Berlin 2005 – scientific programme
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HL: Halbleiterphysik
HL 4: Quantenpunkte und -dr
ähte: Optische Eigenschaften I
HL 4.11: Talk
Friday, March 4, 2005, 13:15–13:30, TU P-N201
Investigation of the optical mode structure in pillar microcavities — •N. Baer1, J. Wiersig1, P. Gartner1, F. Jahnke1, M. Benyoucef2, S.M. Ulrich2, P. Michler2, and A. Forchel3 — 1Institute for Theoretical Physics, University of Bremen — 2University of Stuttgart — 3University of Würzburg
Due to the wide range of application a detailed understanding of the mode structure in microresonators is desirable. For planar structures, such as VCSELs, the often used 2×2 - transfer-matrix technique is sufficient to describe the experimental results. For pillar structures, however, the transverse confinement becomes essential and this simple approach is no longer applicable.
In a theory-experiment comparison we study the influence of the transverse mode confinement for decreasing pillar diameter on the emission properties of semiconductor quantum dots in micropillars [1]. The mode structure is determined from the solution of vector Maxwell equations for the 3d geometry. For pillar diameters large compared to the light wavelength, results of the mode spectrum obtained from a vectorial transfer-matrix approach [2] agree well with experiments. For smaller diameter the cavity quality is reduced due to less efficient confinement of the modes in the transverse direction. This effect cannot be accounted for in a transfer matrix approach and alternative methods, e.g., mode calculations based on Green’s functions techniques are needed. Results show a decreasing transverse mode confinement for smaller pillars diameter.
[1] Benyoucef et al., New J. Phys. 6, 91 2004
[2] D. Burak and R. Binder, IEEE J. Quantum Electron. 33, 1205 (1997)