Low‐Threshold Wavelength‐Switchable Organic Nanowire Lasers Based on Excited‐State Intramolecular Proton Transfer

TLDR

Coherent light signals generated at the nanoscale are crucial to the realization of photonic integrated circuits, and self‑assembled organic dye nanowires can serve as both gain medium and resonant cavity for miniaturized lasers. Excited‑state intramolecular proton transfer (ESIPT) provides a four‑level system that facilitates population inversion, and the lasing wavelength can be reversibly switched by conformational conversion of the excited keto form. Low‑power driven lasing was achieved in proton‑transfer nanowires with optimized ESIPT, yielding single‑mode lasing with a very low threshold due to high gain and low loss.

Abstract

Coherent light signals generated at the nanoscale are crucial to the realization of photonic integrated circuits. Self-assembled nanowires from organic dyes can provide both a gain medium and an effective resonant cavity, which have been utilized for fulfilling miniaturized lasers. Excited-state intramolecular proton transfer (ESIPT), a classical molecular photoisomerization process, can be used to build a typical four-level system, which is more favorable for population inversion. Low-power driven lasing in proton-transfer molecular nanowires with an optimized ESIPT energy-level process has been achieved. With high gain and low loss from the ESIPT, the wires can be applied as effective FP-type resonators, which generated single-mode lasing with a very low threshold. The lasing wavelength can be reversibly switched based on a conformation conversion of the excited keto form in the ESIPT process.