High-order harmonic generation from metal plasmas using 1 kHz laser pulses

High-order harmonic generation in laser-produced plasma was demonstrated on metal surfaces using a high pulse repetition rate laser (1 kHz). It was found that if sufficiently thick bulk targets were used thermal conduction was sufficient to prevent any deterioration in the metal plasma plume production at this repetition rate. Under appropriate conditions harmonic yields were found to remain stable for >105 laser shots without the need to move the target. The high repetition rate allowed both short and long electron trajectories to be clearly identified during harmonic generation from the metal plasmas. © 2011 Taylor & Francis.This research was supported by a Marie Curie International Incoming Fellowship within the 7th European Community Framework Programme, EPSRC programme (Grant EP/ E028063/1), and FASTQUAST ITN. M.E. Lo´pez-Arias acknowledges CSIC for a JAE-pre contract.Peer Reviewe

Ablation of nanoparticles and efficient harmonic generation using a 1-kHz laser

We report on high-order-harmonic generation in nanoparticle-containing laser ablation plasmas using a Ti:sapphire driving laser at a repetition rate of 1 kHz and on the relation of the harmonic signals with the morphological and spectroscopic characteristics of the ablation deposits. The study of the deposits has allowed the definition of ablation conditions, leading to the generation of a plasma containing nanoparticles of similar sizes to the ones used as target material. The corresponding plasma plumes lead to efficient conversion of the IR photons towards the short-wavelength range through high-order harmonic generation and show superior performance to those corresponding to bulk targets of the same metallic element. © 2013 American Physical Society.Peer Reviewe

Identification of predominant Ferric Signatures in Association to the Martian Sulfate Deposits

International audienc

Comparative studies of resonance enhancement of harmonic radiation in indium plasma using multicycle and few-cycle pulses

Enhanced single harmonic generation is analyzed in indium laser ablation plasmas at excitation conditions of multicycle (30 fs) and few-cycle (3.5 fs) pulses. We demonstrate the strong influence of pulse duration, on the emission spectra from the indium plasma. For few-cycle pulses, the enhanced emissions do not coincide with the expected harmonic wavelengths, which is the case for multicycle pulses. We test the coherent properties of an enhanced emission around 20 eV using polarization and double-slit interference techniques. We also characterize the dynamics of the emissions from the indium plasma by tuning the laser pulse duration. A theoretical analysis is presented to describe the indium plasma emission upon excitation by few-cycle pulses. © 2013 American Physical Society.Peer Reviewe

Harmonic Generation in Laser Ablation Plasmas of Nucleobases

Trabajo presentado en la 12th Conference on Laser Ablation, celebrada en Nápoles (Italia) del 06 al 11 de octubre de 2013.The possibility of using DNA-based materials in photonics and nanoelectronics has stimulated the measurement and interpretation of their nonlinear optical properties [1]. Low-order harmonic generation (HG) of a driving laser propagating through an ablation plume has been proposed as a novel diagnosis technique for spatial and temporal exploration of the expanding plasma [2]. On the other hand, the use of plasma plumes has increased the number of materials available for efficient high harmonic generation (HHG), leading to discovery of new features of high-order harmonic spectroscopy [3]. In this work, we report on HG and HHG on nanosecond laser ablation plasmas of the nucleobases thymine (T) and uracil (U). Relations between the nonlinear response of the plasmas and their composition and dynamics are investigated by measuring the harmonics of an infrared nanosecond driving laser and the optical emission and time-of-flight mass spectra of the ablation plumes of targets consisting of pressed pellets of T and U

Characterization of laser-induced plasmas of nucleobases: Uracil and thymine

In this work, nanosecond laser ablation plasmas generated at 266 and 1064 nm of the two pyrimidine nucleobases uracil and thymine were characterized using time-of-flight mass spectrometry, optical emission spectroscopy and temporally resolved third harmonic generation of a probe laser. This multiple technique approach provides insight into the role played by the irradiation wavelength on the composition and dynamics of plasma species and on the differences between the laser plasmas of the two nucleobases.Peer Reviewe