Self-homodyne measurement of a dynamic Mollow triplet in the solid state

Abstract

The study of light-matter interaction at the quantum scale has been enabled by the cavity quantum electrodynamics (CQED) architecture, 1 in which a quantum two-level system strongly couples to a single cavity mode. Originally implemented with atoms in optical cavities, 2, 3 CQED effects are now also observed with artificial atoms in solid-state environments. 4-6Such realizations of these systems exhibit fast dynamics, which makes them attractive candidates for devices including modulators and sources in high-throughput communications. However, these systems possess large photon out-coupling rates that obscure any quantum behavior at large excitation powers. Here, we have utilised a self-homodyning 7 interferometric technique that fully employs the complex mode structure of our nanofabricated cavity [8][9][10] to observe a quantum phenomenon known as the dynamic Mollow triplet. 11We expect this interference to facilitate the development of arbitrary on-chip quantum state generators, thereby strongly influencing quantum lithography, metrology, and imaging.The crowning achievement of quantum optics has been to develop a complete theory for the phenomenon of resonant light scattering from a quantized matter system. Beyond providing closure to debates over the nature of light, this theory has enabled observations of uniquely quantum spectacles such as photon antibunching, 4,12 indistinguishable quantum interference, 5,13 and the Mollow triplet. 14, 15The addition of nanoscale resonators to the quantum scattering problem has provided a new frontier in our quest to mould the flow of light. 4-6Here, our reported innovation centres on the investigation of resonant light scattering from a quantum nonlinearity (quantum dot [QD]) strongly coupled to a photonic crystal [PC] cavity. This strong coupling allows for quantum-coherent energy exchange between the resonator's quantized light field and the QD's excitonic field, leading to the formation of light-matter entangled states known as polaritons. 16-18Evidence for the system's strong coupling is provided from the clean avoided-crossing spectra in Fig. 1a. The relative positions of the emission peaks are determined by the transient energies of the Jaynes-Cummings (JC) ladder 19 (Fig. 1b). As the two polaritonic peaks transition of the coupled QD-cavity system obtained when tuning the QD resonance through the cavity mode. By fitting profiles from these spectra, we extract the cavity energy decay rate κ = 2π · 15 GHz and the coherent coupling rate g = 2π · 11 GHz. b, Transient energies for climbing the JC-ladder rung by rung for the first, second and third rung as solid, dashed and dotted lines, respectively. Transitions from upper and lower polaritons are colour coded in red and blue, respectively. c,d, Spectra of the coupled QD-cavity system taken at a QD-cavity detuning of ∆σa = −85 pm and an excitation power of roughly 15 nW/nm, showing QD-like polaritonic emission (highlighted by grey box) on top of (c) a Lorentzian resonance and (d) a Fano resonance. In both cases, ...

Spectral asymmetries in the resonance fluorescence of two-level systems under pulsed excitation

“…However, under excitation by a short pulse, the RF spectrum can take on features which obscure or eliminate this characteristic spectrum, especially under off-resonant excitation. The pulsed RF spectrum has been studied theoretically in atomic systems [5][6][7][8][9][10], and more recently in QD-cavity systems for on-resonance excitation [11], where a dynamic spectrum has been observed in the presence of cavity coupling [12].In this Letter, we describe the unique features of pulsed * c.gustin@queensu.ca RF spectra in depth using a master equation approach, and explore the different effects under time-dependent excitation, which are of interest to emerging experimental studies of pulsed quantum optical systems. In particular, we separate both the coherent and incoherent spectra under pulsed excitation of a single TLS incorporating the dissipative processes of spontaneous emission and pure dephasing.…”

“…However, under excitation by a short pulse, the RF spectrum can take on features which obscure or eliminate this characteristic spectrum, especially under off-resonant excitation. The pulsed RF spectrum has been studied theoretically in atomic systems [5][6][7][8][9][10], and more recently in QD-cavity systems for on-resonance excitation [11], where a dynamic spectrum has been observed in the presence of cavity coupling [12].…”

Self-homodyne-enabled generation of indistinguishable photons

“…Here, the suppression results from destructive interference between the light scattered from the fundamental cavity mode and the continuum above-the-light-line modes, leading to Fano-like resonances [34]. This effect can be used to significantly suppress JC coherent scattering of the excitation laser in detuned QD-cavity systems and extract the incoherent spectrum [32]. To reach SHS, we optimized the excitation conditions (focus and polarisation) for the suppression of coherent scattering.…”

“…To simulate self-homodyne suppression (SHS), we replace A(t) → a(t) + α(t) in equation (1). Physically, α(t) is a slightly phase-and amplitude-shifted version of the incident laser pulse (originating from the continuum-mode scattering) [32].…”

“…Specifically, we show that this recentlydiscovered self-homodyne suppression (SHS) effect [32] can be used to interferometrically reject the coherent scattering off a dissipative Jaynes-Cummings system and isolate the non-classical component of the emitted light. While our experimental approach is tailored to phoarXiv:1512.05626v2 [cond-mat.mes-hall]…”