J. Abdul-Hadi

Intense multimicrojoule high-order harmonics generated from neutral atoms of In2O3 nanoparticles

We studied high-order harmonic generation from plasma that contains an abundance of indium oxide nanoparticles. We found that harmonics from nanoparticle-containing plasma are considerably more intense than from plasma produced on the In2O3 bulk target, with high-order harmonic energy ranging from 6 μJ (for the ninth harmonic) to 1 μJ (for the 17th harmonic) in the former case. The harmonic cutoff from nanoparticles was at the 21st order, which is lower than that observed using indium oxide solid target. By comparing the harmonic spectra obtained from solid and nanoparticle indium oxide targets, we concluded that intense harmonics in the latter case are dominantly generated from neutral atoms of the In2O3 nanoparticles.

Blueprint for generating intense attosecond pulses using high-order harmonics from graphitic carbon plasma

We report the generation of extremely efficient (>; 10-4), multi -μJ high -order harmonics from graphitic carbon plasma, which spans over five harmonic orders. This broad bandwidth is ideal for generating intense single-cycle attosecond pulses.

High-Order Harmonic Generation from Nanostructured Material Using the Laser-Plasma Method

We show that highly efficient harmonics in the extreme ultra-violet spectral range can be achieved by using various nanostructured materials, such as metal nanoparticles and fullerenes. Conversion efficiencies near 10− 4 have been achieved for harmonics from C60 fullerene plasma. Experimental results reveal that the extension of the harmonic cutoff is negligible for such nanostructured material. Harmonics generated from plasma containing an abundance of nanomaterials were between 5 and 12 times more intense than plasma abundant with monatomic particles, depending on the harmonic order and pump laser conditions. Since the intense harmonics disappear with ionization, we attribute these harmonics to contributions from neutral atoms within the nanostructured material. Experiments and calculations reveal that for C60 fullerenes, there is also contribution from their surface plasmon resonance centered at 20 eV.

Intense high-order harmonics from nanostructured material

We demonstrate highly efficient, multi-muJ high-order harmonic generation from plasma containing an abundance of nano-structured material, such as nanoparticles and fullerenes. We attribute this effect to harmonic generation from neutral atoms in such particles.

High-order harmonics from C 60 fullerenes -toward attosecond dynamics of complex systems

We demonstrate, for the first time, high-order harmonic generation from C<inf>60</inf> pumped by intense femtosecond Ti: sapphire laser. Laser-produced plasmas from C<inf>60</inf>-rich epoxy and C<inf>60</inf> films were used as the nonlinear media. Harmonics up to the 25^th order were observed. The harmonic yield from fullerene-rich plasma is about 25 times larger compared with those produced from bulk carbon target.

High-Intensity High-order Harmonics Generated from Low-Density Plasma

We study the generation of high‐order harmonics from lowly ionized plasma, using the 10 TW, 10 Hz laser of the Advanced Laser Light Source (ALLS). We perform detailed studies on the enhancement of a single order of the high‐order harmonic spectrum generated in plasma using the fundamental and second harmonic of the ALLS beam line. We observe quasi‐monochromatic harmonics for various targets, including Mn, Cr, Sn, and In. We identify most of the ionic/neutral transitions responsible for the enhancement, which all have strong oscillator strengths. We demonstrate intensity enhancements of the 13th, 17th, 29th, and 33rd harmonics from these targets using the 800 nm pump laser and varying its chirp. We also characterized the attosecond nature of such plasma harmonics, measuring attosecond pulse trains with 360 as duration for chromium plasma, using the technique of “Reconstruction of Attosecond Beating by Interference of Two‐photon Transitions” (RABBIT). These results show that plasma harmonics are intense sou...

High-order harmonic generation from fullerene plasma

We demonstrate high-order harmonic generation from C60 fullerenes pumped by intense Ti:sapphire laser. We observe a 25 times increase in the harmonic yield compared with bulk carbon, near the 22 eV giant resonance of C60.

High-order harmonics from targets containing an abundance of metal nanoparticles

We generate high-order harmonics from ablation plasma containing an abundance of nanoparticles. Results show that the use of nanoparticles targets enhances the harmonic intensity, and also shifts the harmonic spectrum in wavelength.