Low threshold lasing of bubble-containing glass microspheres by non-whispering gallery mode excitation over a wide wavelength range

Journal Article · Sat Mar 21 04:00:00 EDT 2015 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4915901· OSTI ID:22399295

Kumagai, Tsutaru; Kishi, Tetsuo; Yano, Tetsuji ^[1]

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1. Department of Chemistry and Materials Science, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550 (Japan)

Bubble-containing Nd{sup 3+}-doped tellurite glass microspheres were fabricated by localized laser heating technique to investigate their optical properties for use as microresonators. Fluorescence and excitation spectra measurements were performed by pumping with a tunable CW-Ti:Sapphire laser. The excitation spectra manifested several sharp peaks due to the conventional whispering gallery mode (WGM) when the pumping laser was irradiated to the edge part of the microsphere. However, when the excitation light was irradiated on the bubble position inside the microsphere, “non-WGM excitation” was induced, giving rise to numerous peaks at a broad wavelength range in the excitation spectra. Thus, efficient excitation was achieved over a wide wavelength range. Lasing threshold excited at the bubble position was much lower than that for the excitation at the edges of the microsphere. The lowest value of the laser threshold was 34 μW for a 4 μm sphere containing a 0.5 μm bubble. Efficiency of the excitation at the bubble position with broadband light was calculated to be 5 times higher than that for the edge of the microsphere. The bubble-containing microsphere enables efficient utilization of broadband light excitation from light-emitting diodes and solar light.

• OSTI ID: 22399295
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 11 Vol. 117; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ABSORPTION SPECTRA
BUBBLES
DOPED MATERIALS
EXCITATION
FLUORESCENCE
GLASS
IRRADIATION
LASER-RADIATION HEATING
LIGHT EMITTING DIODES
MICROSPHERES
NEODYMIUM IONS
OPTICAL PROPERTIES
OPTICAL PUMPING
SAPPHIRE
VISIBLE RADIATION