SAMOP 2023 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 42: Poster III

Q 42.3: Poster

Wednesday, March 8, 2023, 16:30–19:00, Empore Lichthof

Orbital angular momentum modes generated in the parametric down-conversion process with a non-Gaussian pump — •Lucas Gehse, Dennis Scharwald, and Polina Sharapova — Universität Paderborn, Paderborn, Germany

Electric fields can carry two types of angular momentum. The first is the spin angular momentum, which arises from the polarization of the light, and the second is the orbital angular momentum (OAM) which arises from the light phase distribution. OAM modes have an unlimited basis, which makes them very promising for fast and efficient quantum information and communication protocols [1]. It has recently been shown that a radially symmetric parametric down-conversion (PDC) process is a good source of photons with perfectly anti-correlated orbital numbers in both low- and high-gain regimes [2]. In this work, we investigate an SU(1,1) interferometer consisting of two PDC sources, which are two nonlinear crystals pumped by a Laguerre−Gaussian pump with different orbital and radial numbers. We consider various crystal lengths, pump widths and distances between the crystals, in order to find configurations with high-order OAM modes populated. We have found configurations in which up to 120 OAM modes can be generated using a pump with different orbital numbers. Mode shapes and intensity profiles for various configurations of the SU(1,1) interferometer in the low- and high-gain regimes were investigated and discussed.
[1] Manuel Erhard et al., Light Sci Appl 7, 17146 (2018)
[2] Lina Beltran et al., J. Opt. 19, 044005 (2017)