Efficient X-ray generation from gold colloidal solutions
Abstract
Hard X-ray generation for Au nanoparticle dispersion was systematically investigated for different particle diameters ranging from 10 to 100 nm with a narrow size distribution of +/- 2%. Scaling law of X-ray generation is close to a 6-photon process before the onset of saturation for excitation by 45 fs laser pulses with central wavelength of 800 nm. This is consistent with bulk plasmon excitation at wavelength ~ 138 nm. The longitudinal E-field component due to nanoparticle focusing is responsible for the excitation of the longitudinal bulk plasmon. The proposed analysis also explains X-ray emission from water breakdown via an electron solvation mechanism at ~6.2 eV. The most efficient emission of X-rays was observed for 40 +/- 10 nm diameter nanoparticles which also had the strongest UV extinction. X-ray emission was the most efficient when induced by pre-chirped 370 +/- 20 fs laser pulses and exhibited the highest intensity at a negative chirp.
Cite
@article{arxiv.1604.07541,
title = {Efficient X-ray generation from gold colloidal solutions},
author = {Koji Hatanaka and Matteo Porta and Frances Camille P. Masim and Wei-Hung Hsu and Mai Thanh Nguyen and Tetsu Yonezawa and Armandas Balcytis and Saulius Juodkazis},
journal= {arXiv preprint arXiv:1604.07541},
year = {2016}
}