Signatures of single-site addressability in resonance fluorescence spectra

Abstract

Pioneering methods in recent optical lattice experiments allow to focus laser beams down to a spot size that is comparable to the lattice constant. Inspired by this achievement, we examine the resonance fluorescence spectra of two-level atoms positioned in adjacent lattice sites and compare the case where the laser hits only one atom (single site addressing) with cases where several atoms are illuminated. In contrast to the case where the laser hits several atoms, the spectrum for single site addressing is no longer symmetric around the laser frequency. The shape of the spectrum of fluorescent light can therefore serve as a test for single site addressing. The effects we find can be attributed to a dipole-dipole interaction between the atoms due to mutual exchange of photons.

Two-photon spectra of quantum emitters

“…Such correlations can be further taken advantage of by considering finite time delays and/or optimizing the frequency windows. Further interesting systems to apply two-photon spectroscopy are ultra-strong coupling systems [65], closely spaced atoms in an optical lattice [66], the biexciton two-photon emission in a quantum dot [42,64] or the dynamics of Bose-Einstein condensation [67].…”

Degenerate optomechanical parametric oscillators: Cooling in the vicinity of a critical point

“…To get simple analytic expressions that enable physical insight, we first apply standard linearization to the optical problem, which we denote by semi-classical approach and has been the method of choice in previous works [19][20][21][22]. Next, applying c-MoP theory [25] we show the failure of the semi-classical approach close to the critical point and find more accurate expressions at criticality, which will also allow us to justify the adiabatic elimination of the optical modes.…”

“…It is however well known that this approximation fails close to the critical point, although there is no systematic way of checking where exactly within the semi-classical formalism itself. Hence, to determine where it exactly breaks down and to find more accurate results for those parameters, we make use of the recently developed c-MoP technique [24,25], which allows finding reduced equations for the constituent parts of a composite system, even in situations where there is significant backaction among its parts and no time-scale separation between their dynam-Photon numberN s 0.99900.99920.99940.99960.99981.0000 (Color online) Termsn th /Γ andnFL contributing to the steady-state phonon number (4) as a function of the distance-to-threshold parameter x. We fix the detuning to ∆ = 75, corresponding to the straight thin solid line in Fig.…”

“…For parameters compatible with cWGM resonators, the theory is already regularized by using c-MoP only in the optical problem (DOPO), which provides a more accurate description for the optical correlation function (5) and photon number that enter the effective mechanical dynamics. The application of c-MoP to the DOPO has been detailed in [25], but we review its most relevant steps for completeness in Appendix D. Specifically, we use a combination of c-MoP and a Gaussian-state approximation, which provides an efficient and accurate tool capable of regularizing the divergencies and unphysical predictions of the semi-classical approach. In particular, we show in Appendix D that at threshold the decay rate of the optical correlator scales as γ opt ∝ γ 0 η DC (1 + ∆), while the photon number asN s ∝ (1 + ∆)/η DC , in contrast to semi-classical results in which the former goes to zero while the latter diverges.…”

“…In contrast, the description of the interaction between the field generated via spontaneous down-conversion and the mechanical mode is much * peter.degenfeld-schonburg@ph.tum.de † carlos.navarrete@mpq.mpg.de more challenging, since (below threshold) the former is purely quantum mechanical [23], so that the optomechanical coupling cannot be linearized and does not admit a simple Gaussian description. In this work we provide a theory for the DOMPO which can be trusted all the way to threshold, and is obtained by combining traditional adiabatic elimination techniques with our recently developed self-consistent Mori projector (c-MoP) theory [24,25]. To this end we first introduce the master equation which models the DOMPO, and perform an adiabatic elimination of the optical modes by neglecting the mechanical backaction.…”