Observation and characterization of cavity Rydberg polaritons

Abstract

We demonstrate hybridization of optical cavity photons with atomic Rydberg excitations using electromagnetically induced transparency (EIT). The resulting dark state Rydberg polaritons exhibit a compressed frequency spectrum and enhanced lifetime indicating strong light-matter mixing. We study the coherence properties of cavity Rydberg polaritons and identify the generalized EIT linewidth for optical cavities. Strong collective coupling suppresses polariton losses due to inhomogeneous broadening, which we demonstrate by using different Rydberg levels with a range of polarizabilities. Our results point the way towards using cavity Rydberg polaritons as a platform for creating photonic quantum materials.PACS numbers: 42.50. Gy, 42.50.Pq, 32.80.Ee, 71.36.+c Coupling photons to electronic excitations of a medium leads to hybrid quasiparticles, or polaritons, that carry properties of both light and matter. The photonic component allows polaritons to propagate like light, while the material component enables interactions between polaritons. An important example is exciton polaritons in semiconductor microcavities, which exhibit an effective mass and two-dimensional motion arising from the photonic component, while the exciton component leads to a mean-field interaction, allowing Bose-Einstein condensation [1][2][3]. Rydberg polaritons in atomic gases enable strong interactions even at the few-quantum level [4][5][6][7][8][9][10][11][12], a key ingredient for producing highly correlated states, including fractional quantum Hall states [13][14][15][16][17] and emergent quantum crystals [17][18][19][20][21]. While previous work on Rydberg polaritons has focused on onedimensional free-space light fields, photons in optical cavities provide access to two-dimensional motion, harmonic trapping [22], and effective magnetic fields [17,23]. In addition, optical cavities can enhance the optical nonlinearity arising from Rydberg interactions [24,25].Rydberg polaritons are formed by coherently coupling light to a highly excited atomic Rydberg level using electromagnetically induced transparency (EIT) [26]. At EIT resonance, destructive interference prevents population of a lossy intermediate atomic level, resulting in a dark state polariton [27] that consists of a superposition of a photon and a collective atomic Rydberg excitation. A large admixture of the (long-lived) atomic excitation in a dark state polariton slows all photonic dynamics [27]. In an optical cavity, this results in a polariton whose lifetime can exceed the empty-cavity lifetime by orders of magnitude, and an energy that is pulled toward the EIT resonance [28][29][30][31][32][33]. In a multimode cavity, hybridization rescales the trap frequency and effective mass of the polariton [17].We experimentally observe Rydberg polaritons in an optical cavity and explore the spectral and coherence properties of these collective states in cavity transmission spectroscopy. While Doppler decoherence and inhomogeneous Stark shifts [35][36][37] are more significant for Rydbe...

Generation and spectroscopic signatures of a fractional quantum Hall liquid of photons in an incoherently pumped optical cavity

“…In contrast to the lattice geometries of [5], the multimode dynamics takes place in this system along the continuous two-dimensional transverse plane and has already revealed photonic Landau levels in the synthetic magnetic field. Strong photon-photon effective interactions can then be induced by coupling photons to atomic transitions in the so-called Rydberg EIT configuration [8]: the strong interactions between Rydberg atoms translate in analogous interactions between polaritons [9] and first experimental evidence of photon blockade in the lowest mode has been recently reported in [10].…”

Measurement of many-body chaos using a quantum clock

“…While such models can be realized in most of quantum simulation platforms, ranging from cavity quantum electrodynamics (QED) [15][16][17][18] to Rydberg atoms [29][30][31][32], and trapped ions [33] systems, motivated by recent advances in superconducting circuits, we focus our discussion on circuit-QED architecture.…”

“…From an experimental standpoint, our protocol is motivated by the rapid development of quantum simulation and information technology in recent years, such as cavity quantum electrodynamics (QED) [15][16][17][18], circuit-QED [19][20][21][22][23][24][25][26][27][28], Rydberg atoms [29][30][31][32], and trapped ions [33]; it is within current technology to engineer an ancilla qubit coupled to a manybody system globally. The ancilla qubit can be either the cavity photon mode or the internal state of an atom.…”

Active cancellation of acoustical resonances with an FPGA FIR filter

“…We place before the ADC input of the FPGA an anti-aliasing low-pass filter whose corner frequency, ω corner = 2π × 100 kHz, has been chosen to trade-off between suppressing aliased noise and the phase lag induced by the anti-aliasing filter itself. We apply the FIR filter to canceling the acoustical resonances present in a high-finesse optical resonator designed for Rydberg cQED experiments [22]. In order to have a small waist size of about 10 µm, comparable to Rydberg blockade, the resonator consists of four mirrors in a bow-tie configuration, one of which is mounted on a single-layer piezoelectric tube actuator.…”