Strong-Field Spatial Interference in a Tailored Electromagnetic Bath

Light scattered by a regular structure of atoms can exhibit interference signatures, similar to the classical double-slit. These first-order interferences, however, vanish for strong light intensities, restricting potential applications. Here, we show how to overcome these limitations to quantum interference in strong fields. First, we recover the first-order interference in strong fields via a tailored electromagnetic bath with a suitable frequency dependence. At strong driving, the optical properties for different spectral bands are distinct, thus extending the set of observables. We further show that for a two-photon detector as, e.g., in lithography, increasing the field intensity leads to twice the spatial resolution of the second-order interference pattern compared to the weak-field case.

Figure 1

Two nearby two-state emitters $a$ and $b$, separated by ${\overrightarrow{r}}_{ab}$, and driven by a resonant strong external laser field with wave vector ${\overrightarrow{k}}_L$. Detectors $\{D_1,D_2\}$ are used to measure correlations among the emitted photons. $\{{\alpha }_1,{\alpha }_2\}$ are the angles between ${\overrightarrow{r}}_{ab}$ and the observation directions $\{{\overrightarrow{R}}_1,{\overrightarrow{R}}_2\}$.

Figure 2

Central-band visibility $V_{\mathrm{CB}}$ as a function of $\eta$ for $\theta =\pi /4$ and $k_L{r}_{ab}\gg 2\pi$.

Figure 3

Central-band intensity $I_{\mathrm{CB}}({\overrightarrow{R}}_1)/N^2$ [in units of ${\Psi }_{R_1}({\omega }_L)/4$] as a function of ${\alpha }_1$. Here $\theta =\pi /4$, $k_L{r}_{ab}=20\pi$ and $V_{\mathrm{CB}}=0.9$. Solid line: $N=8$, dashed curve: $N=2$.

Figure 4

Central-band second-order correlation function $g_{\mathrm{CB}}^{(2)}({\overrightarrow{R}}_1,{\overrightarrow{R}}_2)$. The solid line depicts the strong-field limit ($V_{\mathrm{CB}}=0$) while the dashed curve describes the weak-field case with $\Omega /\gamma =0.9$. Here $\Delta =0$, $k_L{r}_{ab}=20\pi$, and ${\overrightarrow{R}}_1={\overrightarrow{R}}_2$.