High efficiency, resonantly diode pumped, double-clad, Er:YAG-core, waveguide laser.

Area of Science:

• Materials Science
• Laser Physics
• Photonics

Background:

• Development of efficient and compact laser sources is crucial for various applications.
• Crystalline waveguides offer advantages in power handling and beam quality.
• Eye-safe laser operation is desirable for applications involving human exposure.

Purpose of the Study:

• To demonstrate a highly efficient, diode-pumped, all-crystalline, double-clad waveguide laser.
• To investigate the performance of an Erbium-doped YAG (Er:YAG) crystalline core.
• To achieve laser output at eye-safe wavelengths.

Main Methods:

• Fabrication of a double-clad waveguide with an Er:YAG crystalline core and YAG cladding, over-clad with magnesium aluminum spinel.
• Resonant diode-pumping of the waveguide structure using a fiber-coupled InGaAsP/InP laser diode module at ~1532 nm.
• Characterization of output power, beam quality, and slope efficiency at ~1645 nm and ~1616.6 nm.

Main Results:

• Achieved 25.4 W of continuous-wave (CW) output power at 1645 nm with a beam quality of M² ~2.6.
• Demonstrated a slope efficiency of 56.6% with respect to absorbed pump power.
• Delivered ~8 W of output power at 1616.6 nm using a wavelength-selective cavity.

Conclusions:

• Successfully demonstrated the first crystalline Er:YAG-core, double-clad crystalline waveguide laser.
• The device exhibits high efficiency and significant output power at eye-safe wavelengths.
• This work paves the way for advanced crystalline waveguide laser development.