Loss of antibunching

We describe some of the main external mechanisms that lead to a loss of antibunching, i.e., that spoil the character of a given quantum light to deliver its photons separated from each other. Namely, we consider contamination by noise, a time jitter in the photon detection, and the effect of frequency filtering (or detection with finite bandwidth). The formalism to describe time jitter is derived and connected to the already existing one for frequency filtering. The emission from a two-level system under both incoherent and coherent driving is taken as a particular case of special interest. The coherent case is further separated into its vanishing- (Heitler) and high- (Mollow) driving regimes. We provide analytical solutions which, in the case of filtering, reveal an unsuspected structure in the transitions from perfect antibunching to thermal (incoherent case) or uncorrelated (coherent case) emission. The experimental observations of these basic and fundamental transitions would provide additional compelling evidence of the correctness and importance of the theory of frequency-resolved photon correlations.We describe some of the main external mechanisms that lead to a loss of antibunching, i.e., that spoil the character of a given quantum light to deliver its photons separated from each other. Namely, we consider contamination by noise, a time jitter in the photon detection, and the effect of frequency filtering (or detection with finite bandwidth). The formalism to describe time jitter is derived and connected to the already existing one for frequency filtering. The emission from a two-level system under both incoherent and coherent driving is taken as a particular case of special interest. The coherent case is further separated into its vanishing- (Heitler) and high- (Mollow) driving regimes. We provide analytical solutions which, in the case of filtering, reveal an unsuspected structure in the transitions from perfect antibunching to thermal (incoherent case) or uncorrelated (coherent case) emission. The experimental observations of these basic and fundamental transitions would provide additional compelling evidence of the correctness and importance of the theory of frequency-resolved photon correlations.

arXiv:2108.03226Physical Review AFeb 28, 20220 citations

Suppressed antibunching via spectral filtering: An analytical study in the two-photon Mollow regime

Julian Schleibner, S. Bounouar, Max Strauß +3 more

Mollow physics in the two-photon regime shows interesting features such as versatile generation of highly correlated photon pairs, timely ordered and energy tunable. Here, we calculate analytically the power spectral density $S(\ensuremath{\omega})$ and the two-photon correlations ${g}^{(2)}(\ensuremath{\tau})$, which are essential to discuss and study such phenomena in the resonant-driven dressed-state regime. It is shown that there exist upper and lower bounds of the ${g}^{(2)}(\ensuremath{\tau})$ function for certain spectrally selected photon pairs. Recently reported experiments agree with the presented theory and thereby it is shown that the resonant-driven four-level system is an interesting source for steerable quantum light in quantum cascade setups. We furthermore discuss the unlikeliness of observing antibunching for the delay time $\ensuremath{\tau}=0$ in the exciton-biexciton correlation functions in such experiments, since antibunching stems from a coherent and in-phase superposition of different photon-emission events. Due to the occurring laser photon scattering, this coherent superposition state is easily disturbed and leads to correlation functions of ${g}^{(2)}(0)=1$ .Mollow physics in the two-photon regime shows interesting features such as versatile generation of highly correlated photon pairs, timely ordered and energy tunable. Here, we calculate analytically the power spectral density $S(\ensuremath{\omega})$ and the two-photon correlations ${g}^{(2)}(\ensuremath{\tau})$, which are essential to discuss and study such phenomena in the resonant-driven dressed-state regime. It is shown that there exist upper and lower bounds of the ${g}^{(2)}(\ensuremath{\tau})$ function for certain spectrally selected photon pairs. Recently reported experiments agree with the presented theory and thereby it is shown that the resonant-driven four-level system is an interesting source for steerable quantum light in quantum cascade setups. We furthermore discuss the unlikeliness of observing antibunching for the delay time $\ensuremath{\tau}=0$ in the exciton-biexciton correlation functions in such experiments, since antibunching stems from a coherent and in-phase superposition of different photon-emission events. Due to the occurring laser photon scattering, this coherent superposition state is easily disturbed and leads to correlation functions of ${g}^{(2)}(0)=1$.

