Two-Photon Ionization of Silver Clusters

Authors: V. Paployan, K. Madoyan, A. Melikyan, H. Minassian

Abstract:

In this paper, we calculate the two-photon ionization (TPI) cross-section for pump-probe scheme in Ag neutral cluster. The pump photon energy is assumed to be close to the surface plasmon (SP) energy of cluster in dielectric media. Due to this choice, the pump wave excites collective oscillations of electrons-SP and the probe wave causes ionization of the cluster. Since the interband transition energy in Ag exceeds the SP resonance energy, the main contribution into the TPI comes from the latter. The advantage of Ag clusters as compared to the other noble metals is that the SP resonance in silver cluster is much sharper because of peculiarities of its dielectric function. The calculations are performed by separating the coordinates of electrons corresponding to the collective oscillations and the individual motion that allows taking into account the resonance contribution of excited SP oscillations. It is shown that the ionization cross section increases by two orders of magnitude if the energy of the pump photon matches the surface plasmon energy in the cluster.

Keywords: Resonance enhancement, silver clusters, surface plasmon, two-photon ionization.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1110245

References:

[1] G. Ramakrishna, O. Varnavsky, J. Kim, D. Lee, and T. Goodson, Quantum-Sized Gold Clusters as Efficient Two-Photon Absorbers. J. Am. Chem. Soc., vol. 130, pp. 5032—5038, Mar. 2008.
[2] S. K. Avetisyan, A. O. Melikyan, H. R Minassian. Polarization Dependence of Two-Photon Absorption in GaAs/Ga1-xAlxAs Quantum Well Structure. J. Appl. Phys. vol. 80, pp.301-303, Feb. 1996.
[3] I. E. Protsenko, A.V. Uskov, Photoemission from metal nanoparticles. Physics-Uspekhi, vol. 55, pp. 508–518, May 2012.
[4] J. G. Endriz, W. E. Spicer, Experimental Evidence for the Surface Photoelectric Effect in Aluminum. Phys. Rev. Lett. vol. 27, pp. 570-573, Aug. 1971.
[5] D. Bohm, D. Pines, A Collective Description of Electron Interactions: III. Coulomb Interactions in a Degenerate Electron Gas, Phys. Rev. vol. 92, pp. 609-625, Nov. 1953.
[6] U. Kreibig, M. Vollmer, Optical Properties of Metal Clusters (Springer, Berlin, 1995).
[7] J. D. Jackson, Classical Electrodynamics. John Wily &Sons, 1999.
[8] P. B. Johnson and R.W. Christy, Optical Constants of the Noble Metals. Phys. Rev. B vol. 6, pp.4370-4379, Dec.1972.
[9] P. Biagioni, M. Celebrano, M. Savoini et al. Dependence of the twophoton photoluminescence yield of gold nanostructures on the laser pulse duration. Phys. Rev. B vol. 80, pp. 045411/1-5, Jul. 2009.
[10] L. D. Landau and E. M. Lifshitz, Quantum Mechanics. Non-relativistic Theory. Pergamon Press, 1977.
[11] Reinhard, B. M.; Siu, M.; Agarwal, H.; Alivisatos, A. P.; Liphardt, J. Calibration of Dynamic Molecular Rulers Based on Plasmon Coupling between Gold Nanoparticles Nano Lett. vol. 5, pp. 2246-2252, Nov. 2005.
[12] G. Alameddin, J. Hunter, D. Cameron and M. M. Kappes, Electronic and geometric structure in silver clusters. Chem. Phys. Lett. vol. 192, pp.122-128, Apr. 1992.