Stable and accurate characterization of optical microcavity using linear frequency modulation and thermal locking.

Area of Science:

• Photonics and Optical Engineering
• Cavity Quantum Electrodynamics
• Materials Science

Background:

• Ultra-low-loss optical microcavities are crucial for advanced photonic applications.
• Thermal effects from probe light can significantly impact the accuracy of microcavity characterization.
• Existing methods struggle with precise measurements due to thermal instability.

Purpose of the Study:

• To develop a novel scheme for accurate characterization of optical microcavity performance.
• To mitigate the detrimental effects of thermal loading during measurements.
• To enable stable and precise determination of quality factor (Q) and coupling regimes.

Main Methods:

• Modulating probe light with radio frequency (RF) signals applied to a Mach-Zehnder modulator (MZM).
• Utilizing the carrier wave for thermal locking of the microcavity.
• Scanning the first-order sideband across resonance frequencies with Hz-level precision.
• Combining thermal locking with fine frequency stepping for enhanced stability.

Main Results:

• Demonstrated a scheme for stable and accurate microcavity performance testing.
• Successfully overcame thermal effects that compromise characterization accuracy.
• Enabled both stationary and dynamic measurements with exceptional precision.
• Provided a robust method for determining quality factor (Q) and coupling regimes.

Conclusions:

• The proposed RF modulation scheme offers a significant advancement in optical microcavity characterization.
• This technique ensures high accuracy and stability, essential for research and development in photonics.
• The method is suitable for precise measurements of ultra-low-loss microcavities, paving the way for new applications.