Whispering Gallery Mode Yellow Lasing From Dy³⁺ -Doped Silica Glass Microspheres

Whispering-gallery-mode (WGM) microresonators with a high Q-factor, such as glass microspheres, enable the development of low-threshold and narrow linewidth lasers [1]. So far, the research on such coherent light sources mainly focused on near-infrared emission. Upconversion lasers based on this architecture has also been reported [2]. Recently, there is a constantly growing interest in lasers directly emitting visible light under pumping in the UV and blue spectral ranges, e.g., using GaN-based diode lasers. Dysprosium ions <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$(\text{Dy}^{3+})$</tex> are appealing because of their yellow emission, Fig. 1(a), and Dy lasers can address the so-called “green gap” problem of semiconductor laser sources [3]. We report on WGM yellow lasing from a <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{Dy}^{3+}$</tex> -doped silica glass microsphere.