Rostock 2019 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 8: Quantum Optics and Photonics I

Q 8.6: Talk

Monday, March 11, 2019, 11:45–12:00, S Ex 04 E-Tech

Theoretical description of a multi-mode SU(1,1) interferometer using matrix approach — •Alessandro Ferreri, Polina Sharapova, Kai Hong Lou, Harald Herrmann, and Christine Silberhorn — University of Paderborn, Paderborn, Germany

Photon sensing is an important branch of Quantum Metrology and one of the main task thereof is to improve the precision of the measurement via overcoming the classical shot noise limit (SNL) and reaching the quantum limit, called Heisenberg limit (HL).

In this work we show the protocol we used in order to investigate a new type of device, called SU(1,1) interferometer, which is able to overcome the SNL even by using vacuum input state. We considered a SU(1,1) interferometer having two multi-mode parametric down-conversion (PDC) sections. By performing the Schmidt decomposition of joint spectral amplitude (JSA), we are able to describe the PDC processes in terms of multi-mode squeezers and we can therefore use a matrix approach to investigate features of such interferometer. This technique allows to explore the SU(1,1) with two identical or different JSAs of the crystals. The influence of the gain as well as the number of modes on properties of the SU (1,1) interferometer is taken into account. It was shown that in the case of two identical JSAs a perfect interference between the signal and idler photons occurs and a supersensitivity region appears, whereas the interference process is partially inhibited for two different JSAs .