Generation of high-order optical vortices using directly machined spiral phase mirrors

We report on the generation of high-order optical vortices by spiral phase mirrors. The phase mirrors are produced by direct machining with a diamond tool and are shown to produce high-quality optical vortices with topological charges ranging from 1 to 1000 at a wavelength of 532 nm. The direct machining technique is flexible and offers the promise of high-precision, large-diameter spiral phase mirrors that are compatible with high optical powers.Comment: 4 pages, 4 figure

Holographic optical trapping

Holographic optical tweezers use computer-generated holograms to create arbitrary three-dimensional configurations of single-beam optical traps useful for capturing, moving and transforming mesoscopic objects. Through a combination of beam-splitting, mode forming, and adaptive wavefront correction, holographic traps can exert precisely specified and characterized forces and torques on objects ranging in size from a few nanometers to hundreds of micrometers. With nanometer-scale spatial resolution and real-time reconfigurability, holographic optical traps offer extraordinary access to the microscopic world and already have found applications in fundamental research and industrial applications.Comment: 8 pages, 7 figures, invited contribution to Applied Optics focus issue on Digital Holograph

Lens Flare Attenuation Accelerator Design with Deep Learning and High-Level Synthesis

Lens flare artifacts are undesired visual distortions caused by stray light, which can negatively impact the integrity and quality of an image. These artifacts pose a significant challenge in industrial applications like automotive and surveillance, where the quality and reliability of input images from cameras are crucial. Artificial intelligence, particularly deep learning neural networks, have shown promising results in attenuating lens flare. In this work, a synthetic flare dataset is generated, and an iterative training process that includes evaluation of transfer learning is employed to develop FlareNet, the first compact and lightweight U-Net based model for lens flare reduction. The FlareNet architecture, with less than 150,000 parameters comprising convolutional layers, demonstrates improvement in image quality by reducing flare artifacts on synthetic test images and real-life images, indicating its potential for achieving visually satisfactory results despite having less than 0.5% of the weights of the state-of-the-art neural architecture used for this same application. To demonstrate the viability of using a model such as FlareNet as a hardware accelerator, the neural network is implemented in C++ using Vitis HLS. Synthesis and validation are performed using the Vitis tool, and reports are analyzed while experimenting with HLS optimization directives. Resource utilization of less than 20% on a Zeus Zynq UltraScale FPGA is shown but further work is needed to optimize the design for real-time applications and effectively deploy the solution on an FPGA.Lens Flare Attenuation Accelerator Design with Deep Learning and High-Level SynthesisacceptedVersio

Ambient environmental radiation monitoring at the Lawrence Livermore Laboratory

Thermoluminescence dosimetry is the principal means of measuring ambient $gamma$ radiation at the Lawrence Livermore Laboratory. These dosimeters are used at 12 perimeter locations and 41 locations in the off-site vicinity of the Laboratory, and are exchanged quarterly. Control dosimeters are stored in a 75- mm-thick lead shield located out-of-doors to duplicate temperature cycling of field dosimeters. Effect of dosimeter response to radiation in the shield is determined each quarter. Calibration irradiations are made midway through the exposure cycle to compensate for signal fading. Terrestrial exposure rates calculated from the activities of naturally occurring uranium, thorium, and potassium in Livermore Valley soils vary from 3 to 7 $mu$R/hr. Local inferred exposure rates from cosmic radiation are approximately 4 $mu$R/hr. TLD measurements are in good agreement with these data. Off-site and site perimeter data are compared, and differences related to Laboratory operations are discussed. (auth

Preliminary report on radiation-induced thermoluminescence in Climax Stock quartz monzonite

An examination has been made of the feasibility of using thermoluminescence (TL) for the self-dosimetry of the rock surrounding a canister of nuclear waste. The rock investigated was quartz monzonite from the Climax Stock, a granite intrusive at the Nevada Test Site. Samples of the rock were irradiated by {sup 60}Co to doses of 10{sup 3} to 10{sup 9} rads, then ground to a fine powder and read for TL response at a heating rate of 1{sup 0}C per second. Effects of total dose, thermal history after irradiation, grinding to a powder after irradiation, mineral composition, and powder grain size were investigated. All were found to be important, but with care, the use of TL in this manner appears promising

Socio-demographic, lifestyle and health characteristics among snus users and dual tobacco users in Stockholm County, Sweden

<p>Abstract</p> <p>Background</p> <p>Socio-demographic and lifestyle characteristics of snus users have not been systematically described. Such knowledge is pivotal for tobacco control efforts and for the assessment of health effects of snus use.</p> <p>Methods</p> <p>A cross-sectional study was conducted, based on the Stockholm Public Health Survey, including a population-based sample of 34,707 men and women aged 18-84 years. We examined how socio-demographic, lifestyle and health-related characteristics were associated with the prevalence of current daily snus use, smoking and dual tobacco use. Logistic regression was used to calculate odds ratios of prevalence (ORs) and 95% confidence intervals (CIs).</p> <p>Results</p> <p>Low educational level (OR = 1.60, CI = 1.41-1.81 and OR = 1.49, CI = 1.17-1.89, for men and women respectively), as well as occupational class and low income were associated with snus use. Some unfavourable lifestyle characteristics, including risky alcohol consumption (males: OR = 1.81, CI = 1.63-2.02; females: OR = 1.79, CI = 1.45-2.20), binge drinking and low consumption of fruit and vegetables were also associated with snus use. In contrast, physical inactivity and overweight/obesity were not, nor was perceived health. The prevalence of smoking followed steeper gradients for social as well as lifestyle characteristics. Overweight and obese men were however less often smokers. Perceived poor general health and psychological distress were highly related to smoking. Social disadvantage, as well as unhealthy lifestyle and self-reported poor health were strongly associated with dual use. There were limited differences between men and women.</p> <p>Conclusions</p> <p>The social, lifestyle and health profiles of exclusive snus users in Stockholm County are less favourable than those of non-users of tobacco, but more advantageous than those of exclusive smokers. This knowledge should guide tobacco control measures as well as the interpretation of health risks linked to snus use.</p