Chip-scale modulation-free laser stabilization using vacuum-gap micro-Fabry-Pérot cavity.

A silicon photonic chip with a vacuum-gap micro-Fabry-Pérot cavity achieves a fractional frequency instability of 1.45×10⁻¹² at 1 second, enabling scalable ultrastable lasers.

• Why it matters: Stable, narrow-linewidth lasers are vital for atomic clocks and precision sensing, but current high-performance stabilization methods are difficult to scale and deploy outside laboratories.
• What they did: The team developed a cavity-coupled interferometric laser stabilization technique on a wafer-scale silicon photonic chip, integrating a high-Q optical cavity operating in air.
• The result: This approach reduces the laser linewidth by over 38 times and suppresses frequency noise by 30 decibels at 10 Hz, paving the way for portable, high-stability laser systems.