Low repetition rate SESAM modelocked VECSEL using an extendable active multipass-cavity approach

Area of Science:

• Optics and Photonics
• Semiconductor Lasers
• Ultrafast Lasers

Background:

• Vertical External Cavity Surface Emitting Lasers (VECSELs) offer wavelength flexibility over diode-pumped solid-state lasers.
• Reducing pulse repetition rate typically increases pulse energy and peak power in pulsed lasers.
• Semiconductor gain materials in VECSELs have short carrier lifetimes, limiting low repetition rate operation and causing multiple pulse buildup.

Purpose of the Study:

• To overcome the limitations of short carrier lifetimes in VECSEL gain materials.
• To achieve fundamental modelocking at low repetition rates for increased pulse energy and peak power.
• To demonstrate an active multipass approach for enhanced VECSEL performance.

Main Methods:

• Application of an active multipass technique to VECSELs.
• Passively modelocking VECSELs.
• Characterization of pulse parameters including repetition rate, average output power, and pulse duration.

Main Results:

• Fundamental modelocking achieved at a repetition rate of 253 MHz.
• Average output power of 400 mW obtained.
• Pulses with a duration of 11.3 ps were generated.

Conclusions:

• The active multipass approach effectively enables fundamental modelocking in VECSELs at low repetition rates.
• This technique overcomes the challenge of short carrier lifetimes in semiconductor gain materials.
• The demonstrated VECSEL performance offers a promising compact pulsed laser source with high pulse energy.