Here two theoretical models of semi-classical matrix and quantum Green's function are developed for the system of x-ray thin-film planar cavity with inner-shell electronic resonances. The semi-classical model is based on the matrix formalism to treat each layer as the propagating matrix. The crucial idea is to expand the propagating matrix of the resonant atomic layer under ultrathin-film approximation, then derive the analytical expression of the spectral observation, i.e, the cavity reflectance. The typical cavity effects of cavity enhanced decay rate, cavity induced energy shift and the Fano interference which were observed in the recent experiments could be phenomenologically interpreted. The second quantum model employs the analytical Green's function to solve the cavity system. The system Hamiltonian and the effective energy-level are derived. The effective energy-level scheme indicates that the cavity effect acts on the regulation of the intermediated core-hole state. To test the validity of the semi-classical matrix and quantum Green's function models, the classical Parratt's formalism and the dispersion correction of the atomic refractive index are also recalled. Very good agreements in reflectivity spectra between semi-classical and quantum models with the Parratt's results are observed. The present semi-classical matrix and quantum Green's function models will be useful to predict the new phenomena and optimize the cavity structures for future experiments and promote the emerging of quantum optical effects with modern x-ray spectroscopy techniques.
Emphasizing first the utility of the generalized Fresnel coefficients in the theory of the Casimir effect in planar cavities, we complement our previous discussion of the ordinary Casimir force on and the Casimir stress in a metal (plasma) slab in a planar cavity. We demonstrate strong dependence of the Casimir stress in a thin slab on properties of the bounding medium in the symmetric Lifshitz configuration. Contrary to this, the stress in a thick slab gradually becomes insensitive on external boundary conditions. We also consider the position dependence of the Casimir force on and stress in …
In contrast to the free-space evolution of an atom governed by a multi-mode interaction with the surrounding electromagnetic vacuum, the evolution of a cavity-QED system can be characterized by just three parameters, (i) atom-cavity coupling strength g, (ii) cavity relaxation rate κ, and (iii) atomic decay rate into the non-cavity modes γ. In the case of an atom inserted into a planar resonator with an input beam coupled from the outside, it has been shown by Koshino [Phys. Rev. A 73, 053814 (2006)] that these three parameters are determined not only by the atom and cavity characteristics, but…
We propose a scheme that can generate tunable optomechanically induced transparency in a hybrid piezooptomechanical cavity system. The system is composed of a high-quality planar distributed Bragg reflector cavity modified with an embedded Gaussian-shaped defect. Moreover, interdigitated transducers are fabricated on the surface of the cavity to generate surface acoustic waves. Under the actuation of the surface acoustic wave, the upper Bragg mirrors can be vibrated as a bulk acoustic resonator, and the distributed Bragg reflector cavity becomes a standard three-level optomechanical system. In…
We emphasize and demonstrate that, besides using the usual recursion relations involving successive layers, generalized Fresnel coefficients of a multilayer can equivalently be calculated using the recursion relations involving stacks of layers, as introduced some time ago [M. S. Tomas, Phys. Rev. A 51, 2545 (1995)]. Moreover, since the definition of the generalized Fresnel coefficients employed does not imply properties of the stacks, these nonstandard recursion relations can be used to calculate Fresnel coefficients not only for local systems but also for a general multilayer consisting of v…
We analyze the thermal Casimir-Polder potential experienced by a ground-state molecule in a planar cavity and investigate the prospects for using such a set-up for molecular guiding. The resonant atom-field interaction associated with this non-equilibrium situation manifests itself in oscillating, standing-wave components of the potential. While the respective potential wells are normally too shallow to be useful, they may be amplified by a highly reflecting cavity whose width equals a half-integer multiple of a particular molecular transition frequency. We find that with an ideal choice of mo…
We consider a planar optical cavity with its main axis oriented perpendicular to the earth's local gravity field. We examine the motion of a wavepacket of light trapped within the cavity spacer under the action of gravity. Within a relativistic framework, we find that the wavepacket initially at rest in terms of in-plane group velocity is accelerated by $g$ at early time in agreement the non-relativistic limit of free-fall. We show that this phenomenon is a manifestation of gravitational redshift, applied on photons at rest within the cavity.
