Demonstration of ultralow-threshold 2 micrometer microlasers on chip

Abstract

We demonstrate ultralow-threshold thulium-doped, as well as thulium-holmium-codoped, microtoroid lasers on silicon chips, operating at the wavelength of around 2 m. High quality factor whispering gallery mode (WGM) microtoroid cavities with proper thulium and holmium concentrations are fabricated from the silica sol-gel films. The highly confined WGMs make the microcavity lasers operate with ultralow thresholds, approximately 2.8 W and 2.7 W for the thulium-doped and the thulium-holmium-codoped microlasers, respectively. microcavity, microlaser, integrated optics devices PACS number(s): 42.55.Sa, 42.55.Rz, 42.82.Bq Citation: Fan H B, Jiang X S, Ding Y, et al. Demonstration of ultralow-threshold 2 micrometer microlasers on chip.

Up-Conversion Luminescence and C-Band Laser in Er3+-Doped Fluorozirconate Glass Microsphere Resonator

“…The existence of the fundamental WG mode (|m| = l) makes it relatively easy to absorb more pump energy and thus lowers the lasing threshold. Single mode lasing can therefore be achieved using a lower pump power when the taper is physically contacted at the microsphere equator [31], [32]. Mode competition was observed and the higher order polar laser modes (l > |m|) were excited as the coupling taper was placed far from the equatorial plane in a corresponding region [33].…”

The nonlinear effects and applications of gain doped whispering-gallery mode cavities

“…Based on the gain medium in the microcavity, it is possible to create lasers at relatively low pump power. The low threshold lasers with a threshold of 2 to 3 μW are achieved in WGM microcavities and even deformable cavities doped with Er 3+ , Tm 3+ , Yb 3+ , Ho 3+ [27,28,60]. As previously mentioned, Yb 3+ can be used as a sensitizer for Er 3+ to prepare Er 3+ /Yb 3+ co-doped single-mode or multi-mode lasers with 1550 nm wavelength [13].…”

Optically pumped Milliwatt Whispering-Gallery microcavity laser

“…YAG crystal can be doped with various rare-earth elements, allowing for laser emission across a broad range of wavelengths, including ~2.9 μm (Er) 40 , 2 μm (Tm) 41 , 1.6–1.4 μm (Cr) 42 , 1.3 μm (Nd) 43 , 1.06 μm (Nd) 44 , and 1.03 μm (Yb) 45 . Notably, the Nd: YAG crystal, with its four-level laser system, exhibits a remarkably low lasing threshold and is well-suited for on-chip applications, nonlinear optics, and biosensors, which has been extensively discussed as an on-chip light source based on waveguides 46 – 48 . The main challenge to its application as WGM microlaser is to extract the membrane structure from the doped YAG bulk crystal.…”