Controlling the spontaneous emission rate of quantum wells in rolled-up hyperbolic metamaterials

Abstract

We experimentally demonstrate the enhancement of the spontaneous emission rate of GaAs quantum wells embedded in rolled-up metamaterials. We fabricate microtubes whose walls consist of alternating Ag and (In)(Al)GaAs layers with incorporated active GaAs quantum-well structures. By variation of the layer thickness ratio of the Ag and (In)(Al)GaAs layers we control the effective permittivity tensor of the metamaterial according to an effective medium approach. Thereby, we can design samples with elliptic or hyperbolic dispersion. Time-resolved low temperature photoluminescence spectroscopy supported by finite-difference time-domain simulations reveal a decrease of the quantum well's spontaneous emission lifetime in our metamaterials as a signature of the crossover from elliptic to hyperbolic dispersion.

Nonlocal Antenna Theory - Part I: Foundations

“…In other words, in momentum space, the only effective unknown is the frequency-momentum space electric field E(k, ω) while all other quantities can be determined based on this field variable via simple algebraic calculations. Moreover, using the Fourier gauge, only the momentum space vector potential A(k, ω) needs to be found by solving (24). Both (23) and (24) are in fact algebraic equations, allowing us to derive exact analytical expressions for the antenna radiation in nonlocal media as will be demonstrated later.…”

“…Periodic structures are examples of systems in which wave propagation analysis is fundamentally conducted in the spatial Fourier space, although in that case it is usually referred to as reciprocal space [18]. Some previous work on controlling the radiation emitted by sources embedded into metamaterials (MTMs) include [19][20][21][22][23][24], where most of the focus is on conventional metamaterials used to modify the emission characteristics o optical sources in metamaterials. However, all conventional metamaterials exhibit spatial dispersion so the subject of spatial dispersion has been taken up more explicitly in more recent works such as [25].…”

Exact Derivation of the Radiation Law of Antennas Embedded into Generic Nonlocal Metamaterials: A Momentum-Space Approach

“…Following the common convention in physics, we capture the dependence on k by the term momentum space since momentum p and the wavevector k are related to each other in quantum physics by mere constant (the de Broglie relation p = k). Some previous work on controlling the radiation emitted by sources embedding into metamaterials include [4]- [9], where most of the focus is on conventional metamaterials used to modify the emission characteristics o optical sources in metamaterials. However, all conventional metamaterials exhibit spatial dispersion so the subject has been taken into consideration in more recent works such as [10].…”

Self-Rolled Multilayer Metasurfaces

“…[33][34][35] Self-rolled metamaterials have also been explored, 36 mainly focused on hyperbolic multilayers, for example for subwavelength imaging 37,38 and emission enhancement in quantum emitters. 39 The concept of stacking nanostructured optical metasurfaces exploiting the self-rolling technique to create MLMs has only been roughly explored experimentally in a system involving uniformly porous metallic films, 40 and theoretically to enable three-dimensional photonic crystals. 41 However, the deterministic fabrication of distinct optical metasurfaces into a multilayer assembly has not yet been experimentally demonstrated.…”