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Properties of fluoride microresonators for mid-IR applications
Optics Letters
|May 14, 2016
Summary
We developed crystalline fluoride microresonators for mid-infrared applications. Magnesium fluoride (MgF2) resonators achieved a high Q-factor of 8.3×10^6 at 4.58 μm, limited by multiphoton absorption.
Area of Science:
- Materials Science
- Optical Engineering
- Solid State Physics
Background:
- Crystalline fluoride microresonators are crucial for mid-infrared (mid-IR) applications.
- Whispering gallery mode resonators offer high optical confinement.
- Understanding loss mechanisms is key to improving resonator performance.
Purpose of the Study:
- To fabricate and characterize crystalline fluoride microresonators (BaF2, CaF2, MgF2) for mid-IR applications.
- To investigate the impact of fabrication processes, impurities, and surface water on resonator performance.
- To measure mid-IR optical losses, particularly those from multiphoton absorption.
Main Methods:
- Fabrication of whispering gallery mode resonators using BaF2, CaF2, and MgF2 crystals.
- Measurement of quality factors (Q-factors) at 1.56 μm and 4.58 μm.
- Analysis of optical loss mechanisms, including multiphoton absorption.
Main Results:
- MgF2 resonators demonstrated a room temperature Q-factor of 8.3×10^6 at 4.58 μm.
- Multiphoton absorption was identified as the primary limiting factor for mid-IR optical losses in MgF2 resonators.
- The study highlighted the influence of post-fabrication processing, impurities, and surface water on resonator performance.
Conclusions:
- Crystalline fluoride microresonators, especially MgF2, show significant promise for mid-IR applications.
- Optimizing fabrication and minimizing impurities are essential for achieving higher Q-factors.
- Multiphoton absorption is a critical consideration for high-performance mid-IR resonators.
