Intersubband cavity polaritons: The role of higher photonic modes

Abstract

We present a theoretical analysis of the consequence of coupling between higher photonic modes and intersubband excitations in microcavities with embedded multiple quantum wells ͑MQWs͒. The polariton dispersion relations and angle-resolved absorption spectra are calculated numerically using a semiclassical approach based on a transfer-matrix formulation and effective-medium approximation. The obtained results are interpreted employing a multiple coupled harmonic-oscillator model supplemented by the input-output formalism. We show that when the MQW occupies a large fraction of space between cavity mirrors the coupling with higher photonic modes cannot be considered as a negligibly small perturbation in formation of the intersubband cavity polariton modes. When appropriate conditions are fulfilled the coupling between higher photonic modes and so-called "dark" intersubband electronic excitations can lead, in accordance with experimental results, to the formation of complex multiple-peaked absorption spectra.

Microcavity effect on the nonlinear intersubband response of multiple-quantum-well structures: The strong-coupling-regime

“…5 The system is grown on a GaAs semi-insulating substrate ͑ s = GaAs ͒ and consists of: Fig. 1͒ and A ͑see Fig.…”

“…Note that when is very close to res then the lower polariton branches, associated with higher photonic modes ͑n Ͼ 1͒, are closely spaced slightly below IT . 5 The above mentioned modes are responsible for the appearance of the small central peak in the angle-resolved absorption spectra reported by Dupont et al 1,2 ͓The spatial distribution profile of ͉H y ͉ arising from an incident field with Х −n Ј and = res ͑not presented here͒ supports the above statement ͑see also Ref. 5͒.͔ It is interesting to note that in the presence of the inhomogeneous broadening, the formation of the additional central peak is possible also in the single cavity mode approximation.…”

“…5͒.͔ It is interesting to note that in the presence of the inhomogeneous broadening, the formation of the additional central peak is possible also in the single cavity mode approximation. 5,21 It is obvious that we can expect a substantial deviation from the linear absorption spectra in the limit of strong intensities of the incident light. A detailed inspection of the equations predicted by the FPM ͑see also Figs.…”

“…The strong-coupling-regime ͑SCR͒, in which the dipole coupling between intersubband excitation and the cavity photon gives rise to coherent mixed modes ͑intersubband cavity polaritons͒ has recently received a lot of attention from both experimentalists and theoreticians. [1][2][3][4][5] In view of applications for optoelectronic devices, the analysis of the nonlinear intersubband properties is a fundamental and intriguing field of MC physics.…”

Effective polariton-polariton interactions of cavity-embedded two-dimensional electron gases

“…In particular, they are the normal modes due to the strong coupling between a cavity photon mode and the transition between two conduction subbands in quantum wells containing a two-dimensional electron gas. Intersubband polaritons were experimentally demonstrated for the first time in 2003 1 and their physics is the object of many interesting investigations, both fundamental [2][3][4][5][6][7][8][9][10][11][12] and applied [13][14][15][16][17][18][19][20][21] . So far, theoretical investigations have been based mostly on a bosonized Hamiltonian approach 2 .…”