General application of continuous-wave (CW) laser irradiation modes in photodynamic therapy can cause thermal damage to normal tissues in addition to tumors. A new photodynamic laser therapy system using a pulse irradiation mode was optimized to reduce nonspecific thermal damage. In in vitro tissue specimens, tissue energy deposition rates were measured in three irradiation modes, CW, pulse, an...

a r t i c l e i n f o Keywords: LIBS Double pulse LIBS Plasma diagnostics LPP Dual-pulse (DP) laser-induced breakdown spectroscopy (LIBS) provides significant improvement in signal intensity as compared to conventional single-pulse LIBS. We investigated collinear DPLIBS experimental performance using various laser wavelength combinations employing 1064 nm, 532 nm, and 266 nm Nd:YAG lasers. In p...

In the present study, an ultrafine grained (UFG) 304L stainless steel with the average grain size of 300 nm was produced by a combination of cold rolling and annealing. Weldability of the UFG sample was studied by Nd: YAG laser welding under different welding conditions. Taguchi experimental design was used to optimize the effect of frequency, welding time, laser current and laser pulse duratio...

introdouction: dentinal hypersensitivity (dh) is one of the most painful chronic problems reported in dental offices. various methods have been applied for the treatment of dh. however, majority of them are either ineffective or last for a short period of time. it has been reported that lasers, particularly neodymium- doped: yttrium aluminum garnet laser (nd: yag), can be helpful in the treatme...

Laser-plasma interaction has been a widespread and popular field of research since the birth of the laser. It involves numerous interesting phenomena such as inertial confinement fusion; generation and acceleration of electron, positron, neutron, proton and ion particle beams; source of electro-magnetic radiation in the IR, visible, UV and x-ray range, just to mention some important application...

In a forced laser-wakefield accelerator experiment (Malka et al 2002 Science 298 1596) where the length of the pump laser pulse is a few plasma periods long, the leading edge of the laser pulse undergoes frequency downshifting and head erosion as the laser energy is transferred to the wake. Therefore, after some propagation distance, the group velocity of the leading edge of the pump pulse—and ...

This paper reports the development of a compact and portable actively Q-switched Nd:YAG laser and its applications in laser-induced breakdown spectroscopy (LIBS). The laser was end-pumped by a vertical-cavity surface-emitting laser (VCSEL). The cavity lases at a wavelength of 1064 nm and produced pulses of 16 ns with a maximum pulse energy of 12.9 mJ. The laser exhibits a reliable performance i...

Femtosecond laser ablation of silicon in air was studied and compared with nanosecond laser ablation at ultraviolet wavelength (266 nm). Laser ablation efficiency was studied by measuring crater depth as a function of pulse number. For the same number of laser pulses, the fs-ablated crater was about two times deeper than the ns-crater. The temperature and electron number density of the pulsed l...

Airborne laser scanning, often referred to as lidar or laser altimetry, is a remote sensing technique which measures the round-trip time of emitted laser pulses to determine the topography of the Earth’s surface. While the first commercially available airborne laser scanners recorded only the time of one backscattered pulse, state-of-the-art systems measure first and last pulse; some are able t...