We present a method to enact a deterministic, measurement-free, optically generated controlled-phase gate on two qubits defined by single electrons trapped in large-area quantum dots in a planar microcavity. This method is robust to optical quantum dot inhomogeneity, requires only a modest-$Q$ planar cavity, employs only a single laser pulse, and allows the integration of many entangled qubits on one semiconductor chip. We present the gate in the contexts of both adiabatic evolution and geometric phases, and calculate the degradation of performance in the presence of both spontaneous emission …
It has long been believed that core-hole lifetime (CHL) of an atom is an intrinsic physical property, and controlling it is significant yet is very hard. Here, CHL of the 2p state of W atom is manipulated experimentally through adjusting the emission rate of a resonant fluorescence channel with the assistance of an x-ray thin-film planar cavity. The emission rate is accelerated by a factor linearly proportional to the cavity field amplitude, that can be directly controlled by choosing different cavity modes or changing the angle offset in experiment. This experimental observation is in good ag…
We report a novel hemispherical micro-cavity that is comprised of a planar integrated semiconductor distributed Bragg reflector (DBR) mirror, and an external, concave micro-mirror having a radius of curvature $50\mathrm{μm}$. The integrated DBR mirror containing quantum dots (QD), is designed to locate the QDs at an antinode of the field in order to maximize the interaction between the QD and the cavity. The concave micro-mirror, with high-reflectivity over a large solid-angle, creates a diffraction-limited (sub-micron) mode-waist at the planar mirror, leading to a large coupling constant betw…
A technique is demonstrated which efficiently transfers light between a tapered standard single-mode optical fiber and a resonant mode of a high-Q photonic crystal cavity with mode volume less than a cubic wavelength in size. Cavity mode quality factors of 4.7 x 10^4 are measured, and a total fiber-to-cavity coupling efficiency of 44% is demonstrated.
A resistive coupling circuit is used to model the recently discovered dissipative coupling in a hybridized cavity photon-magnon system. With this model as a basis we have designed a planar cavity in which a controllable transition between level attraction and level repulsion can be achieved. This behaviour can be quantitatively understood using an LCR circuit model with a complex coupling strength. Our work therefore develops and verifies a circuit method to model level repulsion and level attraction and confirms the universality of dissipative coupling in the cavity photon-magnon system. The …
Spoof surface modes on nanostructured metallic surfaces are known to have tailorable dispersion dependent on the geometric characteristics of the periodic pattern. Here we examine the spoof plasmon dispersion on an isolated grating and a grating-planar mirror cavity configuration. The spoof polariton dispersion in the cavity is obtained using the scattering matrix approach, and the related differential modal density of states is introduced to obtain the mode dispersion and classify the cavity polariton modes. The grating-mirror cavity geometry is an example of periodically nanostructured metal…
We explore the many-body phases of a two-dimensional Bose-Einstein condensate with cavity-mediated dynamic spin-orbit coupling. By the help of two transverse non-interfering, counterpropagating pump lasers and a single standing-wave cavity mode, two degenerate Zeeman sub-levels of the quantum gas are Raman coupled in a double-$Λ$-configuration. Beyond a critical pump strength the cavity mode is populated via coherent superradiant Raman scattering from the two pump lasers, leading to the appearance of a dynamical spin-orbit coupling for the atoms. We identify three quantum phases with distinct …
We obtain expressions for the Casimir energy and force following an approach which may be applied to cavities made up of arbitrary materials. In the case of planar cavities we obtain the well known Lifshitz formula. The approach is easily generalizable to other geometries.
In the absence of time-reversal symmetry, the asymmetric parameter q of the Fano resonance is extended into the complex space, where its trajectory can be utilized to investigate the decoherence process. By embedding the ensemble of M$\ddot{\rm{o}}$ssbauer nuclei in the thin-film planar cavity in this work, the trajectories of asymmetric parameter q are studied via the collective effect of the nuclear ensemble, which is regulated by the nuclear abundance and angle offset. Due to the diverse controllable methods of the collective resonant strength, there are different straight lines and arc-sha…
We present a semiconductor master equation technique to study the input/output characteristics of coherent photon transport in a semiconductor waveguide-cavity system containing a single quantum dot. We use this approach to investigate the effects of photon propagation and anharmonic cavity-QED for various dot-cavity interaction strengths, including weakly-coupled, intermediately-coupled, and strongly-coupled regimes. We demonstrate that for mean photon numbers much less than 0.1, the commonly adopted weak excitation (single quantum) approximation breaks down, even in the weak coupling regime.…
The transmission of a probe field experiencing electromagnetically induced transparency and optical switching in an atomic medium enclosed in an optical cavity is investigated. Using a semiclassical input-output theory for the interaction between an ensemble of four-level atoms and three optical cavity fields coupled to the same spatial cavity mode, we derive the steady-state transmission spectra of the probe field and discuss the dynamics of the intracavity field buildup. The analytical and numerical results are in good agreement with recent experiments with ion Coulomb crystals [M. Albert et…
The quantum Rabi oscillations in a coherently driven quantum dot embedded in a high-Q doubly resonant semiconductor micro-cavity in the presence of a strong second-order nonlinear medium is investigated theoretically. It is shown that the second order nonlinearity effect the Rabi oscillations in a significant manner.
