Physical Society Colloquium

Chirped-pulse interferometry: “quantum” interference with classical light

Kevin Resch

University of Waterloo

Interference is a characteristic feature of both quantum and classical theories of light and is an indispensable tool for precision measurement. Studies of entangled quantum systems have uncovered many new interference phenomena, such as phase super-resolution and automatic dispersion cancellation, which may form the basis for superior measurement techniques. However, the requisite entangled states are difficult to create, manipulate and detect especially compared with classical states of light.

In the present talk, I will describe our efforts to develop a completely classical interferometer whose signal contains all of the advantageous features of the quantum Hong-Ou-Mandel (HOM) interferometer, but with millions of times more signal. Instead of entangled photons and coincidence detection, our interferometer uses “chirped” laser pulses and nonlinear optics. The HOM setup, with small modifications, is the basis for several other quantum interferometers. I will show how our chirped-pulse interferometer can achieve their features as well with analogous modifications. These results show that quantum and classical interference may not be as different as previously thought. Furthermore, they show how insights gained from quantum mechanics can inspire novel classical technologies.