High order harmonic generation from intense laser irradiation of wavelength scale particles

This project is aimed at understanding the nonlinear optical properties of particles of sizes ranging from a few nm to a few µm in the strong field regime. We are particularly interested in high order harmonic generation from these spheres. (Tutorial) These studies are of interest not only because they elucidate the electron dynamics in these strong field interactions but also because such studies may lead to enhanced conversion efficiencies of laser light to short wavelength light, and therefore have a direct bearing on the development of coherent, ultrafast short wavelength sources. Such sources may have many applications.

We are using femtosecond laser pulses focused to intensity of 1010 - 1019 W/cm² to examine the nonlinear optical properties of clusters, droplets and small solid spheres. A variety of prepulse techniques will be employed in an attempt to control the Mie and giant dipole resonances that control the optical properties of such small particles. Ultimately, the experimental studies undertaken here will bridge the understanding between high harmonic generation in atomic media and harmonic generation at a solid (or plasma) surface.

The aim of this project is to study the conversion of the laser fundamental to near UV (second and third harmonic) light as well as very high order harmonic generation in the soft x-ray region when spheres and clusters are irradiated. We study various properties, like conversion efficiency, spectrum and spatial distribution.

To see some calculations on this, click here.

UT participants: Ariel Sumeruk (grad. student) Bong-hu Shim (grad. student) Kirk Madison (post-doc) Mike Downer (Prof.) Todd Ditmire (Prof.)

Some interesting papers related to this topic from our previous research:

T. D. Donnelly, M. Rust, I. Weiner, M. Allen, R. A. Smith, C. A. Steinke, S. Wilks, J. Zweiback, T. E. Cowan, and T. Ditmire, "Hard X-ray Production from Intense Laser Irradiation of Wavelength-Scale Particles" J. Phys. B: At. Mol. Opt. Phys. 34, L313 (2001). [PDF]

J. W. G. Tisch, T. Ditmire, D. J. Fraser, N. Hay, M. B. Mason, E. Springate J. P. Marangos, and M. H. R. Hutchinson, “Investigation of High-Harmonic Generation From Xenon Atom Clusters,” J. Phys. B: At. Mol. Opt. Phys.. 30, L709 (1997). [PDF]

J. W. G. Tisch, D. D. Meyerhofer, T. Ditmire, N. Hay, and M. H. R. Hutchinson, “Measurement of the Spatio-Temporal Evolution of High-Order Harmonic Radiation Using Chirped Pulse Spectroscopy,” Phys. Rev. Lett. 80, 1204 (1998). [PDF]

T. D. Donnelly, T. Ditmire, K. Neuman, M. D. Perry and R. W. Falcone, “High-Order Harmonic Generation in Atom Clusters,” Phys. Rev. Lett. 76, 2472 (1996). [PDF]