Reconfigurable and Recyclable Low-Threshold Quasi-BIC Lasers via a Tunable polymer Coating

TL;DR

This paper presents a recyclable, low-threshold quasi-BIC laser with tunable properties achieved through a polymer coating, enabling sustainable, reconfigurable photonic devices with sensing capabilities.

Contribution

It introduces a novel recyclable quasi-BIC laser with tunable lasing modes via a polymer coating, combining low-cost fabrication and reconfigurability.

Findings

Reinforced optical confinement reduces lasing threshold.

Achieved wavelength tuning of 7.14 nm and high sensitivity for sensing.

Laser modes are reversibly tuned through coating thickness control.

Abstract

Reconfigurable and sustainable microcavity lasers are highly desirable for next-generation integrated photonics. Here, we report a recyclable, low-threshold quasi-bound state in the continuum (q-BIC) laser fabricated via low-cost, high-throughput interference lithography. By introducing a polyvinyl alcohol (PVA) coating on a dye-doped photonic crystal, we suppress out-of-plane symmetry breaking, which reinforces optical confinement and reduces the lasing threshold. The q-BIC modes are further tuned through tailoring the refractive-index of the PVA layer by using Kramers-Kronig relation via Rhodamine 6G doping, demonstrating a wavelength shift of 7.14 nm and a sensitivity of 215 nm RIU as a sensing prob. More importantly, lasing modes are reversibly tuning via precisely controlling the coating thickness. Exploiting the dissolving and re-coating process, the laser is repeatedly reconfigured while maintaining performance. This work provides a sustainable and adaptive platform for sensing and reconfigurable photonic systems.