Photonic quantum networks frequently demand a consistent and reliable source for generating single photons and entangled photon pairs, which function as quintessential encoders of quantum information. However, many experiments demonstrating quantum algorithms using photons have necessarily been performed at cryogenic temperatures (milli to a few Kelvin), in order to mitigate the adverse effects of temperature dephasing. Encouraged by the relatively long lifetimes of group-N color centers, we show that subdiffracted heating produced by a near-field plasmonic transducer can control the resonant behavior of individual quantum emitters and, consequently, their emission. Our theoretical analysis establishes the ability to control antibunching and superbunching effects at elevated temperatures via highly manipulable, thermally-induced strain fields. Furthermore, our work raises encouraging prospects for the application of color centers in on-chip quantum photonics, while elevating technologies for solid-state quantum information processing towards ever higher temperatures.
Photonic quantum networks frequently demand a consistent and reliable source for generating single photons and entangled photon pairs, which function as quintessential encoders of quantum information. However, many experiments demonstrating quantum algorithms using photons have necessarily been performed at cryogenic temperatures (milli to a few Kelvin), in order to mitigate the adverse effects of temperature dephasing. Encouraged by the relatively long lifetimes of group-N color centers, we show that subdiffracted heating produced by a near-field plasmonic transducer can control the resonant behavior of individual quantum emitters and, consequently, their emission. Our theoretical analysis establishes the ability to control antibunching and superbunching effects at elevated temperatures via highly manipulable, thermally-induced strain fields. Furthermore, our work raises encouraging prospects for the application of color centers in on-chip quantum photonics, while elevating technologies for solid-state quantum information processing towards ever higher temperatures.
Temperature fluctuations in materials used for quantum networks can give rise to lattice vibrations that detune, dephase, and decrease the lifetimes of embedded quantum defects that function as qubits. Most experiments demonstrating quantum operations have been performed at cryogenic temperatures ranging from milli- to a few kelvin, thereby reducing these adverse effects. However, encouraged by the relatively long lifetimes recently discovered for group IV color centers, we aim to show that subdiffracted heating, i.e., nanoscale thermal "hot spots", produced by a plasmonic transducer can control the resonant behavior of individual qubits. Our analysis, reported over largely unexplored physical dimensions for the nanoheating of qubits, establishes the ability to perform dynamic quantum operations at elevated temperatures via thermally mediated control of two-photon coherence and subsequent photon-number entanglement. As such, color centers raise encouraging prospects for advancing on-chip quantum photonics and elevating solid-state quantum information processing technologies toward higher temperatures.
Achieving dynamic and broadband control of superradiance and subradiance at elevated temperatures is central to quantum photonic technologies. Herein, we theoretically investigate near-field photonics combined with adiabatic and non-adiabatic time-varying media—created via temporal modulation of material properties—to dynamically generate and coherently manipulate quantum emission states, including single photons and photon pairs. Distinctively, this cavity-free near-field method operates effectively at practical temperatures (tens of Kelvin), circumventing traditional operational constraints. We initiate this approach by exploiting plasmonically coupled silicon carbide color centers, which are used as quantum emitters (QEs), with relatively long coherence lifetimes, enabling precise quantum state control before temperature-induced dephasing sets in. In particular, a hybrid plasmonic waveguide is used as the light delivery method, where its subdiffracted near-field generates nanoscale heating that effectively tunes the energies of color centers, via phonon occupation, on resonance with the near-field. Furthermore, we employ transparent conducting oxides, such as indium tin oxide, that may achieve significant refractive index modulation on the femto–picosecond timescales. The resulting behavior is that of a photonic time crystal (PTC) or an epsilon-near-zero (ENZ) material response, dependent on modulation times, and characterized by the amplification or increased absorption of light, respectively, where both enhance field localization around the embedded QEs and extend periods of super- or subradiance compared to static conditions. Our methodology significantly simplifies scalable quantum photonic integration, while advancing quantum memories and entanglement capabilities under accessible conditions.
