Low-Threshold Microlasers Based on Holographic Dual-Gratings

Area of Science:

• Photonics and Laser Technology
• Materials Science
• Quantum Dot Applications

Background:

• Microlaser performance optimization is crucial for advanced photonic applications.
• Distributed feedback (DFB) lasers are promising for electrically pumped microlasers.
• Cavity design freedom is limited in conventional DFB lasers.

Purpose of the Study:

• To design a holographic dual-grating structure for improved DFB microlaser performance.
• To balance optical feedback and cavity output for lower lasing thresholds.
• To leverage the stability of colloidal quantum dots in microlaser applications.

Main Methods:

• Fabrication of a colloidal quantum dot film with first-order (210 nm) and second-order (420 nm) gratings using spin coating and interference lithography.
• Design and analysis of a holographic dual-grating system to control laser feedback and output.
• Characterization of lasing threshold and stability of the fabricated microlaser.

Main Results:

• The holographic dual-grating laser achieved a lasing threshold nearly half that of conventional DFB lasers.
• The dual-grating design effectively balanced feedback and cavity output.
• The microlaser demonstrated high stability due to the photobleaching resistance of colloidal quantum dots.

Conclusions:

• Holographic dual-grating technology offers a significant advancement in DFB microlaser design.
• This approach enables lower threshold operation and enhanced device stability.
• Colloidal quantum dots are suitable materials for robust and efficient microlaser fabrication.