The Microlase infrared diode laser has recently become available for retinal photocoagulation. It uses a laser beam with a large convergence angle (23 degrees). This gives rise to a laser beam with a relatively large cross section at the subject's pupil. In this study the pupillary area required to view the fundus at the slit-lamp with a 90-dioptre lens is determined. It is found that the pupil...

We demonstrate a novel method for improvement of spatial beam quality by use of the angular selectivity of a thick phase grating inserted into various laser cavities. Preliminary experiments with an intentionally degraded beam from a Nd:YVO4 laser have enhanced beam propagation factor M2 by a factor of 4.5. Operation with a broad-area laser diode in an external cavity with a thick grating was a...

A 15by 15-cm supersonic wind tunnel application of a one-dimensional laser beam scanning approach to shock sensing is presented. The measurement system design allowed easy switching between a focused beam and a laser sheet mode for comparison purposes. The scanning results were compared to images from the tunnel Schlieren imaging system. The tests revealed detectable changes in the laser beam i...

LLE Review, Volume 127 113 Beam-shaping applications in high-power laser systems have been presented in many different contexts such as the improvement of laser performance1 or the manipulation of laser–target interactions.2,3 These applications commonly employ static apodizers or deformable mirrors. Spatial-light modulators (SLM’s) are also popular beam-shaping devices. Because of their low da...

This first stage experiment is a Proof-of-Principle to support our novel vacuum laser acceleration (VLA) theory, published previously. Simulations show that based on current experimental conditions at the Brookhaven National Laboratory Accelerator Test Facility (ATF), an electron beam with initial energy of 15 MeV can get net energy gain from an intense CO2 laser beam. The difference of electro...

In this work, the machine dynamic response in Selective Laser Sintering is investigated with the purpose of determining the causes of scanning errors. Machine subcomponents are rst investigated to determine their potential eeects on the laser beam positional accuracy. The dynamics of the laser beam delivery system are identiied as the major contributor to deviations in the laser beam position. ...

We report generation of density modulation at terahertz (THz) frequencies in a relativistic electron beam through laser modulation of the beam longitudinal phase space. We show that by modulating the energy distribution of the beam with two lasers, density modulation at the difference frequency of the two lasers can be generated after the beam passes through a chicane. In this experiment, densi...

Generation of “Laser Light Sheet” beams and linear laser spots characterized by uniform irradiance distribution is important in various laser techniques like Particle Image Velocimetry (PIV), Laser-Induced Fluorescence (LIF), hardening, annealing, cladding, uniform laser illumination of linear spatial light modulators. This task can be successfully solved with using refractive beam shaping opti...

2014 The detection of optical resonances by observation of the fluorescence light emitted from a fast atomic beam of Na interacting with a collinear laser beam is limited in sensitivity by optical pumping processes. In the experiment reported here, we take advantage of the optical pumping by using a second collinear laser beam, achieving then a gain in fluorescence signal. The effects of the la...

In this paper, we propose a scheme to generate tunable coherent X-ray radiation for future light source applications. This scheme uses an energy chirped electron beam, a laser modulator, a laser chirper and two bunch compressors to generate a prebunched kilo-Ampere current electron beam from a few tens Ampere electron beam out of a linac. The initial modulation energy wavelength can be compress...