Diode-pumped mode-locked Tm:LuAG laser at 2  μm based on GaSb-SESAM

Area of Science:

• Laser Physics
• Materials Science

Background:

• Thulium-doped lasers (Tm:LuAG) are crucial for generating light in the 2-micrometer range.
• Semiconductor Saturable Absorber Mirrors (SESAMs) are widely used for initiating and stabilizing ultrashort pulsed laser operation.

Purpose of the Study:

• To demonstrate and optimize mode-locking in a directly diode-pumped Tm:LuAG laser.
• To investigate the performance of Gallium Antimonide (GaSb)-based SESAMs for this laser system.
• To compare GaSb SESAMs with Gallium Indium Arsenide (GaInAs)-based SESAMs.

Main Methods:

• Direct diode-pumping of a Thulium-doped Lutetium Aluminum Garnet (Tm:LuAG) solid-state laser.
• Employing Gallium Antimonide (GaSb)-based Semiconductor Saturable Absorber Mirrors (SESAMs) for mode-locking.
• Comparative analysis using Gallium Indium Arsenide (GaInAs)-based SESAMs under identical conditions.

Main Results:

• Achieved stable, self-starting mode-locked operation of the Tm:LuAG laser.
• Generated ultrashort pulses with a minimum duration of 13.6 picoseconds (ps) at a wavelength of 2024 nm.
• Obtained a maximum output power of 98 milliwatts (mW).
• Observed longer pulse durations (27 ps and 34 ps) when using GaInAs-based SESAMs.

Conclusions:

• Lattice-matched GaSb-based SESAMs are highly effective for achieving ultrashort pulse generation in 2-micrometer solid-state lasers.
• The study sets a new record for pulse duration in mode-locked Tm:LuAG lasers.
• GaSb SESAMs offer superior performance for mode-locked Tm:LuAG lasers compared to GaInAs SESAMs.