Low-noise, 2-W average power, 112-fs Kerr-lens mode-locked Ho:CALGO laser at 2.1 µm

Area of Science:

• Laser Physics
• Solid-State Lasers
• Ultrafast Optics

Background:

• Mode-locked lasers are crucial for generating ultrashort optical pulses.
• Thulium (Tm³⁺) and Holmium (Ho³⁺) doped lasers are important for mid-infrared applications.
• Achieving high average power with ultrashort pulses in bulk lasers remains a challenge.

Purpose of the Study:

• To demonstrate a high-performance Ho:CALGO bulk laser.
• To achieve high average power and ultrashort pulse durations at 2.1 µm.
• To characterize the noise properties of the developed laser system.

Main Methods:

• In-band pumping of a soft-aperture Kerr-lens mode-locked Ho³⁺-doped CaGdAlO₄ (Ho:CALGO) bulk laser.
• Utilized a 2.1 µm laser wavelength.
• Characterized average power, pulse duration, repetition rate, relative intensity noise, and timing jitter.

Main Results:

• Generated 2 W of average power with 112 fs pulses at a 91 MHz repetition rate.
• Achieved the highest average power for a 100-fs class mode-locked Tm³⁺ or Ho³⁺ doped bulk laser.
• Demonstrated excellent noise properties: 0.02% integrated relative intensity noise and 950 fs timing jitter.

Conclusions:

• The Ho:CALGO laser represents a significant advancement in ultrafast laser technology.
• The combination of high power, short pulses, and low noise makes it ideal for various 2.1 µm applications.
• This work sets a new benchmark for mode-locked Tm³⁺/Ho³⁺ doped bulk lasers.