Photon-photon correlations from a pair of strongly coupled two-level emitters

Abstract

We investigate two-color photon correlations in the light emitted by strongly coupled two-level emitters. Spectral filtering allows us to manipulate the collected light statistics and we show that the resonances induced by dipole-dipole interactions give rise to specific correlations, where the timesymmetry of the correlations is broken. Based on the collective dressed states, our study encompasses both the case of real processes, where the photons are associated with specific resonances and classical correlations between each other, and virtual processes, where pairs of photons are emitted with non-classical correlations.

Two-photon resonance fluorescence of two interacting non-identical quantum emitters

“…(44)(45)(46)(47)(48)(49), however, are not visible for all values of β. The case of coupled identical emitters β = 0 features only three positive sidebands, yielding a total of seven peaks as has been noted before [8,18]. In particular, the peaks that are not visible are those that involve transitions that start or end at the one-photon antisymmetric state |A , which for the perturbative regime correspond to the peaks ω 2 , ω 5 and ω 6 in Eqs.…”

“…The resonance fluorescence spectrum of two interacting quantum emitters displays a more complex structure than the Mollow triplet, which has been reported for the case of identical emitters [8,18], and for the analogous case of a coherently driven three-level system at the two-photon resonance [72]. The resulting spectrum has a seven-peaked structure with a central peak and six sidebands.…”

“…superradiant emission and dark states [2,5]. Minimal models of two and three quantum emitters have been studied extensively in the literature [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20], and examples of emergent phenomenology include superradiance [21,22], generation of qubit entanglement [12,23,24] and spin and light squeezing [25][26][27], non-classical photon correlations [11,[17][18][19], emission of entangled photons [20], and potential for molecule localization with nanometer resolution [28,29]. The insights provided by these minimal theoretical models apply to a large variety of physical systems, including coupled quantum dots [30][31][32][33], trapped ions [21,34], Rydberg atoms [35][36][37], molecular systems [28,29], and superconducting qubits [22,…”

The resonance fluorescence cascade of a laser-excited two-level atom

“…We now discuss the photon-correlation signal that has been studied theoretically [17][18][19][20] and experimentally [12,13]. This correlation reveals the antibunching effect that has been used as a characterization tool for a large variety of systems of physical interest [41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56][57][58].…”

Resonance fluorescence of two asymmetrically pumped and coupled two-level systems

“…Resonance fluorescence in two-atom [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37] and indeed many-atom [38][39][40][41] systems was inevitably studied theoretically soon afterwards in order to elucidate the influence of cooperative effects, including the emergence of additional sidebands in the optical spectrum. More recently, modern experiments with two artificial atoms in superconducting circuits have offered the control and tunability required to study the properties of quantum dimers under coherent excitation [42].…”