Solid-state quantum emitters are in high demand for emerging technologies such as advanced sensing and quantum information processing. Generally, these emitters are not sufficiently bright for practical applications, and a promising solution consists in coupling them to plasmonic nanostructures. Plasmonic nanostructures support broadband modes, making it possible to speed up the fluorescence emission in room-temperature emitters by several orders of magnitude. However, one has not yet achieved such a fluorescence lifetime shortening without a substantial loss in emission efficiency, largely because of strong absorption in metals and emitter bleaching. Here, we demonstrate ultrabright single-photon emission from photostable nitrogen-vacancy (NV) centers in nanodiamonds coupled to plasmonic nanocavities made of low-loss single-crystalline silver. We observe a 70-fold difference between the average fluorescence lifetimes and a 90-fold increase in the average detected saturated intensity. The nanocavity-coupled NVs produce up to 35 million photon counts per second, several times more than the previously reported rates from room-temperature quantum emitters.
The ability to shape photon emission facilitates strong photon-mediated interactions between disparate physical systems, thereby enabling applications in quantum information processing, simulation and communication. Spectral control in solid state platforms such as color centers, rare earth ions, and quantum dots is particularly attractive for realizing such applications on-chip. Here we propose the use of frequency-modulated optical transitions for spectral engineering of single photon emission. Using a scatteringmatrix formalism, we find that a two-level system, when modulated faster than its optical lifetime, can be treated as a single-photon source with a widely reconfigurable photon spectrum that is amenable to standard numerical optimization techniques. To enable the experimental demonstration of this spectral control scheme, we investigate the Stark tuning properties of the silicon vacancy in silicon carbide, a color center with promise for optical quantum information processing technologies. We find that the silicon vacancy possesses excellent spectral stability and tuning characteristics, allowing us to probe its fast modulation regime, observe the theoretically-predicted two-photon correlations, and demonstrate spectral engineering. Our results suggest that frequency modulation is a powerful technique for the generation of new light states with unprecedented control over the spectral and temporal properties of single photons.
Abstract The ability to shape photon emission facilitates strong photon-mediated interactions between disparate physical systems, thereby enabling applications in quantum information processing, simulation and communication. Spectral control in solid state platforms such as color centers, rare earth ions, and quantum dots is particularly attractive for realizing such applications on-chip. Here we propose the use of frequency-modulated optical transitions for spectral engineering of single photon emission. Using a scattering-matrix formalism, we find that a two-level system, when modulated faster than its optical lifetime, can be treated as a single-photon source with a widely reconfigurable photon spectrum that is amenable to standard numerical optimization techniques. To enable the experimental demonstration of this spectral control scheme, we investigate the Stark tuning properties of the silicon vacancy in silicon carbide, a color center with promise for optical quantum information processing technologies. We find that the silicon vacancy possesses excellent spectral stability and tuning characteristics, allowing us to probe its fast modulation regime, observe the theoretically-predicted two-photon correlations, and demonstrate spectral engineering. Our results suggest that frequency modulation is a powerful technique for the generation of new light states with unprecedented control over the spectral and temporal properties of single photons.
For a quantum Internet, one needs reliable sources of entangled particles that are compatible with measurement techniques enabling time-dependent, quantum error correction. Ideally, they will be operable at room temperature with a manageable decoherence versus generation time. To accomplish this, we theoretically establish a scalable, plasmonically based archetype that uses quantum dots (QD) as quantum emitters, known for relatively low decoherence rates near room temperature, that are excited using subdiffracted light from a near-field transducer (NFT). NFTs are a developing technology that allow rasterization across arrays of qubits and remarkably generate enough power to strongly drive energy transitions on the nanoscale. This eases the fabrication of QD media, while efficiently controlling picosecond-scale dynamic entanglement of a multiqubit system that approaches maximum fidelity, along with fluctuation between tripartite and bipartite entanglement. Our strategy radically increases the scalability and accessibility of quantum information devices while permitting fault-tolerant quantum computing using time-repetition algorithms.