Experimental study of harmonic generation from solid surfaces irradiated by multipicosecond laser pulses

Abstract

An experimental study is presented on harmonic generation from solid surfaces using 27 ps Nd:glass laser pulses (lambda=1053 nm) in the intensity range of 10(13)-10(15) W cm(-2). Second, third, and fourth harmonics emitted in the specular reflection direction showed intensity scaling exponents of 1.5, 1.8, and 3.8 for an obliquely incident p-polarized laser beam, providing a conversion efficiency of 2x10(-8), 10(-10), and 5x10(-12) at 10(15) W cm(-2), respectively. Second and third harmonic radiation generated using an s-polarized pump was about 10 and 100 times smaller, respectively, compared to that for the p-polarized laser radiation. Faraday rotation observed in the reflected fundamental radiation can explain the relative harmonic yields for the p and s polarizations of the pump beam.

X-ray Lasers, Plasma Properties and Harmonic Generation from Surfaces

“…It was observed that harmonics were generated by both p-and s-polarizations of laser in non-relativistic limit, contradictory to the theoretical expectation. The observed anomaly was explained in terms of the role of Faraday rotation of laser polarization through self-generated magnetic field in plasma [30].…”

“…Norreys et al [29] have observed harmonic emission up-to 75th order with a 1,053 nm, 2.5 ps Nd:glass laser. Ganeev et al [30] have observed high-order harmonic emission from the solid surfaces using 27 ps Nd:glass laser pulses. It was observed that harmonics were generated by both p-and s-polarizations of laser in non-relativistic limit, contradictory to the theoretical expectation.…”

“…The laser pulse duration is an important parameter, which governs the mechanism and the dynamics of the processes involved in harmonic generation. In this subsection we present the studies of low-order harmonic generation using picosecond [30] and femtosecond [36] pulses.…”

Enhanced resonant second harmonic generation in plasma based on density transition

“…Schifano et al [17] have observed the second harmonic generation from preformed plasma as a valuable diagnostic for fi lamentation under various interaction conditions. Ganeev et al [18] have presented experimental study on harmonic generation from solid surface irradiated by short laser pulses. The relative harmonic yield for the P and S polarization of the pump wave and their scaling with laser intensity are discussed.…”

Optimization of C5+ Balmer-α line intensity at 182 Å from laser-produced carbon plasma

“…At this laser intensity, the space resolved measurements show that the spectral intensity of this line peaks at ∼1.5 mm from the target surface indicating the maximum population of C 5+ ions (n = 3), at this distance. From a comparison of spatial intensity variation of this line with that of C 5+ Ly-α (n = 2 → 1) line, it is inferred that n = 3 state of C 5+ ions is predominantly populated through three-body recombination pumping of C 6+ ions of the expanding plasma consistent with quantitative estimates on recombination rates of different processes.Intense xuv soft X-ray radiation from pulsed laser plasma sources is of current interest for a variety of research investigations and technological applications [1][2][3][4][5]. Measurements of xuv radiation spectrum of laser-produced plasmas with high spectral, temporal and spatial resolutions is an essential part of many studies of laser plasma interaction, particularly for investigations of xuv soft X-ray lasing schemes [6].…”