Efficient X-ray generation from gold colloidal solutions

Koji Hatanaka; Matteo Porta; Frances Camille P. Masim; Wei-Hung Hsu; Mai Thanh Nguyen; Tetsu Yonezawa; Armandas Balcytis; Saulius Juodkazis

arXiv · 1604.07541

Efficient X-ray generation from gold colloidal solutions

Koji Hatanaka·Matteo Porta·Frances Camille P. Masim·Wei-Hung Hsu·Mai Thanh Nguyen·Tetsu Yonezawa·Armandas Balcytis·Saulius Juodkazis

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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.

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Koji Hatanaka, Matteo Porta, Frances Camille P. Masim, Wei-Hung Hsu, Mai Thanh Nguyen, Tetsu Yonezawa, Armandas Balcytis, Saulius Juodkazis. 2016-04-26. Efficient X-ray generation from gold colloidal solutions. https://arxiv.org/abs/1604.07541

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