While for the most part quantum statistical processes in quantum optics are investigated in a weak-coupling regime, it has recently become possible to realize experimentally systems for which the internal coupling coefficient g is comparable to the external dissipative rates. Within this context the subject of our investigation is the quantum dynamical processes for a collection of N two-state atoms strongly coupled to a single mode of a high finesse optical cavity. Our particular system consists of a collection of N~20 Cesium atoms (6S 1/2, f = 4– > 6P 3/2, f = 5 transition at 852 nm) interacting with the TEMoo mode of a spherical mirror cavity of finesse 4 × 104. Of principal importance are the single atom cooperativity parameter C1 = g 2/κγ and the saturation photon number no = g2/8γ 2, where (κ,γ) are the cavity and atomic decay rates. For our system, c1~1 and n0~0.5. In measurements of the joint probability of photoelectric detection we observe photon antibunching and sub-Poissonian photon statistics.1,2 An interpretation of our results in terms of quantum state reduction and interference in a dissipative dynamical setting is presented.2 We emphasize the decisive role played by the quantum fluctuations of a single atom (c1~1), which can result in a field of large variance even in the presence of N>1 atoms.
While for the most part quantum statistical processes in quantum optics are investigated in a weak-coupling regime, it has recently become possible to realize experimentally systems for which the internal coupling coefficient g is comparable to the external dissipative rates. Within this context the subject of our investigation is the quantum dynamical processes for a collection of N two-state atoms strongly coupled to a single mode of a high finesse optical cavity. Our particular system consists of a collection of N20 Cesium atoms (6S 1/2, f = 4– > 6P 3/2, f = 5 transition at 852 nm) interacting with the TEMoo mode of a spherical mirror cavity of finesse 4 × 104. Of principal importance are the single atom cooperativity parameter C1 = g 2/κγ and the saturation photon number no = g2/8γ 2, where (κ,γ) are the cavity and atomic decay rates. For our system, c11 and n00.5. In measurements of the joint probability of photoelectric detection we observe photon antibunching and sub-Poissonian photon statistics.1,2 An interpretation of our results in terms of quantum state reduction and interference in a dissipative dynamical setting is presented.2 We emphasize the decisive role played by the quantum fluctuations of a single atom (c11), which can result in a field of large variance even in the presence of N>1 atoms.
While for the most part quantum statistical processes in quantum optics are investigated in a weak coupling regime, it has recently become possible to realize experimentally optical systems for which the internal coupling coefficient g is comparable to the external dissipative rates. Within this context the subject of our investigation is the quantum dynamical processes for a collection of N two-state atoms strongly coupled to a single mode of a high finesse optical cavity, Our particular experiment consists of a small collection of Cesium atoms (6S1/2, F = 4 → 6P3/2, F = 5 transition at 852nm) interacting with the TEM00 mode of a spherical mirror cavity. The critical technical advance for this work is the attainment of extremely low loss mirrors for high finesse (103 – 106) and hence long photon lifetime even in a small cavity.[1]
For the most part, quantum statistical processes in quantum optics are investigated in a weak-coupling regime, but it has become possible recently to realize experimentally optical systems for which the internal coupling coefficient g is comparable to the external dissipative rates. Within, this context, the subject of our investigation is the quantum dynamical processes for a small collection of N two-state atoms strongly coupled to a single mode of a high-finesse optical cavity. For this system, we record input-output characteristics for steady-state operation with 3 ⪝ N ⪝ 65 intracavity atoms and observe optical bistability for N⪞15 atoms.1
We present analytic results for the photon statistics of a weakly driven optical cavity containing N two-level atoms. The second-order intensity correlation function g(2)() is calculated in the weak field limit for arbitrary atomic and cavity loss rates, and cavity and atomic detunings are included. The transmitted light field may exhibit photon antibunching, sub-Poissonian photon statistics, and other novel nonclassical effects.1,2 The size of these effects depends principally on the single-atom coupling constant C1 = g2/κγ, so these effects persist with many atoms in the cavity. Our results can be interpreted via the collapse of the wave function and quantum interference of probability amplitudes. These phenomena can also be understood in terms of the self-homodyning of the driving field with squeezed polarization fluctuations.2
Of fundamental importance in quantum optics has been the investigation of the radiative coupling of a collection of atoms to the field of a resonant cavity1. Within this context we are conducting a research program to investigate the interaction of optically prepared two-state atoms with the fields of high finesse optical cavities. With regard to our specific observations, we have employed a sodium atomic beam apparatus to make direct spectroscopic measurements of the normal-mode splitting for the coupled oscillator system formed by the collective atomic polarization of N two-state atoms and a single mode of a resonator of finesse of approximately 2x10⁴. At the transition wavelength of 589 nm (³, S_(1/2), F = 2, m_F = 2→3 P_(3/2), m_F = 3 and for one of our spherical mirror standing-wave cavities, the relevant parameters for the system are as follows: transverse atomic decay rate γ_⊥ = 2πX5X10⁶/S, cavity damping rate K/γ⊥= 0.18, and single-atom coupling coefficient g/γ_⊥ = 0.2.
Investigations of the radiative processes for the composite system of N two-state atoms coupled to the field of a high finesse optical cavity are reported. In an experiment employing an atomic beam of optically prepared sodium atoms (3S1/2, F = 2, mF = 2 → 3P3/2, F = 3, mF = 3 transition at 589 nm), we make direct spectroscopic measurements of the normal mode splitting for the coupled oscillator system of atoms and cavity field over a 20 ≤ N ≤ 600 range. Linewidth reduction below the atomic free-space width is observed and results from dynamic linewidth averaging due to the strong coherent interaction of atoms and cavity. The dependence of the normalmode structure on atom-cavity detuning is explored, and the decoupling of the system with detuning is described. A second experimental program employs a cesium atomic beam (6S1/2, F = 4, mF = 4 → 6P3/2, F = 5, mF = 5 transition at 852 nm), for which the single-atom coupling coefficient can be made larger than the free-space atomic and cavity damping rates. Our initial efforts are directed both toward the investigation of the spectroscopic properties of this system and toward the observation of photon antibunching for the field transmitted from the cavity. More generally our measurements of intensity correlations can be applied to the problem of continuous quantum measurement for a dissipative system.
We consider an optical cavity containing a single two-level atom driven on resonance by an external laser source.1 We focus on the limit of weak excitation where the dynamic response of this system is governed by just three parameters: the atom-field coupling constant g, spontaneous emission rate γ for the atom, and cavity decay rate κ. The statistics of the transmitted light are analyzed as a function of g, γ, and κ, in terms of the second-order correlation function g(2)(τ), and the quadrature variances measured in a homodyne detection scheme. Squeezing and photon antibunching exist over a wide range of parameters. For γ ~ κ, the system can exhibit an oscillatory response, even when the mean intracavity photon number is much less than unity.2 The oscillations can be understood in terms of the coupling between the free atom-field eigenstates |0,−>, |0,+>, and |1,−>. The oscillation frequency is determined by the energy level splitting produced between the degenerate one-quantum states |0,+> and |1,−> by the atom-field interaction. The second-order correlation function can exhibit a novel nonclassical effect, where, for g(2)(0) ≠ 0, at some finite delay τ0, the correlation function dips exactly to zero—g(2)(τ0) = 0.