Effects of excitation laser wavelength on Ly-α and He-α line emission from nitrogen plasmas

Abstract

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 spectral lines are 40-60 eV and 80-100 eV, respectively. The WW line emission and the conversion efficiency (CE) are estimated for three distinct Nd:YAG laser wavelengths (1064 nm, 532 nm, and 266 nm). The calculated CEs are compared with experimentally observed CE values. It is found that 1064 nm wavelength provides the highest CE from laser to Ly-α and He-α radiation.

Emission features and expansion dynamics of nanosecond laser ablation plumes at different ambient pressures

“…Some of the prominent applications of LPP include Pulsed laser deposition (PLD), 1 laser-ablation inductively coupled-plasma mass spectrometry (LA-ICP-MS), 2 laser-induced breakdown spectroscopy (LIBS), 3 nano-particles generation, 4 ion source, 5 and table top shorter wavelength light sources for lithography and microscopy. 6,7 Typically LPPs expand adiabatically and freely into vacuum; however, the presence of an ambient atmosphere modifies the entire process of plasma generation and hydrodynamic expansion. For example, the nature and pressure of an ambient gas greatly influence the energy coupling to the target, the laser-plasma coupling, and determine the hydrodynamic expansion features, cooling, and characteristic parameters (electron density, temperature) of the plume.…”

Expansion dynamics of ultrafast laser produced plasmas in the presence of ambient argon

“…Some of the key applications are pulsed laser deposition (PLD), 1 nanoparticle, nanostructure and cluster formation, 2,3 laser induced breakdown spectroscopy (LIBS), 4,5 LA inductively coupled plasma mass spectrometry (LA-ICP-MS) 6 and light sources for lithography, 7 and microscopy. 8 Understanding plasma plume dynamics is important for optimizing LPPs for all of these applications. The evolution of the plasma plume is highly transient in nature and is influenced by laser (wavelength, pulse duration, intensity, and spot size) and target (density, thermal properties, and geometry) parameters.…”

Kinetics of ion and prompt electron emission from laser-produced plasma

“…LA and resulting plasma formation has wide spread applications such as pulsed laser deposition (PLD), 1 laser induced breakdown spectroscopy (LIBS), 2,3 laser-ablation inductively coupledplasma mass spectrometry (LA-ICP-MS), 4 nano-particles generation, 5 laser ion source, 6,7 and table top shorter wavelength light sources for lithography 8 and microscopy. 9 However, even though LA is used for various applications, the physical parameters of laser ablation plumes vary widely with each application. The most important parameters that influence LA properties include laser wavelength, pulse width, spot size, and laser intensity.…”