Controllable Polarization of Lasing Emission From a Polymer Microfiber Laser

Area of Science:

• Optics and Photonics
• Materials Science

Background:

• Controllable polarization in microlasers is essential for advanced optical applications like on-chip communications and sensors.
• Whispering gallery mode (WGM) lasers offer high quality (Q) factors but often lack polarization control.

Purpose of the Study:

• To report a high-Q, low-threshold polymer microfiber laser with controllable output polarization.
• To demonstrate the ability to achieve desired laser emission polarization through external stimuli.

Main Methods:

• Fabrication of a dye-doped polymer microfiber using a direct drawing technique.
• Optical pulse excitation of the microfiber to generate whispering gallery mode (WGM) lasing.
• Side-pumping the microfiber with the pump direction perpendicular to its axis.

Main Results:

• Achieved WGM lasing in the polymer microfiber with a high Q factor and low threshold.
• Demonstrated that the output laser polarization aligns with the pump laser polarization when pumped perpendicularly.
• Successfully switched between transverse electric (TE) and transverse magnetic (TM) modes by tuning the pump laser.
• Observed simultaneous TE and TM mode emission by altering the microfiber's orientation relative to the pump direction.

Conclusions:

• The developed polymer microfiber laser offers a viable platform for high-Q lasing with tunable polarization.
• This method provides an effective approach for creating microlasers with anticipated polarization control for optical devices.