Cascaded Raman lasing in packaged high quality As₂S₃ microspheres

Area of Science:

• Optics and Photonics
• Materials Science

Background:

• High-Q microspheres are crucial for nonlinear optical processes.
• Arsenic trisulfide (As₂S₃) exhibits significant Raman scattering properties.

Purpose of the Study:

• To investigate cascaded stimulated Raman scattering in As₂S₃ microspheres.
• To demonstrate a self-frequency locking laser using these microspheres.

Main Methods:

• Fabrication of high-Q As₂S₃ microspheres.
• Utilizing a self-frequency locking laser setup.
• Measuring threshold pump power and Raman emission orders.

Main Results:

• Observed cascaded Raman lasing up to the 5th order for 1557 nm pump.
• Achieved cascaded Raman lasing up to the 3rd order for 1880 nm pump.
• Demonstrated sub-milliwatt threshold pump power consistent with coupled mode theory.

Conclusions:

• High-Q As₂S₃ microspheres enable efficient cascaded Raman lasing.
• The self-frequency locking laser setup is effective for generating multi-order Raman emission.
• Low threshold power indicates practical potential for integrated photonic devices.