All-optical tuning of ultrahigh Q-factor microsphere resonators with graphite coating

Area of Science:

• Photonics and Optical Engineering
• Materials Science

Background:

• Achieving large-scale, fast tuning of microsphere resonators while preserving ultrahigh Q-factors is essential for advanced optical applications.
• Existing tuning methods may be complex, costly, or compromise resonator quality.

Purpose of the Study:

• To develop a simple, low-cost system for all-optical tuning of ultrahigh Q-factor microsphere resonators.
• To investigate the feasibility of using graphite coating for efficient optical control of resonator properties.

Main Methods:

• Microsphere resonators were fabricated from single-mode optical fibers using the arc discharge method.
• The microspheres were coated with a graphite layer.
• All-optical tuning was achieved by irradiating the graphite coating with a control laser, inducing thermal expansion.

Main Results:

• The graphite-coated microsphere resonator demonstrated effective all-optical tuning.
• A responsivity of 96 pm/mW was achieved for all-optical tuning with a control laser power up to 10 mW.
• The system maintained the ultrahigh Q-factor of the resonator.

Conclusions:

• The graphite-coated microsphere resonator offers a simple, low-cost, and easily manufactured solution for fast all-optical tuning.
• This approach successfully combines ultrahigh Q-factor with efficient optical tunability.
• The developed system is promising for various applications requiring precise control of optical resonators.