Aluminum nitride is a technologically important wide bandgap semiconductor which has been shown to host bright quantum emitters. In this paper, we probe the photodynamics of quantum emitters in aluminum nitride using photon emission correlations and time-resolved spectroscopy. We identify that each emitter contains as many as 6 internal energy levels with distinct laser power-dependent behaviors. Power-dependent shelving and de-shelving processes, such as optically induced ionization and recombination are considered, indicating complex optical dynamics associated with the spontaneous and optically pumped transitions. State population dynamics simulations qualitatively explain the temporal behaviours of the quantum emitters, revealing that those with pump-dependent de-shelving processes can saturate at significantly higher intensities, resulting in bright room-temperature quantum light emission.
Aluminum nitride is a technologically important wide bandgap semiconductor which has been shown to host bright quantum emitters. In this paper, we probe the photodynamics of quantum emitters in aluminum nitride using photon emission correlations and time-resolved spectroscopy. We identify that each emitter contains as many as 6 internal energy levels with distinct laser power-dependent behaviors. Power-dependent shelving and de-shelving processes, such as optically induced ionization and recombination are considered, indicating complex optical dynamics associated with the spontaneous and optically pumped transitions. State population dynamics simulations qualitatively explain the temporal behaviours of the quantum emitters, revealing that those with pump-dependent de-shelving processes can saturate at significantly higher intensities, resulting in bright room-temperature quantum light emission.
Aluminum nitride is a technologically important wide band-gap semiconductor which has been shown to host bright quantum emitters. We use photon emission correlation spectroscopy (PECS), time-resolved photoluminescence (TRPL), and state-population dynamic simulations to probe the dynamics of emission under continuous wave (CW) and pulsed optical excitation. We infer that there are at least four dark shelving states, which govern the TRPL, bunching, and saturation of the optical transition. We study in detail the emission dynamics of two quantum emitters (QEs) with differing power-dependent shelving processes, hypothesized to result from charge ionization and recombination. These results demonstrate that photon bunching caused by shelving the system in a dark state inherently limits the saturation rate of the photon source. In emitters where increasing optical power deshelves the dark states, we observe an increased photon emission intensity. Published by the American Physical Society 2024
Solid-state quantum emitters (QEs) are fundamental in photonic-based quantum information processing. There is strong interest to develop high-quality QEs in III-nitride semiconductors because of their sophisticated manufacturing driven by large and growing applications in optoelectronics, high voltage power transistors, and microwave amplifiers. Here, the generation and direct integration of QEs in an aluminum nitride-based photonic integrated circuit platform is reported. For individual waveguide-integrated QEs, an off-chip count rate exceeding 6 × 10 4 counts per second (cps; saturation rate >8.6 × 10 4 cps) is measured at room temperature under continuous-wave (CW) excitation. In an unpatterned thin-film sample, antibunching with g (2) (0) ∼ 0.08 and photon count rates exceeding 8 × 10 5 cps (saturation rate >1 × 10 6 cps) are measured at room temperature under CW excitation. Although spin and detailed optical line width measurements are left for future work, these results already show the potential for high-quality QEs monolithically integrated in a wide range of III-nitride device technologies that would enable new quantum device opportunities and industrial scalability.
Solid-state quantum emitters (QEs) are fundamental in photonic-based quantum information processing. There is strong interest to develop high-quality QEs in III-nitride semiconductors because of their sophisticated manufacturing driven by large and growing applications in optoelectronics, high voltage power transistors, and microwave amplifiers. Here, we report the generation and direct integration of QEs in an aluminium nitride-based photonic integrated circuit platform. For individual waveguide-integrated QEs, we measure an off-chip count rate exceeding 6×104 counts per second (cps) (saturation rate > 8.6×104 cps). In an unpatterned thin-film sample, we measure antibunching with g(2)(0)∼0.05 and photon count rates exceeding 8×105 cps (saturation rate > 1×106 cps). Although spin and detailed optical linewidth measurements are left for future work, these results already show the potential for high-quality QEs monolithically integrated in a wide range of III-nitride device technologies that would enable new quantum device opportunities and industrial scalability.
