Structural Phase Transitions of Optical Patterns in Atomic Gases with Microwave Controlled Rydberg Interactions

TL;DR

This paper proposes a method to induce and control optical pattern formation and phase transitions in cold Rydberg atomic gases using microwave dressing, enabling flexible manipulation of self-organized light structures for potential optical applications.

Contribution

It introduces a novel scheme to actively control optical pattern formation and phase transitions in Rydberg gases via microwave-induced nonlocal Kerr nonlinearities, expanding the possibilities for optical self-organization.

Findings

Microwave dressing enhances and tunes nonlocal Kerr nonlinearity.

Pattern transitions from hexagonal to square lattices with microwave control.

Formation of nonlocal optical solitons through modulation instability.

Abstract

Spontaneous symmetry breaking and formation of self-organized structures in nonlinear systems are intriguing and important phenomena in nature. Advancing such research to new nonlinear optical regimes is of much interest for both fundamental physics and practical applications. Here we propose a scheme to realize optical pattern formation in a cold Rydberg atomic gas via electromagnetically induced transparency. We show that, by coupling two Rydberg states with a microwave field (microwave dressing), the nonlocal Kerr nonlinearity of the Rydberg gas can be enhanced significantly and may be tuned actively. Based on such nonlocal Kerr nonlinearity, we demonstrate that a plane-wave state of probe laser field can undergo a modulation instability (MI) and hence spontaneous symmetry breaking, which may result in the emergence of various self-organized optical patterns. Especially, we find that a hexagonal lattice pattern (which is the only optical pattern when the microwave dressing is absent) may develop into several types of square lattice ones when the microwave dressing is applied; moreover, as a outcome of the MI the formation of nonlocal optical solitons is also possible in the system. Different from earlier studies, the optical patterns and nonlocal optical solitons found here can be flexibly manipulated by adjusting the effective probe-field intensity, nonlocality degree of the Kerr nonlinearity, and the strength of the microwave field. Our work opens a route for versatile controls of self-organizations and structural phase transitions of laser light, which may have potential applications in optical information processing and transmission.