High-Q and highly reproducible microdisks and microlasers

Area of Science:

• Photonics
• Materials Science
• Nanotechnology

Background:

• High-quality (Q) factor microdisks are crucial for integrated photonic circuits and biological sensors.
• Microdisk performance is highly sensitive to surface roughness, with surface-tension-formed structures offering superior Q factors.
• Fabricating high-Q microdisks from materials like silicon often relies on complex electron-beam lithography.

Purpose of the Study:

• To demonstrate a robust, cost-effective, and reproducible technique for fabricating ultrahigh-Q microdisks.
• To overcome limitations of traditional fabrication methods for photonic materials.
• To enable controllable designs for micro-resonators and their applications.

Main Methods:

• Utilizing silica microtoroids as masks to replicate ultrasmooth boundaries.
• Employing anisotropic dry etching to transfer the microtoroid shape into photoresist.
• Applying the technique to various materials, including polymers and silicon, for passive and active devices.

Main Results:

• Achieved experimentally recorded Q factors as high as 1.5 × 10^6 for passive microdisks.
• Demonstrated ultrahigh-Q microdisk lasers with a linewidth of 8 pm, limited by the spectrometer.
• Successfully fabricated high-Q deformed microdisks with controllable optical emission properties.
• Fabricated silicon microdisks with Q factors exceeding 10^6.

Conclusions:

• The developed technique offers a significant advancement in fabricating ultrahigh-Q microdisks.
• This method provides a pathway for creating high-performance micro-resonators for diverse photonic applications.
• The versatility of the technique across different materials opens new possibilities in integrated photonics and sensing.