A quantum information processing scheme is proposed with semiconductor quantum dots located in a high-Q single mode QED cavity. The spin degrees of freedom of one excess conduction electron of the quantum dots are employed as qubits. Excitonic states, which can be produced ultrafastly with optical operation, are used as auxiliary states in the realization of quantum gates. We show how properly tailored ultrafast laser pulses and Pauli-blocking effects, can be used to achieve a universal encoded quantum computing.
In this letter, we investigate the dynamics of a single superconducting artificial atom capacitively coupled to a transmission line with a characteristic impedance comparable or larger than the quantum resistance. In this regime, microwaves are reflected from the atom also at frequencies far from the atom's transition frequency. Adding a single mirror in the transmission line then creates cavity modes between the atom and the mirror. Investigating the spontaneous emission from the atom, we then find Rabi oscillations, where the energy oscillates between the atom and one of the cavity modes.
We present detailed numerical simulations of semiclassical and quantum spectra of a cavity quantum electrodynamics system consisting of a single three-level atom in $Λ$-configuration with one of its transitions strongly interacting with a quantized cavity mode while the other is driven by a coherent classical field. After deriving the equations of motion for the expected values of the system operators from the master equation, we compute numerically the semiclassical and quantum spectra of the system under various levels of external driving field strengths. In the semiclassical approach we neg…
We have fabricated an atom chip device which combines the circuitry for magnetic trapping of cold atoms with high-finesse optical resonators suitable for cavity QED in the single-atom strong coupling regime. Fabry-Perot optical resonators with finesse F > 2 X 10^5 were formed between a micropatterned on-chip planar mirror with lateral dimension of < 100 um and a curved mirror suspended above the chip. The strong and rapid thermal coupling between on-chip electrical and optical elements was utilized to stabilize the cavity mirror separation with servo bandwidth exceeding 100 kHz during simulate…
The non-resonant interaction between the high-density excitons in a quantum well and a single mode cavity field is investigated. An analytical expression for the physical spectrum of the excitons is obtained. The spectral properties of the excitons, which are initially prepared in the number states or the superposed states of the two different number states by the resonant femtosecond pulse pumping experiment, are studied. Numerical study of the physical spectrum is carried out and a discussion of the detuning effect is presented.
We describe how quantum dot semiconductor cavity systems can be engineered to realize anisotropy-induced dipole-dipole coupling between orthogonal dipole states in a single quantum dot. Quantum dots in single-mode cavity structures as well as photonic crystal waveguides coupled to spin states or linearly polarized excitons are considered. We demonstrate pronounced dipole-dipole coupling to control the radiative decay rate of excitons and form pure entangled states in the long time limit. We investigate both field-free entanglement evolution and coherently pumped exciton regimes, and show how a…
We theoretically investigate polarization-entangled photon generation by using a semiconductor quantum dot embedded in a microcavity. The entangled states can be produced by the application of two cross-circularly polarized laser fields. The quantum dot nanostructure is considered as a four-level system (ground, two excitons and bi-exciton states) and the theoretical study relies on the dressed states scheme. The quantum correlations, reported in terms of the entanglement of formation, are extensively studied for several values of the important parameters of the quantum dot system as the bi-ex…
We propose a scheme to efficiently couple a single quantum dot electron spin to an optical nano-cavity, which enables us to simultaneously benefit from a cavity as an efficient photonic interface, as well as to perform high fidelity (nearly 100%) spin initialization and manipulation achievable in bulk semiconductors. Moreover, the presence of the cavity speeds up the spin initialization process beyond GHz.
