Enhancement of the spontaneous emission in subwavelength quasi-two-dimensional waveguides and resonators

Abstract

We consider a quantum-electrodynamic problem of the spontaneous emission from a twodimensional (2D) emitter, such as a quantum well or a 2D semiconductor, placed in a quasi-2D waveguide or cavity with subwavelength confinement in one direction. We apply the Heisenberg-Langevin approach which includes dissipation and fluctuations in the electron ensemble and in the electromagnetic field of a cavity on equal footing. The Langevin noise operators that we introduce do not depend on any particular model of dissipative reservoir and can be applied to any dissipation mechanism. Moreover, our approach is applicable to nonequilibrium electron systems, e.g. in the presence of pumping, beyond the applicability of the standard fluctuation-dissipation theorem. We derive analytic results for simple but practically important geometries: strip lines and rectangular cavities. Our results show that a significant enhancement of the spontaneous emission, by a factor of order 100 or higher, is possible for quantum wells and other 2D emitters in a subwavelength cavity.

Magnetic dipole absorption of light at intersubband transitions in quantum wells

“…This expression differs from the well-known solution for a two-level system [4]. First, there is a factor 𝑑 𝑚𝑛 (𝑒𝑓𝑓) 𝐷 ̃𝑧 instead of 𝑑 𝑛𝑚 𝐸 ̃𝑧 which is due to possible inhomogeneity of the dielectric permittivity into QW [7]. Second, there is a new term Ω 𝑚𝑛 (𝜑) in the denominatorso-called "depolarization shift" of the resonant frequency relative to the intersubband transition frequency [25].…”

“…Let us define the potential well for electrons as 𝑈 𝑞𝑤 (𝑧) and use the simplest model for the electron Hamiltonian assuming that the energy gap between the valence and conduction bands is enough large [1,7]:…”

Enhanced emission from a single quantum dot in a microdisk at a deterministic diabolical point

“…Therefore, to estimate the potentials of this control method, we calculate optimal Purcell factors in microdisks with different R cut and two different β based on Q factors of our fabricated and ideal microdisks. Here we assume the QD is positioned at the maximum mode field of one cavity mode and the exciton dipole in the QD is parallel to the local mode electric field with much narrower linewidth than that of the cavity mode [47]. Then the optimal Purcell factor is given by[1]…”

Generation and dynamics of entangled fermion–photon–phonon states in nanocavities

“…5is true for any fields satisfying Maxwell's equations as long as intracavity losses can be neglected and the flux of the Poynting vector through the total cavity surface is zero (see e.g., Refs. [33][34][35][36]). Of course the photon losses are always important when calculating the decoherence rates and fluctuations.…”