arXiv:1710.03031Physical Review AFeb 7, 20194 citations

Origin of Antibunching in Resonance Fluorescence

Lukas Hanschke, Lucas Schweickert, Juan Camilo López Carreño +14 more

Resonance fluorescence has played a major role in quantum optics with predictions and later experimental confirmation of nonclassical features of its emitted light such as antibunching or squeezing. In the Rayleigh regime where most of the light originates from the scattering of photons with subnatural linewidth, antibunching would appear to coexist with sharp spectral lines. Here, we demonstrate that this simultaneous observation of subnatural linewidth and antibunching is not possible with simple resonant excitation. Using an epitaxial quantum dot for the two-level system, we independently confirm the single-photon character and subnatural linewidth by demonstrating antibunching in a Hanbury Brown and Twiss type setup and using high-resolution spectroscopy, respectively. However, when filtering the coherently scattered photons with filter bandwidths on the order of the homogeneous linewidth of the excited state of the two-level system, the antibunching dip vanishes in the correlation measurement. Our observation is explained by antibunching originating from photon-interferences between the coherent scattering and a weak incoherent signal in a skewed squeezed state. This prefigures schemes to achieve simultaneous subnatural linewidth and antibunched emission.Resonance fluorescence has played a major role in quantum optics with predictions and later experimental confirmation of nonclassical features of its emitted light such as antibunching or squeezing. In the Rayleigh regime where most of the light originates from the scattering of photons with subnatural linewidth, antibunching would appear to coexist with sharp spectral lines. Here, we demonstrate that this simultaneous observation of subnatural linewidth and antibunching is not possible with simple resonant excitation. Using an epitaxial quantum dot for the two-level system, we independently confirm the single-photon character and subnatural linewidth by demonstrating antibunching in a Hanbury Brown and Twiss type setup and using high-resolution spectroscopy, respectively. However, when filtering the coherently scattered photons with filter bandwidths on the order of the homogeneous linewidth of the excited state of the two-level system, the antibunching dip vanishes in the correlation measurement. Our observation is explained by antibunching originating from photon-interferences between the coherent scattering and a weak incoherent signal in a skewed squeezed state. This prefigures schemes to achieve simultaneous subnatural linewidth and antibunched emission.

arXiv:2005.11800Physical Review LettersOct 23, 202060 citations

Excitation with quantum light. II. Exciting a two-level system

Juan Camilo López Carreño, Carlos Sánchez Muñoz, Elena del Valle +1 more

We study the excitation of a two-level system (2LS) by quantum light, thereby bringing our previous studies~(see part~I. of this series) to a target that is quantum itself. While there is no gain for the quantum state of the target as compared to driving it with classical light, its dynamical features, such as antibunching, can be improved. We propose a chain of two-level systems, i.e., setting the emission of each 2LS as the driving source of the following one, as an arrangement to provide better single-photon sources. At a fundamental level, we discuss the notion of strong-coupling between quantum light from a source and its target, and the several versions of the Mollow triplet that follow from various types of driving light. We discuss the Heitler effect of antibunched photons from the scattered light off a laser.We study the excitation of a two-level system (2LS) by quantum light, thereby bringing our previous studies~(see part~I. of this series) to a target that is quantum itself. While there is no gain for the quantum state of the target as compared to driving it with classical light, its dynamical features, such as antibunching, can be improved. We propose a chain of two-level systems, i.e., setting the emission of each 2LS as the driving source of the following one, as an arrangement to provide better single-photon sources. At a fundamental level, we discuss the notion of strong-coupling between quantum light from a source and its target, and the several versions of the Mollow triplet that follow from various types of driving light. We discuss the Heitler effect of antibunched photons from the scattered light off a laser.

