Now showing items 11-30 of 32

  • High quality electron beams from a laser wakefield accelerator 

    Wiggins, S. M.; Shanks, R. P.; Issac, R. C.; Welsh, G. H.; Anania, M. P.; Brunetti, E.; Vieux, G.; Cipiccia, S.; Ersfeld, B.; Islam, M. R.; Burgess, R. T. L.; Manahan, G.; Aniculaesei, C.; Gillespie, W. A.; MacLeod, Allan M.; Jaroszynski, D. A. (Optical Society of America, 2010-07-01)
    Very stable, high quality electron beams (current ~ 10 kA, energy spread < 1%, emittance ~ 1π mm mrad) have been generated in a laser-plasma accelerator driven by 25 TW femtosecond laser pulses.
  • Holographic-recording improvement in a bismuth silicon oxide crystal by the moving-grating technique 

    Wang, Z. Q.; Gillespie, W. A.; Cartwright, Colin M. (Optical Society of America, 1994)
    We investigate the enhancement of the diffraction efficiency of dynamic gratings recorded in a bismuth silicon oxide crystal at large modulation by the moving-grating technique. The optimum fringe velocity for maximum ...
  • Hybrid diffractive-refractive 40° head-mounted display 

    Wang, Zhao-Qi; Yu, F.; Cartwright, Colin M.; Gillespie, W. A. (Elsevier, 2003)
    The design of a head-mounted display with a field of view of 40 degrees and suitable for use with a micro display of 17.5 mm diagonal is presented. It is a combination of a diffractive-refractive eyepiece with an appropriate ...
  • Hybrid diffractive-refractive ultra-wide-angle eyepieces 

    Wang, Zhao-Qi; Zhang, Hui-Juan; Fu, Ru-Lian; Mu, Guo-Guang; Lu, Zhen-Wu; Cartwright, Colin M.; Gillespie, W. A. (Elsevier, 2002)
    Two kinds of hybrid diffractive-refractive ultra-wide-angle (70°) eyepieces are designed which are with considerably reduced apparent size and weight and with comparable or improved aberrations as compared with the ...
  • Longtitudinal electron beam diagnostics via upconversion of THz to visible radiation 

    Berden, G.; van der Meer, A. F. G.; Jamison, S. P.; MacLeod, Allan M.; Gillespie, W. A.; Phillips, P. J. (2009)
    Longitudinal electro-optic electron bunch diagnostics has been successfully applied at several accelerators. The electro-optic effect can be seen as an upconversion of the Coulomb field of the relativistic electron bunch ...
  • Narrow spread electron beams from a laser-plasma wakefield accelerator 

    Wiggins, S. M.; Anania, M. P.; Brunetti, E.; Cipiccia, S.; Ersfeld, B.; Islam, M. R.; Issac, R. C.; Raj, G.; Shanks, R. P.; Vieux, G.; Welsh, G. H.; Gillespie, W. A.; MacLeod, Allan M.; Jaroszynski, D. A. (SPIE, 2009)
    The Advanced Laser-Plasma High-Energy Accelerators towards X-rays (ALPHA-X) programme is developing laserplasma accelerators for the production of ultra-short electron bunches with subsequent generation of incoherent ...
  • An optical matched filter using a quantized amplitude compensation technique 

    Wang, Z. Q.; Cartwright, Colin M.; Gillespie, W. A. (Elsevier, 1993)
    Starting from the amplitude-encoded binary phase-only filter, a 4-grey level quantized amplitude compensated matched filter is proposed. Computer simulations show that amplitude quantization has little effect on the filter ...
  • Optical pattern recognition using a synthetic discriminant amplitude-compensated matched filter 

    Wang, Z. Q.; Gillespie, W. A.; Cartwright, Colin M.; Soutar, C. (Optical Society of America, 1993)
    A technique for optical pattern recognition using an amplitude-compensated matched filter is presented. With the synthetic discriminant function in a matched spatial filtering application an iterative technique is employed ...
  • Real-time color image correlation with a color liquid-crystal television and a Fresnel holographic filter 

    Wang, Z. Q.; Cartwright, Colin M.; Soutar, C.; Gillespie, W. A. (Optical Society of America, 1993)
    Incoherent color image correlation with a multiwavelength Fresnel holographic filter and a color liquid-crystal television as a real-time input device is demonstrated.
  • Real-time computer-aided multiplexed optical intensity correlator using Fresnel holographic filters and a liquid crystal television 

    Wang, Z. Q.; Gillespie, W. A.; Cartwright, Colin M.; Soutar, C. (Elsevier, 1991)
    A real-time computer-aided optical intensity correlator using multiplexed Fresnel holographic filters (FHFs) and a liquid crystal television (LCTV) is described. This technique is characterized by the following. The spatially ...
  • Real-time edge-enhanced object correlation using incoherent readout of photorefractive BSO 

