CPM Seminar

Introducing the Ramaniton: The quasiparticle for Raman scattering

Rogério de Sousa

Department of Physics and Astronomy
University of Victoria

In Raman scattering, pump photons that are incident on a material are able to emit or absorb materials' excitations such as phonons and orbital transitions. This process generates red-shifted (Stokes) and blue-shifted (antiStokes) photons that are usually uncorrelated with each other. When real or virtual excitations emitted by a Stokes photon are coherently absorbed by another pump photon, an entangled Stokes-antiStokes photon pair is created, in a process analogous to the formation of Cooper pairs in superconductors [1].

In this talk we will show that this mechanism provides the microscopic underpinning for the phenomena of four-wave mixing in quantum optics, one of the main methods to generate squeezed states of light that are key to proposals of quantum computing, sensing, and communication with photons.

We will argue that it's fruitful to take a “condensed matter physics approach” and treat Raman-interacting photons and phonons as a hybrid excitation, the Ramaniton quasiparticle [2].

The Ramaniton enables nonperturbative theories for the evolution of photons in waveguides formed by group IV semiconductors such as silicon and diamond, enabling the design of photonic devices that exploit optical phonons for optimal generation of two-mode squeezed states of light.

[1] A. Saraiva, F.S.D.A. Júnior, R. De Melo E Souza, A.P. Pena, C.H. Monken, M.F. Santos, B. Koiller, and A. Jorio, Photonic Counterparts of Cooper Pairs, Phys. Rev. Lett. 119, 193603 (2017).
[2] S. Timsina, T. Hammadia, S.G. Milani, F.S.D.A. Júnior, A. Brolo, and R. de Sousa, Resonant squeezed light from photonic Cooper pairs, Phys. Rev. Res. 6, 033067 (2024).