Nonlinear quantum optics

One of the many critical insights of quantum field theory in the 20th century was the realization that the electromagnetic field is inherently quantum mechanical in nature. This understanding, along with the birth of the laser, have led to the development of the mature field of “quantum optics,” which is concerned with the measurement and manipulation of quantum states of light. My involvement with quantum nonlinear optics can be divided into two key areas.

Quantum optics of nonlinear dissipation

We recently proposed a new family of systems which exhibit strong engineered nonlinear dissipation to gain control over the classical and quantum properties of radiation. In particular, we showed that nonlinear dissipation can be engineered in a way which lends itself to the natural generation of Fock states of light, as well as approximations of Fock states with intensity noise far below the shot noise limit.

References:

1. N Rivera, J Sloan*, Y Salamin, JD Joannopoulos, M Soljačić. "Creating large Fock states and massively squeezed states in optics using systems with nonlinear bound states in the continuum." *PNAS (2023).

2. L Nguyen, J Sloan, N Rivera, M Soljačić. "Intense squeezed light from lasers with sharply nonlinear gain at optical frequencies." arXiv:2306.01908 (2023).

3. S Pontula, J Sloan*, N Rivera, M Soljačić. "Strong intensity noise condensation using nonlinear dispersive loss in semiconductor lasers." arXiv:2212.07300 (2022).

Quantum optics as a resource for controlled randomness

One of the key features of quantum optics is that even in the seeming absence of light, so-called “vacuum fluctuations” of the electromagnetic field are always present due to the Hesisenberg uncertainty principle. This fact underlies many famous phenomena such as the spontaneous emission of atoms, the Lamb shift, Casimir and Casimir-Polder forces, and more. Another more recent application of these quantum vacuum fluctuations is in the generation of random bits or numbers, which may see future applications in photonic probabilistic computing. We recently used a carefully designed optical parametric oscillator (OPO) system to show that biased vacuum fluctuations can be used to create a tunable random bit generator.

References:

1. C Roques-Carmes, Y Salamin, J Sloan, S Choi, G Velez, E Koskas, N Rivera, S E Kooi, J D Joannopoulos, M Soljačić. "Biasing the quantum vacuum to control macroscopic probability distributions." Science (2023).