A Tunable Optofluidic Microlaser in a Photostable Conjugated Polymer

Area of Science:

• Optofluidics
• Biophotonics
• Materials Science

Background:

• Optofluidic lasers are crucial for biological sensing and medical diagnostics.
• Current gain materials like fluorescent dyes have limited photostability, affecting reliability and sensitivity.

Purpose of the Study:

• To demonstrate an optofluidic microlaser with enhanced stability and tunable lasing.
• To address the limitations of traditional gain materials in optofluidic devices.

Main Methods:

• Fabrication of an ultrahigh-Q whispering-gallery microcavity.
• Filling the microcavity with a biocompatible conjugated polymer as the gain medium.
• Characterization of lasing properties, including threshold, stability, and tunability.

Main Results:

• Achieved an ultralow lasing threshold of 7.8 µJ cm^-2.
• Demonstrated superior photostability of the conjugated polymer compared to Nile red dye.
• Showcased mechanical tunability of lasing frequency over approximately 2 nm.

Conclusions:

• The developed optofluidic microlaser offers improved stability and performance for biological applications.
• Biocompatible conjugated polymers are promising gain materials for next-generation optofluidic sensors.
• Mechanical tunability provides an additional control parameter for optofluidic laser systems.