Photon emission correlation spectroscopy (PECS) is an indispensable tool for the study of atoms, molecules, and, more recently, solid-state quantum defects. In solid-state systems, its most common use is as an indicator of single-photon emission, a key property for quantum technology. Beyond single-photon purity, photon correlation measurements can provide a wealth of information that can reveal details about an emitter's electronic structure and optical dynamics that are hidden by other spectroscopy techniques. This thesis explores the application of PECS to study and understand the optical dynamics of quantum emitters. The first part of this thesis presents a guide to a standardized framework for using PECS to facilitate materials exploration for qubit candidates. This includes discussion of theoretical background, considerations for data acquisition and statistical analysis, and interpretation of PECS. It also illustrates how this experimental technique can be paired with optical dynamics simulations to formulate an electronic model for unknown quantum emitters. The second part of this thesis implements the practices discussed in the first part to explore the optical dynamics of two systems: the nitrogen-vacancy (NV) center in diamond and a quantum emitter in hexagonal boron nitride (h-BN). The NV center is a promising platform for applications in quantum sensing, quantum communication, and quantum networks. In particular, its spin and charge dynamics constitute useful attributes that can be harnessed for quantum control protocols. This thesis models and quantifies the transition rates that govern spin and charge dynamics in the NV center, utilizing PECS measurements, analysis, and simulations as a function of magnetic field, and excitation power. These findings can further inform the design of quantum control protocols. H-BN hosts pure single-photon emitters that have shown evidence of optically detected electronic spin dynamics. However, the electrical and chemical structure of these optically addressable spins is unknown, and the nature of their spin-optical interactions remains mysterious. This thesis discusses time-domain optical and microwave experiments to characterize a single emitter in h-BN exhibiting room temperature optically detected magnetic resonance. It further discusses use of dynamical simulations to constrain and quantify transition rates in the model, and design of optical control protocols that optimize the signal-to-noise ratio for spin readout. This constitutes a necessary step towards quantum control of spin states in h-BN.
Quantum emitters in solid-state crystals have recently attracted a great deal of attention due to their simple applicability in optical quantum technologies. The polarization of single photons generated by quantum emitters is one of the key parameters that plays a crucial role in various applications, such as quantum computation, which uses the indistinguishability of photons. However, the degree of single-photon polarization is typically quantified using the time-averaged photoluminescence intensity of single emitters, which provides limited information about the dipole properties in solids. In this work, we use single defects in hexagonal boron nitride and nanodiamond as efficient room-temperature single-photon sources to reveal the origin and temporal evolution of the dipole orientation in solid-state quantum emitters. The angles of the excitation and emission dipoles relative to the crystal axes were determined experimentally and then calculated using density functional theory, which resulted in characteristic angles for every specific defect that can be used as an efficient tool for defect identification and understanding their atomic structure. Moreover, the temporal polarization dynamics revealed a strongly modified linear polarization visibility that depends on the excited-state decay time of the individual excitation. This effect can potentially be traced back to the excitation of excess charges in the local crystal environment. Understanding such hidden time-dependent mechanisms can further improve the performance of polarization-sensitive experiments, particularly that for quantum communication with single-photon emitters.
Quantum emitters in solid-state crystals have recently attracted a lot of attention due to their simple applicability in optical quantum technologies. The polarization of single photons generated by quantum emitters is one of the key parameters that play a crucial role in the applications, such as quantum computation that uses the indistinguishability of photons. However, the degree of single photon polarization is typically quantified using time-averaged photoluminescence intensity of single emitters, which provides limited information about the dipole properties in solids. In this work, we use single defects in hexagonal boron nitride and nanodiamond as efficient room-temperature single photon sources to reveal the origin and the temporal evolution of dipole orientation in solid-state quantum emitters. The angle of excitation and emission dipoles relative to the crystal axes are determined experimentally and then calculated using density functional theory, which results in characteristic angles for every specific defect that can be used as an efficient tool for defect identification and understanding their atomic structure. Moreover, the temporal polarization dynamics reveal a strongly modified linear polarization visibility that depends on the excited state decay time of individual excitation. This effect can be traced back potentially to the excitation of excess charges in the local crystal environment. Understanding such hidden time-dependent mechanisms can further be used to improve the performance of polarization-sensitive experiments, in particular that of quantum communication with single photon emitters.