All-Optical Tunable Microlaser Based on an Ultrahigh‑Q Erbium-Doped Hybrid Microbottle Cavity

• Published in: ACS photonics Vol. 5; no. 9; pp. 3794 - 3800
• Main Authors: Zhu, Song, Shi, Lei, Xiao, Bowen, Zhang, Xinliang, Fan, Xudong
• Format: Journal Article
• Language: English
• Published: American Chemical Society 19-09-2018
• Subjects: microlasers; iron oxide nanoparticles; whispering gallery modes; all-optical tuning; erbium-doped
• ISSN: 2330-4022; 2330-4022
• DOI: 10.1021/acsphotonics.8b00838

An all-optical tunable microlaser based on the ultrahigh-quality (Q)-factor erbium-doped hybrid microbottle cavity is proposed and experimentally demonstrated for the first time. All-optical wavelength tunability of the silica microcavity laser is a very attractive feature and has been rarely reported. By using an improved doping method, the erbium-doped silica microbottle cavity with a Q factor of 5.2 × 107 in the 1550 nm band is obtained, which is higher than the previous work based on the conventional sol–gel method. Through nonresonant pump in the 980 nm band, a lasing threshold of 1.65 mW is achieved, which is lower than all those realized through the same pump method. Besides, iron oxide nanoparticles are coated on the tapered area by doping them in the ultraviolet curing adhesive in order to precisely control the coating area, which enables the hybrid microcavity to maintain the ultrahigh Q factor and possess large tunability. By feeding the control light through the axial direction of the microbottle cavity, the lasing wavelength is all-optically tuned with a range of 4.4 nm, which is larger than the reported doped silica microcavity lasers. This work has great potential in applications such as optical communications, sensing, and spectroscopy.