Regensburg 2004 – scientific programme

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HL: Halbleiterphysik

HL 50: Quantenpunkte und -dr
ähte: Optische Eigenschaften III

HL 50.4: Talk

Friday, March 12, 2004, 11:45–12:00, H14

TE- and TM-polarization resolved spectroscopy under normal incidence — •M. Schardt¹, C. Dotzler¹, S. Malzer¹, J. Müller², G. Rurimo², S. Quabis², G. Leuchs², and G.H. Döhler¹ — ¹Institut für Technische Physik I — ²Institut für Optik, Universität Erlangen-Nürnberg, Germany

Normally, optical experiments performed under normal incidence on semiconductor structures with broken symmetry regarding the direction perpendicular to the surface (quantum wells and quantum dots, e.g.) yield information only about transitions involving in-plane (p_x- and p_y-) components of the hole wave functions, because of the in-plane (TE) polarization of the light. Transitions sensitive to the p_z components are interacting only with TM-polarized light. Recently it has been demonstrated that a radially polarized laser beam focused through a microscope objective with a high numerical aperture (NA ≥ 0.9) is perfectly polarized along the optical axis in its focus. The light is mostly TM polarized within the whole focus area. So far, experimental evidence of this feature has been limited to an indirect proof by comparing the resulting spot size and shape with the theoretical predictions [1]. We are now presenting an approach allowing for a direct proof of the TM polarization. It is based on photo current studies of heavy- and light-hole excitonic absorption in quantum wells and self-assembled dots embedded in pin diodes. At the same time, this approach represents a novel technique for polarization resolved spectroscopy.

[1] S. Quabis et al., Optics Communications 179 (2000) 1-7