    Wang, Z. Q.; Soutar, C.; Gillespie, W. A.; Cartwright, Colin M. (Elsevier, 1993)
    Real-time edge-enhanced image correlation using the incoherent readout of a dynamic hologram recorded in BSO crystal is reported for the first time. A system is described which records the Fresnel transform of the input ...
  • Real-time intensity correlation with a synthetic discriminant function filter 

    Wang, Z. Q.; Cartwright, Colin M.; Gillespie, W. A. (Optical Society of America, 1994)
    Real-time optical intensity correlation with a synthetic discriminant function (SDF) filter has been realized. The computed SDF data are fed into an Epson liquid-crystal television to create the optical reference signal. ...
  • Real-time optical intensity correlator using photorefractive BSO and a liquid crystal television 

    Soutar, C.; Wang, Z. Q.; Cartwright, Colin M.; Gillespie, W. A. (Taylor & Francis, 1992)
    We demonstrate the implementation of an optical intensity correlator using Bi12SiO20 (BSO) as a dynamic holographic medium. The advantages of this correlator are large tolerance in the placement of input objects and BSO ...
  • Single shot longitudinal bunch profile measurements by temporally resolved electro-optical detection 

    Phillips, P. J.; Gillespie, W. A.; Steffen, B.; Knabbe, E-A.; Schmidt, B.; Schmüser, P.; Jamison, S. P.; Berden, G.; van der Meer, A. F. G.; MacLeod, Allan M. (Joint Accelerator Conferences Website, 2007)
    For the high gain operation of a SASE FEL, extremely short electron bunches are essential to generate sufficiently high peak currents. At the superconducting linac of FLASH at DESY, we have installed an electro- optic ...
  • Single-shot electron-beam bunch length measurements 

    Wilke, I.; MacLeod, Allan M.; Gillespie, W. A.; Berden, G.; Knippels, G. M. H.; van der Meer, A. F. G. (American Physical Society, 2002-03)
    We report subpicosecond electro-optic measurements of the length of individual relativistic electron bunches. The longitudinal electron-bunch shape is encoded electro-optically on to the spectrum of a chirped laser pulse. ...
  • Single-shot longitudinal bunch profile measurements at FLASH using electro-optic detection: Experiment, simulation and validation 

    Steffen, B.; Knabbe, E. A.; Schlarb, H.; Schmidt, B.; Schmuser, P.; Gillespie, W. A.; Phillips, P. J.; Jamison, S. P.; Berden, G.; van der Meer, A. F. G.; MacLeod, Allan M. (Joint Accelerator Conferences Website, 2007)
    At the superconducting linac of FLASH at DESY, we have installed an electro-optic (EO) experiment for singleshot, non-destructive measurements of the longitudinal electric charge distribution of individual electron bunches. ...
  • Single-shot longitudinal bunch profile measurements at FLASH using electro-optic detection: experiment, simulation, and validation. 

    Steffen, B.; Knabbe, E-A.; Schlarb, H.; Schmidt, B.; Schmüser, P.; Gillespie, W. A.; Phillips, P. J.; Jamison, S. P.; Berden, G.; van der Meer, A. F. G.; MacLeod, Allan M. (2007)
    At the superconducting linac of FLASH at DESY, we have installed an electro-optic (EO) experiment for single- shot, non-destructive measurements of the longitudinal electric charge distribution of individual electron ...
  • Temporally resolved electro-optic effect 

    Jamison, S. P.; MacLeod, Allan M.; Berden, G.; Jaroszynski, D. A.; Gillespie, W. A. (Optical Society of America, 2006-06)
    The electro-optic effect between an ultrafast optical probe pulse and an ultrashort terahertz pulse is shown to depend on the time derivatives of the product of the probe and the terahertz electric fields. Application of ...
  • Tracking novelty filter using transient enhancement of gratings in photorefractive BSO 

    Soutar, C.; Cartwright, Colin M.; Gillespie, W. A.; Wang, Z. Q. (Elsevier, 1991-11)
    The operation of novelty filtering is demonstrated using a hybrid optical and digital system. Dynamic gratings are written in photorefractive Bi12SiO20 at 514 nm and read out at 633 nm. The transient properties of the ...
  • An ultrashort pulse ultra-violet radiation undulator source driven by a laser plasma wakefield accelerator 

    Anania, M. P.; Brunetti, E.; Wiggins, S. M.; Grant, D. W.; Welsh, G. H.; Issac, R. C.; Cipiccia, S.; Shanks, R. P.; Manahan, G. G.; Aniculaesei, C.; van der Geer, S. B.; de Loos, M. J.; Poole, M. W.; Shepherd, B. J. A.; Clarke, J. A.; Gillespie, W. A.; MacLeod, Allan M.; Jaroszynski, D. A. (American Institute of Physics (AIP), 2014-06-30)
    Narrow band undulator radiation tuneable over the wavelength range of 150–260 nm has been produced by short electron bunches from a 2 mm long laser plasma wakefield accelerator based on a 20 TW femtosecond laser system. ...