High-Q microfluidic cavities in silicon-based two-dimensional photonic crystal structures.

Area of Science:

• Photonics
• Materials Science
• Microfluidics

Background:

• Photonic crystal slab waveguides are crucial for integrated optics.
• Microfluidic control offers a pathway to tune optical properties.
• Achieving high-quality factor (Q) cavities is essential for many photonic applications.

Purpose of the Study:

• To demonstrate postprocessed microfluidic double-heterostructure cavities in silicon-based photonic crystal slab waveguides.
• To investigate the impact of selective fluid infiltration on cavity performance.
• To achieve high Q factors in microfluidic photonic crystal cavities.

Main Methods:

• Fabrication of silicon-based photonic crystal slab waveguides.
• Postprocessing using selective fluid infiltration of air holes with a glass microtip.
• Probing of microcavities via evanescent coupling from a silica nanowire.

Main Results:

• Successfully realized postprocessed microfluidic double-heterostructure cavities.
• Demonstrated local tuning of the photonic crystal's average refractive index via fluid infiltration.
• Measured an intrinsic quality factor of 57,000 for the microcavities.

Conclusions:

• The demonstrated microfluidic cavities offer a promising platform for tunable photonic devices.
• The achieved quality factor represents a significant advancement in microfluidic photonic crystal cavities.
• This technique enables precise control over optical properties in photonic integrated circuits.