End-pumped, passively Q-switched Yb:YAG double-clad waveguide laser

Area of Science:

• Laser Physics
• Materials Science

Background:

• Diode-pumped solid-state lasers offer efficient and compact laser sources.
• Passive Q-switching using saturable absorbers is a key technique for generating high-peak-power pulses.

Purpose of the Study:

• To develop a diode-pumped, double-clad Yb:YAG waveguide laser with an integrated Cr(4+):YAG saturable absorber for passive Q-switching.
• To characterize the performance of the Q-switched waveguide laser in terms of pulse energy, duration, repetition rate, and beam quality.

Main Methods:

• Fabrication of a double-clad Yb:YAG waveguide laser with an integrated Cr(4+):YAG saturable absorber.
• Pumping the waveguide laser using two 4-W polarization-coupled, broad-striped diode lasers.
• Characterization of output pulse parameters (energy, duration, repetition rate) and beam quality (M^2 values).

Main Results:

• Achieved 30-microJ pulses of 1.6-ns duration at repetition rates up to 77 kHz.
• Obtained a slope efficiency of ~50% with respect to absorbed pump power.
• Maximum output average power of 2.3 W and peak power of ~18 kW with a single-lobed output beam (M^2 values as great as 1.5x1.3).

Conclusions:

• The integrated Cr(4+):YAG saturable absorber enables efficient passive Q-switching in a diode-pumped Yb:YAG waveguide laser.
• The demonstrated laser design offers high-peak-power, short-pulse generation with good beam quality.
• Similar designs were also demonstrated for Nd:YAG waveguide lasers, indicating versatility of the approach.