Intracavity vector vortex pattern generation in a diode-pumped Tm:Y₂O₃ ceramic laser with X-type folded resonator

Area of Science:

• Laser Physics
• Optical Engineering
• Materials Science

Background:

• Vector vortex beams offer unique polarization and orbital angular momentum properties.
• Mid-infrared lasers are crucial for various applications, including spectroscopy and free-space communications.
• Isotropic ceramic gain media present advantages for laser development.

Purpose of the Study:

• To demonstrate direct generation of vector vortex beams in the 2 µm wavelength range using isotropic ceramics.
• To explore the switching capabilities between different polarized vortex beams.
• To investigate the potential for structured light field manipulation in the mid-infrared.

Main Methods:

• Utilized a diode-pumped Tm:Y2O3 ceramic laser with an X-folded cavity.
• Employed off-axis non-collinear hybrid pumping and aperture control.
• Generated and characterized four distinct polarized vortex beams (linearly, elliptically, anti-radially, anti-azimuthally polarized).

Main Results:

• Successfully generated vector vortex beams with a central wavelength of ~2050 nm and orbital angular momentum (OAM) of ±1ℏ.
• Achieved high beam quality (M² factors 2.03–2.3), stability (RMS 0.47%), purity (SNR 16.7 dB), and output power (up to 242 mW).
• Demonstrated generation of vortex arrays and verified their properties through simulation and experiment.

Conclusions:

• This work presents the first laser directly generating vector vortex beams using isotropic ceramics at 2 µm.
• Establishes a new paradigm for structured light manipulation in the mid-infrared using ceramic gain media.
• Highlights the potential of this technology for advanced optical applications.