A method, which utilizes the large difference in ionization potentials between successive ionization states of trace atoms, for injecting electrons into a laser-driven wakefield is presented. Here a mixture of helium and trace amounts of nitrogen gas was used. Electrons from the K shell of nitrogen were tunnel ionized near the peak of the laser pulse and were injected into and trapped by the wa...

The effect of nitrogen addition and laser fluence on the atomic structure of amorphous carbon films (a-C) synthesized by femtosecond pulsed laser deposition has been studied. The chemical bonding in the films was investigated by means of X-ray photoelectron (XPS) and Raman spectroscopies. XPS studies revealed a decrease in the sp3 bonded carbon sites and an associated increase in the N−sp2C bon...

Title of Document: STUDY OF THE FEMTOSECOND DYNAMICS AND SPECTROSCOPY OF LASER IONIZED PLASMAS. JJennifer Anne Elle, Doctor of Philosophy, 2015 Directed By: Professor Howard Milchberg Department of Physics Ultra-short laser pulses are used to ionize gas in different configurations and study the plasma and ionization dynamics. The variation in non-linear index of refraction as a function of time...

AIMS/BACKGROUND Recently a commercially available scanning laser Doppler flowmeter has been produced, which provides two dimensional maps of the retinal perfusion. The aim of the present study was to investigate the reproducibility and the sensitivity of these measurements. METHODS 16 healthy subjects were randomised to inhale different gas mixtures of oxygen and nitrogen in a double blind cr...

The capillary discharge soft X-ray laser is a promising scheme with its long capillary plasma column that is efficiently generated by the fast current pulse of about several 10s ns. In this study, the possibility of a recombination soft X-ray laser will be discussed in anticipation of realizing a 13.4 nm H-like N EUV laser. Evolution of EUV emission from nitrogen plasma with number density of 1...

The study of blast waves produced by intense lasers in gases is motivated by the desire to explore astrophysically relevant hydrodynamic phenomena in the laboratory. A systematic scan of laser produced blast waves was performed and the structure of blast waves was examined over a wide range of drive laser energy. Lasers with energies ranging from 10–1000 J illuminated a pin target in either xen...

Laser-produced nitrogen plasmas emitting radiation at 2.48 nm (Ly-α) and 2.88 nm (He-α) are considered potential efficient sources for water-window (WW) microscopy. The atomic and optical properties of nitrogen plasma and influence of the laser wavelength on the line emission in the WW range are investigated. It is found that the optimal temperatures for maximum emission from Ly-α and He-α spec...

A scheme for NH2 detection by means of laser-induced fluorescence (LIF) with excitation in the ultraviolet-blue regime around 385 nm, in particular using the second harmonic of a solid-state Alexandrite laser, is presented. This alternative provides interference-free detection with improved signal compared with previously employed concepts based on Nd:YAG and dye-laser excitation in the visible...