Anti-Hong-Ou-Mandel effect with coherent perfect absorbers

Abstract

Coherent interaction of light beams in the presence of a thin absorber allows to operate between the regimes of total light absorption and total light transmission. It was demonstrated that such absorbers (coherent perfect absorber, CPAs) provide nonlinear input-output signal dependencies and enables light-by-light control without requiring intrinsic nonlinearity. All-optical logical gates, signal amplification and dark pulse generation were demonstrated with CPAs and classical (laser) light. Beyond this, recent experimental studies showed that CPAs enable manipulation of quantum states of light including single photon and NOON states. Here, we extend quantum regimes of CPAs by interfering bosonic and fermionic states of entangled photons. In a single experiment we compare interference of bosonic and fermionic states in the absence and presence of dissipation. Lossless interference results in the Hong-Ou-Mandel effect where bosons coalesce and fermions anti-coalesce. In contrast, lossy interference with CPAs has the opposite outcome with anti-coalescent bosons and ‘coalescent’ fermions. We provide analysis of this ‘reversed’– anti-Hong-Ou-Mandel effect, and show that it originates from the phenomena of probabilistic two-photon absorption for bosonic pairs and deterministic one-photon absorption for fermionic pairs. The ability to manipulate and control the behaviour of photons and their output statistics with CPAs offers novel approaches for quantum information and metrology applications.