Picosecond passively mode-locked GaSb-based semiconductor disk laser operating at 2 μm

Area of Science:

• Semiconductor laser technology
• Optoelectronics
• Quantum well physics

Background:

• Semiconductor disk lasers (SDLs) are crucial for generating high-power laser output.
• Optically pumped SDLs offer advantages in scalability and wavelength flexibility.
• Achieving stable mode-locking in the mid-infrared spectrum remains a challenge.

Purpose of the Study:

• To demonstrate a passively mode-locked, optically pumped GaSb-based semiconductor disk laser.
• To achieve stable picosecond pulse generation at a 1.95 μm wavelength.
• To investigate the performance of InGaSb/GaSb quantum wells for laser gain and mode-locking.

Main Methods:

• Utilized a 15 quantum well InGaSb/GaSb structure as the gain mirror.
• Employed a semiconductor saturable absorber mirror (SESAM) with three InGaSb/GaSb quantum wells.
• Achieved self-starting mode-locked operation via optical pumping.
• Characterized pulse duration, energy, and repetition rate.

Main Results:

• Stable picosecond optical pulses were generated at 1.95 μm.
• Self-starting mode-locked operation was achieved at a fundamental repetition rate of 881.2 MHz.
• Pulses with 30 pJ energy and 1.1 ps duration were produced.
• Pulse characteristics were within a factor of 2 of the Fourier limit.

Conclusions:

• The developed GaSb-based semiconductor disk laser is effective for generating high-quality picosecond pulses.
• The InGaSb/GaSb quantum well design is suitable for both gain and saturable absorption in mode-locked lasers.
• This work contributes to advancements in mid-infrared laser sources for various applications.