inform their practice as teachers. The Teaching Council of Aotearoa New Zealand is currently undertaking a project examining Future Focussed Initial Teacher Education this project will complement this work as well as the Ministry of Education's Draft Strategic Plan for Early Learning. The aims of both of these pieces of work are to provide quality learning outcomes for all children and effective teaching strategies. This project will explore these aims and the relationship between an initial teacher education program. Abstracts—Day 1: Wednesday, July 3rd ● 33 The research is a longitudinal study with three phases. The first phase investigated graduates perceptions of preparedness to teach and as they enter the workforce how their field-based initial teacher education training has contributed to this. The next two phases will follow the newly qualified teachers as the transverse the induction and mentoring towards full certification. In these two phases of this research the participants will become teacher researchers

Combined visible and near-infrared OPA for wavelength scaling experiments in strong-field physics

We report the operation of an optical parametric amplifier (OPA) capable of producing gigawatt peak-power laser pulses with tunable wavelength in either the visible or near-infrared spectrum. The OPA has two distinct operation modes (i) generation of >350 uJ, sub 100 fs pulses, tunable between 1250 - 1550 nm; (ii) generation of >190 uJ, sub 150 fs pulses tunable between 490 - 530 nm. We have recorded high-order harmonic spectra over a wide range of driving wavelengths. This flexible source of femtosecond pulses presents a useful tool for exploring the wavelength-dependence of strong-field phenomena, in both the multi-photon and tunnel ionization regimes.Comment: 14 pages, 9 figures, This paper was published in Proceedings of SPIE 10088, Nonlinear Frequency Generation and Conversion: Materials and Devices XVI, doi 10.1117/12.225077