Ultra-low Threshold Titanium doped sapphire Whispering-gallery Laser

Abstract

Titanium doped sapphire (Ti:sapphire) is a laser gain material with broad gain bandwidth benefiting from the material stability of sapphire. These favorable characteristics of Ti:sapphire have given rise to femtosecond lasers and optical frequency combs. Shaping a single Ti:sapphire crystal into a millimeter sized high quality whispering gallery mode resonator ($Q\sim 10^8$) reduces the lasing threshold to 14.2 mW and increases the laser slope efficiency to 34%. The observed lasing can be both multi-mode and single-mode. This is the first demonstration of a Ti:sapphire whispering-gallery laser. Furthermore, a novel method of evaluating the gain in Ti:sapphire in the near infrared region is demonstrated by introducing a probe laser with a central wavelength of 795 nm. This method results in decreasing linewidth of the modes excited with the probe laser, consequently increasing their $Q$. These findings open avenues for the usage of whispering gallery mode resonators as cavities for the implementation of compact Ti:sapphire lasers. Moreover, Ti:sapphire can also be utilized as an amplifier inside its gain bandwidth by implementing a pump-probe configuration.

arXiv commentMain text (13 pages, 7 figures) Supplemental document (11 pages, 9 figures)

References in corpus (12)

• High-Power Directional Emission from Microlasers with Chaotic Resonators
• Ray and wave chaos in asymmetric resonant optical cavities
• Brillouin Lasing with a CaF_2 Whispering Gallery Mode Resonator
• Nonlinear and Quantum Optics with Whispering Gallery Resonators
• Dramatic Shape Sensitivity of Directional Emission Patterns from Similarly Deformed Cylindrical Polymer Lasers
• Fresnel filtering in lasing emission from scarred modes of wave-chaotic optical resonators
• Whispering Gallery Mode Resonator Stabilized Narrow Linewidth Fiber Loop Laser
• Efficient upconversion of sub-THz radiation in a high-Q whispering gallery resonator
• Theory of the spatial structure of non-linear lasing modes
• Sub-kHz lasing of a CaF_2 Whispering Gallery Mode Resonator Stabilized Fiber Ring Laser
• Quantitative Verification of Ab Initio Self-consistent Laser Theory
• Estimation of Purcell factor from mode-splitting spectra in an optical microcavity

Cited by in corpus (4)

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• Distance calibration via Newton's rings in yttrium lithium fluoride whispering gallery mode resonators
• Microwave-optical double resonance in a erbium-doped whispering-gallery-mode resonator