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Turkish Journal of Physics

Abstract

Parity-time symmetry (PTS) has emerged as a powerful strategy for engineering single-mode lasers with enhanced mode selectivity. In this work, we present a systematic numerical study comparing two classes of non-Hermitian micro-laser designs: PTS and quasi-PTS (q-PTS). Using lithographically defined vertical-cavity surface-emitting lasers (Li-VCSELs) as our platform, we show that q-PTS VCSELs offer superior transverse mode discrimination compared to their PTS counterparts. This advantage arises from the unique coupling mechanism in q-PTS architectures, where the fundamental mode preserves its low-loss nature. In contrast, PTS VCSELs require the second-order mode to remain in the PTS phase while the fundamental mode is in the broken PTS phase, thus narrowing the single-mode operating range. Our findings highlight q-PTS as a promising approach for extending single-mode VCSEL operation, paving the way for non-Hermitian strategies in high-power, single-mode devices.

Author ORCID Identifier

ABDULLAH DEMİR: 0000-0003-4678-0084

DOI

10.55730/1300-0101.2776

Keywords

semiconductor laser, VCSEL, non-Hermitian photonics, parity-time symmetry, mode selectivity

First Page

63

Last Page

71

Publisher

The Scientific and Technological Research Council of Türkiye (TÜBİTAK)

Creative Commons License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.

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