35-fs diode-pumped mode-locked ytterbium-doped multi-component alkaline-earth fluoride laser

Area of Science:

• Laser physics
• Materials science
• Ultrafast optics

Background:

• Mode-locked lasers are crucial for generating ultrashort optical pulses.
• Alkaline-earth fluoride crystals doped with ytterbium (Yb) are promising laser gain media.
• Achieving femtosecond pulse durations requires precise control over laser parameters and components.

Purpose of the Study:

• To demonstrate direct generation of sub-40 femtosecond (fs) pulses from a diode-pumped laser.
• To investigate the performance of a novel ytterbium-yttrium codoped multi-component alkaline-earth fluoride crystal.
• To achieve record-short pulse durations in Yb-doped alkaline-earth fluoride lasers.

Main Methods:

• Utilized a diode-pumped mode-locked laser setup.
• Employed an ytterbium-yttrium codoped multi-component alkaline-earth fluoride crystal (Yb,Y:(Ca,Sr)F2) as the gain medium.
• Incorporated a semiconductor saturable absorber mirror (SESAM) for mode-locking.

Main Results:

• Successfully generated soliton pulses as short as 35 fs at 1056.7 nm.
• Achieved an average output power of 182 mW at a repetition rate of ~65.7 MHz.
• Increased output power to 322 mW (49 fs pulse duration) with 32.4% optical efficiency.

Conclusions:

• The Yb,Y:(Ca,Sr)F2 laser system is capable of directly generating ultrashort femtosecond pulses.
• This work represents the shortest pulses reported from a Yb-doped alkaline-earth fluoride crystal laser.
• The demonstrated performance highlights the potential of these materials for ultrafast laser applications.