We investigate the emission properties of a single semiconductor quantum dot deterministically coupled to a confined optical mode in the weak coupling regime. A strong pulling, broadening and narrowing of the cavity mode emission is evidenced when changing the spectral detuning between the emitter and the cavity. These features are theoretically accounted for by considering the phonon assisted emission of the quantum dot transition. These observations highlight a new situation for cavity quantum electrodynamics involving spectrally broad emitters.
We present a numerical study comparing semiclassical and quantum models of a damped, strongly interacting cavity QED system composed of a single two-level atom interacting with a single quantized cavity mode driven externally by a tunable monochromatic field. We compute the steady state transmission spectrum of the coupled system under each model and show that in the strong coupling regime, the two models yield starkly different results. The fully quantum mechanical model of the system correctly yields the expected multiphoton transmission spectra while the semiclassical approach results in a …
The pseudospin of heavy-holes (HHs) confined in a semiconductor quantum dot (QD) represents a promising candidate for a fast and robust qubit. While hole spin manipulation by a classical electric field utilizing the Dresselhaus spin-orbit interaction (SOI) has been demonstrated, our work explores cavity-based qubit manipulation and coupling schemes for inversion-symmetric crystals forming a planar HH QD. Choosing the exemplary material Germanium (Ge), we derive an effective cavity-mediated ground state spin coupling that harnesses the cubic Rashba SOI. In addition, we propose an optimal set of…
We present a simple extension of the semi-classical model for a two-level system in a cavity, in order to incorporate multiple polarized transitions, such as those appearing in neutral and charged quantum dots (QDs), and two nondegenerate linearly polarized cavity modes. We verify the model by exact quantum master equation calculations, and experimentally using a neutral QD in a polarization non-degenerate micro-cavity, in both cases we observe excellent agreement. Finally, the usefulness of this approach is demonstrated by optimizing a single-photon source based on polarization postselection,…
We present here precise measurement of the resonance frequency, lifetime and shape of confined acoustic modes in the tens of GHz regime in GaAs/AlAs superlattice planar and micropillar cavities at low temperature ($\sim 20\,\textrm{K}$). The subharmonic resonant pump-probe technique, where the repetition rate of the pump laser is tuned to a subharmonic of the cavity resonance to maximize the amplitude of the acoustic resonance, in combination with a Sagnac interferometer technique for high sensitivity ($\sim 10 \,\textrm{fm}$) to the surface displacement, has been used. The cavity fundamental …
While artificially fabricated patterned metasurfaces are providing paradigm-shifting optical components for classical light manipulation, strongly interacting, controllable, and deterministic quantum interfaces between light and matter in free space remain an outstanding challenge. Here we theoretically demonstrate how to achieve quantum control of both the electric and magnetic components of an incident single-photon pulse by engineering the collective response of a two-dimensional atomic array. High-fidelity absorption and storage in a long-lived subradiant state, and its subsequent retrieva…
We investigate pump-induced exciton inversion in a quantum-dot cavity system with continuous wave drive. Using a polaron-based master equation, we demonstrate excited-state populations above 0.9 for an InAs dot at a phonon bath temperature of 4K. In an exciton-driven system, the dominant mechanism is incoherent excitation from the phonon bath. For cavity driving, the mechanism is phonon-mediated switching between ground- and excited-state branches of the ladder of photon states, as quantum trajectory simulations clearly show. The exciton inversion as a function of detuning is found to be quali…
Light-matter interactions at the single particle level have generally been explored in the context of atomic, molecular, and optical physics. Recent advances motivated by quantum information science have made it possible to explore coherent interactions between photons trapped in superconducting cavities and superconducting qubits. Spins in semiconductors can have exceptionally long spin coherence times and can be isolated in silicon, the workhorse material of the semiconductor microelectronic industry. Here, we review recent advances in hybrid "super-semi" quantum systems that coherently coup…
Broadband homodyne detection of the light transmitted by a Fabry-Perot cavity containing a strongly-coupled $^{133}$Cs atom is used to probe the dynamic optical response in a regime where semiclassical theory predicts bistability but strong quantum corrections should apply. While quantum fluctuations destabilize true equilibrium bistability, our observations confirm the existence of metastable states with finite lifetimes and a hysteretic response is apparent when the optical drive is modulated on comparable timescales. Our experiment elucidates remnant semiclassical behavior in the attojoule …
