Beam splitting and Hong-Ou-Mandel interference for stored light

Storing and release of a quantum light pulse in a medium of atoms in the tripod configuration are studied. Each of these operations is realized by switching on and off two sets of properly chosen control fields. The system constitutes a kind of a flexible beam splitter in which the input and output ports concern photons of the same direction but well separated in time. A version of Hong-Ou-Mandel interference is discussed. It is also shown that a stored nonclassical light is split into two nonclassical beams, with their statistical properties being steered by a choice of the control fields.

Figure 1

Level and coupling scheme of the tripod system.

Figure 2

The probability of photon noncoalescence as a function of the packet’s separation $a$ for ${\delta }_1={\delta }_2$ solid line and ${\delta }_1=3{\delta }_2$, dashed line.

Figure 3

The probability of photon noncoalescence as a function of the ratio ${\delta }_2∕{\delta }_1$ of the packets’ widths for $a=0$, solid line, and $a=2{\delta }_1$, dashed line.

Figure 4

(Color online) The index $W\left(N_3\right)∕⟨N_3⟩$ of sub-Poissonian character of the released light as a function of the mixing angle ${\varphi }^1$ and the phase ${\chi }_2^1$ for $W\left(N_1\right)∕⟨N_1⟩=\frac{1}{2}$, ${\varphi }_0=\frac{\pi }{4}$, and ${\chi }_2^0={\chi }_3^0={\chi }_3^1=0$.