Optical Synthesis of Large-Amplitude Squeezed Coherent-State Superpositions with Minimal Resources
Kun Huang, Hanna Le Jeannic, Josselin Ruaudel, Varun Verma, Matthew D. Shaw, Francesco Marsili, Sung‐Wook Nam, E Wu, Hao‐Sheng Zeng, Youngmin Jeong, Radim Filip, Olivier Morin, Julien Laurat · Physical Review Letters · 2015
We propose and experimentally realize a novel versatile protocol that allows the quantum state engineering of heralded optical coherent-state superpositions. This scheme relies on a two-mode squeezed state, linear mixing, and a n-photon detection. It is optimally using expensive non-Gaussian resources to build up only the key non-Gaussian part of the targeted state. In the experimental case of a two-photon detection based on high-efficiency superconducting nanowire single-photon detectors, the freely propagating state exhibits a 67% fidelity with a squeezed even coherent-state superposition with a size |α|(2)=3. The demonstrated procedure and the achieved rate will facilitate the use of such superpositions in subsequent protocols, including fundamental tests and optical hybrid quantum information implementations.