arXiv:1609.00857Physical Review ADec 13, 201663 citations

Photon antibunching

Henryk Paul

A review is given of recent theoretical studies devoted to the problem of generating radiation fields that exhibit the opposite of the well-known bunching of photons observed in light from thermal sources, the so-called antibunching effect. It is made clear that this phenomenon reflects the corpuscular nature of light and, hence, cannot be interpreted in terms of classical electrodynamics, needing, instead, the quantum-mechanical formalism for its description. It is shown in some detail that nonlinear interaction mechanisms like multiphoton absorption and parametric three-wave interaction are suited to change the photon statistical properties of incident (in most cases coherent) light such that the output field will be endowed with antibunching properties. Special emphasis is given to the problem of correctly specifying the dimensions of the mode volume occurring in the usual single-mode treatment of the field, which is, in fact, of great practical interest, since the magnitude of the antibunching effect is determined by the inverse average number of photons contained in that volume. In a later section it is pointed out that destructive interference with a coherent reference beam provides a means of (a) effectively enhancing photon antibunching that is already present in a high-intensity field, through reduction of the intensity, and (b) transforming phase fluctuations produced in a Kerr medium into antibunching-type intensity fluctuations. On the other hand, there exists a way of directly generating light with antibunching properties, the physical mechanism being resonance fluorescence from a single atom. The main features of this technique, both theoretical and experimental, are outlined, including a discussion of the first experimental results obtained a few years ago.A review is given of recent theoretical studies devoted to the problem of generating radiation fields that exhibit the opposite of the well-known bunching of photons observed in light from thermal sources, the so-called antibunching effect. It is made clear that this phenomenon reflects the corpuscular nature of light and, hence, cannot be interpreted in terms of classical electrodynamics, needing, instead, the quantum-mechanical formalism for its description. It is shown in some detail that nonlinear interaction mechanisms like multiphoton absorption and parametric three-wave interaction are suited to change the photon statistical properties of incident (in most cases coherent) light such that the output field will be endowed with antibunching properties. Special emphasis is given to the problem of correctly specifying the dimensions of the mode volume occurring in the usual single-mode treatment of the field, which is, in fact, of great practical interest, since the magnitude of the antibunching effect is determined by the inverse average number of photons contained in that volume. In a later section it is pointed out that destructive interference with a coherent reference beam provides a means of (a) effectively enhancing photon antibunching that is already present in a high-intensity field, through reduction of the intensity, and (b) transforming phase fluctuations produced in a Kerr medium into antibunching-type intensity fluctuations. On the other hand, there exists a way of directly generating light with antibunching properties, the physical mechanism being resonance fluorescence from a single atom. The main features of this technique, both theoretical and experimental, are outlined, including a discussion of the first experimental results obtained a few years ago.

Reviews of Modern PhysicsOct 1, 1982328 citations

Two-photon spectra of quantum emitters

Alejandro González-Tudela, Materia Condensada, Fabrice P. Laussy +3 more

Abstract. We apply our recently developed theory of frequency-filtered and time-resolved N-photon correlations [1] to study the two-photon spectra of a variety of systems of increasing complexity: single mode emitters with two limiting statistics (one harmonic oscillator or a two-level system) and the various combinations that arise from their coupling. We consider both the linear and nonlinear regimes under incoherent excitation. We find that even the simplest systems display a rich dynamics of emission, not accessible by simple single photon spectroscopy. In the strong coupling regime, novel two-photon emission processes involving virtual states are revealed. Furthermore, two general results are unraveled by two-photon correlations with narrow linewidth detectors: i) filtering induced bunching and ii) breakdown of the semi-classical theory. We show how to overcome this shortcoming in a fully-quantized picture. PACS numbers: 42.50.Ar,42.50.Lc,05.10.Gg,42.25.Kb,42.79.Pw ar X ivAbstract. We apply our recently developed theory of frequency-filtered and time-resolved N-photon correlations [1] to study the two-photon spectra of a variety of systems of increasing complexity: single mode emitters with two limiting statistics (one harmonic oscillator or a two-level system) and the various combinations that arise from their coupling. We consider both the linear and nonlinear regimes under incoherent excitation. We find that even the simplest systems display a rich dynamics of emission, not accessible by simple single photon spectroscopy. In the strong coupling regime, novel two-photon emission processes involving virtual states are revealed. Furthermore, two general results are unraveled by two-photon correlations with narrow linewidth detectors: i) filtering induced bunching and ii) breakdown of the semi-classical theory. We show how to overcome this shortcoming in a fully-quantized picture. PACS numbers: 42.50.Ar,42.50.Lc,05.10.Gg,42.25.Kb,42.79.Pw ar X iv

Jan 1, 201396 citations

{g}^{(2)}(0)=1