We report on the generation of photonic nanojets, which resemble optical bottle beams. They are realized by manipulating the illumination of dielectric microspheres. As illumination we use the outer region of deliberately truncated Bessel-Gauss beam or a focused Gaussian beam with intentionally induced spherical aberrations. For the Bessel-Gauss beam possessing a single side lobe only, the nano...

Currently hard coherent x-ray radiation at high photon fluxes can only be produced with large and expensive radiation sources, such as 3[Formula: see text] generation synchrotrons. Especially in medicine, this limitation prevents various promising developments in imaging and therapy from being translated into clinical practice. Here we present a new concept of highly brilliant x-ray sources, li...

PURPOSE Meaningful errors in photocoagulation spot size may result from several factors. In this article we discuss one major factor, namely, fluctuations in the surgeon's accommodative state, coupled with an inaccurate setting of the slit-lamp oculars. DESIGN Experimental study. METHODS We analyzed and tested the optics of slit-lamp mounted lasers. Varying the ocular setting is correlated ...

In another contribution we presented numerical simulation results of LAPLAS implosion [1] that uses an annular beam focal spot to drive the target. In the present contribution we report similar results that have been achieved using a circular focal spot. The rest of the beam parameters and the target parameters are the same as in the other case. The transverse intensity distribution in the foca...

Direct laser writing (DLW) enables arbitrary three-dimensional nanofabrication. However, the diffraction limit poses a major obstacle for realizing nanometer-scale features. Furthermore, it is challenging to improve fabrication efficiency using currently prevalent single-focal-spot systems, which cannot perform high-throughput lithography. To overcome these challenges, parallel peripheral-photo...

this paper describes day-one beamlines of the iranian light source facility and design concept of powder diffraction and spectromicroscopy beamlines as the most priorities of each synchrotron that cover the research requirements in the fields of physics, chemistry, nano-science, etc. for powder diffraction beamline energy range is 6-30 kev, resolution: 10-4, flux: 1012(ph/s/0.1%b.w.) and spot s...

We use a broadband microbolometer array to measure the full three-dimensional (3D) terahertz (THz) intensity profile emitted from a twocolor femtosecond plasma and subsequently focused in a geometry useful for nonlinear spectroscopic investigations. Away from the immediate focal region we observe a sharp, conical intensity profile resembling a donut, and in the focal region the beam collapses t...

Background: Benign pigmented lesions, including freckles, are common and various treatment modalities including lasers and peeling have been evaluated for their effectiveness in their treatment. Objective: To compare the clinical effects of focal peeling with Trichloroacetic Acid (TCA) and Nd:YAG (532 nm) laser on freckles. Methods: Twenty patients with freckles were treated with focal peeling ...

OBJECTIVE To evaluate the results of thermotherapy for retinoblastoma. DESIGN Prospective, nonrandomized analysis of the treatment method. PARTICIPANTS A total of 188 retinoblastomas in 80 eyes of 58 patients who were treated with thermotherapy. MAIN OUTCOME MEASURES Tumor response and ocular adverse effects. RESULTS Of 188 retinoblastomas treated with thermotherapy, mean tumor base was...

The propagation of short, intense laser pulses in the atmosphere is investigated theoretically and numerically. A set of three-dimensional (3D), nonlinear propagation equations is derived, which includes the effects of dispersion, nonlinear self-focusing, stimulated molecular Raman scattering, multiphoton and tunneling ionization, energy depletion due to ionization, relativistic focusing, and p...