We present a novel hybrid system where an optical cavity is integrated with a microfabricated planar-electrode ion trap. The trap electrodes produce a tunable periodic potential allowing the trapping of up to 50 separate ion chains spaced by 160 $μ$m along the cavity axis. Each chain can contain up to 20 individually addressable Yb\textsuperscript{+} ions coupled to the cavity mode. We demonstrate deterministic distribution of ions between the sites of the electrostatic periodic potential and control of the ion-cavity coupling. The measured strength of this coupling should allow access to the …
The strong coupling between an intersubband excitation in a quantum cascade structure and a photonic mode of a planar microcavity has been detected by angle-resolved photovoltaic measurements. A typical anticrossing behavior, with a vacuum-field Rabi splitting of 16 meV at 78K, has been measured, for an intersubband transition at 163 meV. These results show that the strong coupling regime between photons and intersubband excitations can be engineered in a quantum cascade opto-electronic device. They also demonstrate the possibility to perform angle-resolved mid-infrared photodetection and to d…
An efficient atom-photon-interface is a key requirement for the integration of solid-state emitters such as color centers in diamond into quantum technology applications. Just like other solid state emitters, however, their emission into free space is severely limited due to the high refractive index of the bulk host crystal. In this work, we present a planar optical antenna based on two silver mirrors coated on a thin single crystal diamond membrane, forming a planar Fabry-Pérot cavity that improves the photon extraction from single tin vacancy (SnV) centers as well as their coupling to an ex…
We study a disordered ensemble of quantum emitters collectively coupled to a lossless cavity mode. The latter is found to modify the localization properties of the "dark" eigenstates, which exhibit a character of being localized on multiple, noncontiguous sites. We denote such states as semi-localized and characterize them by means of standard localization measures. We show that those states can very efficiently contribute to coherent energy transport. Our paper underlines the important role of dark states in systems with strong light-matter coupling.
We study the quantum dynamics of the cavity optomechanical system formed by a Fabry-Perot cavity with a thin vibrating membrane at its center. We first derive the general multimode Hamiltonian describing the radiation pressure interaction between the cavity modes and the vibrational modes of the membrane. We then restrict the analysis to the standard case of a single cavity mode interacting with a single mechanical resonator and we determine to what extent optical absorption by the membrane hinder reaching a quantum regime for the cavity-membrane system. We show that membrane absorption does n…
Experimental quantum information processing with superconducting circuits is rapidly advancing, driven by innovation in two classes of devices, one involving planar micro-fabricated (2D) resonators, and the other involving machined three-dimensional (3D) cavities. We demonstrate that circuit quantum electrodynamics can be implemented in a multilayer superconducting structure that combines 2D and 3D advantages. We employ standard micro-fabrication techniques to pattern each layer, and rely on a vacuum gap between the layers to store the electromagnetic energy. Planar qubits are lithographically…
Chip-based cavity quantum electrodynamics (QED) devices consisting of a self-assembled InAs quantum dot (QD) coupled to a high quality factor GaAs microdisk cavity are coherently probed through their optical channel using a fiber taper waveguide. We highlight one particularly important aspect of this all-fiber measurement setup, which is the accuracy to which the optical coupling level and optical losses are known relative to typical free-space excitation techniques. This allows for precise knowledge of the intracavity photon number and measurement of absolute transmitted and reflected signals…
Near-concentric optical cavities of spherical mirrors can provide technical advantages over the conventional near-planar cavities in applications requiring strong atom-light interaction, as they concentrate light in a very small region of space. However, such cavities barely support stable optical modes, and thus impose practical challenges. Here, we present an experiment where we maintain a near-concentric cavity at its last resonant length for laser light at 780 nm resonant with an atomic transition. At this point, the spacing of two spherical mirror surfaces is 207(13) nm shorter than the c…
We evaluate the advantages of performing cross-phase modulation (XPM) on a very-far-off-resonance atomic system. We consider a ladder system with a weak (few-photon level) control coherent field imparting a conditional nonlinear phase shift on a probe beam. We find that by coupling to an optical resonator the optimal XPM is enhanced proportional to the finesse of the resonator by a factor of $F/4π$. We present a semi-classical description of the system and show that the phenomenon is optimal in the self-defined condition of off-resonance-effective-cooperativity equal to one.
