Coincidence detection of inharmonic pulses in a nonlinear crystal

TL;DR

This paper demonstrates how nonlinear optical processes can mimic neural coincidence detection, revealing a transition from perception-like to motor-like frequency regimes in pulse trains.

Contribution

It introduces an experimental setup that explores the transition between perception and motor neural analogs using nonlinear optical pulse generation.

Findings

Pulse frequency follows classical virtual pitch perception when input pulses are broad.

Lower frequencies emerge with narrower input pulses, akin to motor neural responses.

Systematic exploration of transition between perception and motor regimes in nonlinear optics.

Abstract

Two trains of light pulses at periods that are equally shifted from the harmonics of a missing fundamental, are combined in a nonlinear crystal. As a result of a noncollinear phase matched second order nonlinear generation, a new train of pulses is obtained. When the temporal width of the input pulses is large, the frequency of the resulting pulse train follows the observations from classical experiments on the perception of virtual pitch by the brain. On the other hand, when the width of the input pulses is small, the generated pulse train exhibits much lower frequencies, analogous to those observed in the motor neural system. Our experimental set up allows us to explore, systematically and continuously, the transition between these two regimes, while at the same time demonstrate that coincidence detection in quadratic nonlinear systems has functionalities similar to those observed in the nervous system.