Controlling the spatiotemporal quantum noise of light

Noise presents a fundamental limit to the precision of sensitive measurements made using light.  Interactions between photons mediated by nonlinear optical materials allow generating a range of states such as squeezed states and entangled states with nonclassical noise properties, which can extend the sensitivity of a range of instruments such as interferometers, microscopes, and imaging systems. While the prospects for generating such quantum light states should improve as we increase light intensity and enhance interactions between photons, a challenge is that high-intensity light beams tend to have fluctuations far in excess of the value expected if these light beams were in quantum mechanical coherent-states – making it challenging to produce light with nonclassical noise properties.

Here, we present several techniques that we have developed in order to produce light with quantum statistics from intense beams with large excess noise. In one technique we the quantum correlations that are generated between frequency components of a femtosecond pulse in a nonlinear medium. These correlations make it possible to filter out a portion of the pulse that is maximally decoupled from the dominant noise in the pulse before it enters the nonlinear medium. We use this to demonstrate the creation of light with intensity fluctuations at or below the shot noise level, even when the input pulses have large excess noise. We then show that in spatiotemporally multimode nonlinear systems, it is possible to perform a similar decoupling via an optimized spatial phase modulation of the input beam. The ideas explored here are also applicable in the regime where a few photons are needed to realize nonlinearities, presenting prospects for generating non-Gaussian quantum optical states such as Fock and Schrodinger cat states in a deterministic way.
 

Bio: Nicholas Rivera earned his Ph.D in physics from the Massachusetts Institute of Technology, where he worked on enhancing light-emission using nanophotonic structures, developing proposals to enable new emission pathways using nanophotonic systems such as plasmons and polaritons. He also developed a technique to enhance scintillators using nanophotonic structures such as photonic crystals. He then moved to Harvard University for his postdoc, where he worked on techniques to understand and control quantum noise dynamics in multimode nonlinear optical systems in systems with bulk and few-photon nonlinearities. His research has been recognized with awards such as the LeRoy Apker Award of the American Physical Society, a Junior Fellowship from the Harvard Society of Fellows, the Andrew Lockett Memorial Fund Thesis award from the Massachusetts Institute of Technology, and the Tingye Li Innovation Prize from Optica.