Lasing action in a strongly coupled silicon nanowire pair

Area of Science:

• Photonics and Nanotechnology
• Optoelectronics

Background:

• High-index dielectric nanostructures offer low absorption losses for nanoscale lasing.
• Weak near-fields in isolated dielectric cavities limit their use as low-threshold integrated on-chip laser sources.

Purpose of the Study:

• To demonstrate lasing action in a coupled silicon nanowire pair.
• To investigate the factors influencing the quality factor (Q) and threshold power of the nanolasers.

Main Methods:

• Fabrication of a silicon nanowire pair with a 32 nm gap on a silicon-on-insulator platform.
• Coating the nanowires with a dye-doped shell.
• Experimental characterization of lasing performance, including wavelength, FWHM, and pumping power threshold.

Main Results:

• Lasing action achieved in the silicon nanowire pair at 529 nm with a Full Width at Half Maximum (FWHM) of 0.6 nm.
• Quality factor (Q) is significantly influenced by the coupling between nanowires, dependent on gap size, nanowire width, and dye thickness.
• A low pumping power threshold of approximately 34 µW/cm² was experimentally realized.

Conclusions:

• The coupled silicon nanowire pair acts as an effective nanolaser cavity.
• The strategy utilizes established silicon planar processes, enabling practical integrated nanolasers.
• Potential applications in advanced photonic circuits and on-chip optical functionalities.