Reconfigurable directional lasing modes in cavities with generalized PT symmetry

Area of Science:

• Physics
• Electrical Engineering
• Photonics

Background:

• Parity-time (PT) symmetry offers unique properties for wave manipulation.
• Gyrotropic elements introduce non-reciprocity, crucial for directional effects.
• Unidirectional lasing is highly desirable for various applications, including optical communications and signal processing.

Purpose of the Study:

• To introduce a novel family of generalized PT-symmetric cavities incorporating gyrotropic elements.
• To establish the theoretical conditions for the existence of reconfigurable unidirectional lasing modes within these cavities.
• To experimentally validate the proposed concept using a practical radio-frequency electronic circuit.

Main Methods:

• Theoretical derivation of conditions for PT-symmetric modes in cavities with gyrotropy.
• Development of a generalized cavity model including non-reciprocal elements.
• Design and simulation of a simple electronic circuit mimicking the cavity's behavior.
• Experimental implementation and testing of the electronic circuit in the radio-frequency spectrum.

Main Results:

• Successful derivation of the existence conditions for unidirectional lasing modes.
• Demonstration of reconfigurability in the lasing direction.
• Experimental validation of the PT-symmetric cavity concept in the radio-frequency domain.
• Confirmation of the feasibility of using gyrotropic elements for controlled unidirectional emission.

Conclusions:

• Generalized PT-symmetric cavities with gyrotropic elements enable reconfigurable unidirectional lasing.
• The proposed theoretical framework is experimentally verifiable.
• This work opens avenues for novel non-reciprocal devices and systems in RF and potentially optical domains.