On-chip fabrication of air-bubble-containing Nd3+-doped tellurite glass microsphere for laser emission

Tetsuo Kishi,Tetsuji Yano,Shuichi Shibata,Tsutaru Kumagai

doi:10.1063/1.4769888

Abstract

We fabricated an air-bubble-containing glass microsphere on a substrate by using localized heating technique. Nd3+-doped tellurite glass cullets on a substrate were melted by a CW-Ti:sapphire laser at the wavelength of 810 nm and with the power density of more than 4.8 MW/cm2 to obtain tellurite glass microspheres with the diameter of 5 to 200 μm. The localized heating technique using laser is useful to form a bubble at a certain place in the microsphere. Both air-bubble-containing and bubble-free spheres showed lasing actions at around the wavelength of 1065 nm. The average laser thresholds of the air-bubble-containing and bubble-free microspheres with the size of 20-50 μm were 0.78 mW and 5.25 mW, respectively.

Highlights

It is difficult to fabricate micrometer-size spheres having high sphericity and very smooth surface on silica glass or silicon substrate, which are commonly used for optical devices, because the shape of glass droplet on substrate is strongly affected by the wetting property of the substrate by the molten glass
The Nd3+-doped tellurite glass cullet on a silica glass substrate was placed on an XY translation stage under an optical microscope in an air
The samples were observed by an optical microscope (OM) and a scanning electron microscope (SEM) in order to know their shape and surface roughness

Summary

Introduction

Micrometer-size spheres have received considerable attentions for many years mainly because of their versatility in micro-optical system for microlasers,[1,2,3] microamplifiers,[4] nonlinear optical devices[5,6] and chemical/bio sensors.[7,8] The microspheres for optical resonators with high-quality factor were prepared by heating the end of a glass fiber[1,2,3,4,5,6,7,8] and glass cullets in an air.[9]. On-chip fabrication of air-bubble-containing Nd3+-doped tellurite glass microsphere for laser emission -doped tellurite glass microsphere laser via a cascade process

Results

Conclusion