Controlling the Spontaneous Emission Rate of Single Quantum Dots in a Two-Dimensional Photonic Crystal

Abstract

We observe large spontaneous emission rate modification of individual InAs Quantum Dots (QDs) in 2D a photonic crystal with a modified, high-Q single defect cavity. Compared to QDs in bulk semiconductor, QDs that are resonant with the cavity show an emission rate increase by up to a factor of 8. In contrast, off-resonant QDs indicate up to five-fold rate quenching as the local density of optical states (LDOS) is diminished in the photonic crystal. In both cases we demonstrate photon antibunching, showing that the structure represents an on-demand single photon source with pulse duration from 210 ps to 8 ns. We explain the suppression of QD emission rate using Finite Difference Time Domain (FDTD) simulations and find good agreement with experiment.One of the core issues of modern optics is the subject of photon interaction with matter. In the Wigner-Weisskopf approximation, the emission rate is directly proportional to the LDOS [1]. Over the past decade, photonic resonators with increased LDOS have been exploited to enhance emission rate for improving numerous quantum optical devices (e.g., [2,3]). Single photon sources in particular promise to see large improvements [4]. While more attention has been given to increasing emission rate, the reverse is also possible in an environment with decreased LDOS.Here we demonstrate that by designing a photonic crystal structure with a modified single-defect cavity, we can significantly increase or decrease the spontaneous emission (SE) rate of embedded QDs. Photonic crystals (PCs), periodic arrays of alternating refractive index, are near-ideal testbeds for such experiments. Their electromagnetic band structure modifies the LDOS relative to free space and hence the SE rate of embedded QD emitters. We demonstrate that SE of cavity-coupled QDs is enhanced up to 8 times compared to QDs in bulk GaAs. This coupling paves the way to single photon sources with higher out-coupling efficiency and visibility. On the other hand, decoupled QDs emit at up to five-fold decreased rate compared to bulk. This lifetime enhancement is significantly higher than

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Two-Photon Interference from the Far-Field Emission of Chip-Integrated Cavity-Coupled Emitters

“…[22][23][24][25] Emitters coupled to cavities can also serve as highly nonlinear devices operating at low photon numbers, 26 as well as efficient interfaces between photons and solid-state quantum memory. 27,28 The majority of the work to-date focused on a single emitter in a cavity, which can exhibit nearly perfect single photon purity and indistinguishability using resonant pumping techniques.…”

Directed self‐assembly of single quantum dots for telecommunication wavelength optical devices

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