Proposal for a Deterministic Single-Atom Source of Quasisuperradiant $N$-Photon Pulses

We propose a single-atom, cavity quantum electrodynamics system, compatible with recently demonstrated, fiber-integrated micro- and nanocavity setups, for the on-demand production of optical number-state, $0N$-state, and binomial-code-state pulses. The scheme makes use of Raman transitions within an entire atomic ground-state hyperfine level and operates with laser and cavity fields detuned from the atomic transition by much more than the excited-state hyperfine splitting. This enables reduction of the dynamics to that of a simple, cavity-damped Tavis-Cummings model with the collective spin determined by the total angular momentum of the ground hyperfine level.

Figure 1

Fiber-cavity configuration with a ${\sigma }_{+}$-polarized laser and $\pi$-polarized cavity mode coupled to the $D_1$ line of a ${}^{87}\mathrm{Rb}$ atom. The atom is initially prepared in the $\{F=2,m_F=-2\}$ ground-state sublevel. The cavity field decays predominantly through the right-hand mirror.

Figure 2

Top row: Output photon flux for a ${}^{87}\mathrm{Rb}$ atom initially prepared in $|F=2,m_F=-2⟩$. The black solid line represents the full model and the red dashed line the anti-TCM. The histogram shows the temporal distribution of photocounts (renormalized to $\overline{N}$) for 10 000 trajectories of the anti-TCM with additional, effective spontaneous emission. The number below the curves gives $\overline{N}$ for the full model. Insets: Histogram of photon number counts per trajectory (i.e., per output pulse). Bottom row: Atomic ground state populations ($F=2$: main plot, $F=1$: inset), and total excited state population (inset, red-dashed) as a function of time.

Figure 3

Output photon flux for a ${}^{133}\mathrm{Cs}$ atom initially prepared in $|F=4,m_F=-4⟩$. Line markings, histograms, and annotations are the same as described in Fig. 2.

Figure 4

Output photon flux for a ${}^{87}\mathrm{Rb}$ atom initially prepared in the states $|{\psi }_{\mathrm{oat}}{⟩}_{F=2}$ (left) and $|{\psi }_{\mathrm{bc}}{⟩}_{F=2}$ (right). Line markings, histograms, and annotations are the same as described in Fig. 2. Note the larger detuning used here, which leads to a slower timescale than in Fig. 2.

Figure 5

Top row: Wigner functions of the states (left to right) $|4⟩$, $(|0⟩+|4⟩)/\sqrt{2}$, and $(|0⟩+\sqrt{2}|2⟩+|4⟩)/2$. Bottom row: raw reconstructed Wigner functions of the cavity output pulses for a single ${}^{87}\mathrm{Rb}$ atom in a fiber microcavity setup ($\{\kappa ,g,\mathrm{\Delta },\mathrm{\Omega }\}=\{0.05,0.25,-50,2\}·2\pi \mathrm{GHz}$) with initial atomic states (left to right) $|2,-2⟩$, $|{\psi }_{\mathrm{oat}}{⟩}_{F=2}$, and $|{\psi }_{\mathrm{bc}}{⟩}_{F=2}$. The reconstructions are using a set of 500 angles $\theta \in [0,\pi )$ and 10 000 trajectories per angle. Middle row: Simulated reconstructions smoothed by a Gaussian blur.