Efficient few-cycle Yb-doped laser oscillator with Watt-level average power

Area of Science:

• Laser Physics
• Ultrafast Optics
• Materials Science

Background:

• Ultrafast bulk laser oscillators using Yb-doped materials are limited by low efficiency and output power.
• Standard collinear pumping schemes suffer from spectral and dispersion issues caused by dichroic mirrors, especially for few-cycle pulses.

Purpose of the Study:

• To introduce and validate a novel cross-polarization pumping scheme for Yb-doped ultrafast bulk lasers.
• To overcome the performance limitations of conventional pumping methods.

Main Methods:

• Developed a pumping scheme using a mirror highly transmissive for p-polarized pump light and highly reflective for s-polarized laser light.
• Implemented this scheme in a soft-aperture Kerr-lens mode-locked Yb:CALGO bulk laser oscillator.
• Tested different configurations to optimize power and efficiency.

Main Results:

• Achieved 22-fs soliton pulses with 729 mW average output power and 25% optical-to-optical efficiency.
• Demonstrated 31-fs pulses at 1.63 W average output power with 36.6% optical-to-optical efficiency.
• Confirmed the detrimental effect of standard dichroic mirrors in collinear pumping.

Conclusions:

• The novel cross-polarization pumping scheme effectively enhances efficiency and output power in Yb-doped ultrafast bulk lasers.
• This approach is suitable for generating high-power, few-cycle pulses and applicable to other gain materials.
• The method offers potential for compact and cost-efficient laser systems.