Cryogenically-cooled Yb:YGAG ceramic mode-locked laser

Area of Science:

• Laser Physics
• Materials Science
• Solid-State Lasers

Background:

• Yb:YGAG (Ytterbium-doped Yttrium Gallium Aluminum Garnet) ceramics offer potential for ultrashort pulse generation due to their broad emission spectrum.
• Cryogenic cooling enhances laser performance by narrowing spectral linewidths, but can limit bandwidth.
• Comparing Yb:YGAG to Yb:YAG (Yttrium Aluminum Garnet) at low temperatures is crucial for understanding their suitability for advanced laser applications.

Purpose of the Study:

• To investigate the performance of a liquid-nitrogen-cooled, SESAM mode-locked Yb:YGAG ceramic laser.
• To evaluate the ultrashort pulse generation capabilities of Yb:YGAG at low temperatures.
• To explore the continuous-wave operation and wavelength tunability of Yb:YGAG ceramics at 80 K.

Main Methods:

• Fabrication and characterization of a SESAM mode-locked Yb:YGAG ceramic laser.
• Operation at liquid nitrogen temperature (77 K).
• Measurement of pulse duration, repetition rate, and wavelength.

Main Results:

• A stable pulse train with a 119-MHz repetition rate at 1026 nm was achieved.
• Ultrashort pulses with a duration of 2.4 ps were measured, significantly shorter than those from cryogenically-cooled Yb:YAG.
• Laser performance in continuous-wave operation and wavelength tunability at 80 K was investigated.

Conclusions:

• Yb:YGAG ceramic lasers are highly suitable for ultrashort pulse generation, outperforming Yb:YAG at low temperatures.
• The broad emission spectrum of Yb:YGAG at low temperatures is key to achieving shorter pulse durations.
• Further investigation into continuous-wave and tunable operation of Yb:YGAG ceramics at cryogenic temperatures is warranted.