Ultrashort CO(2) laser pulse generation by square-wave mode locking and cavity dumping

Area of Science:

• Laser Physics
• Optoelectronics
• Quantum Electronics

Background:

• Carbon dioxide (CO2) lasers are crucial for various scientific and industrial applications.
• Achieving ultrashort pulse durations in CO2 lasers is a persistent challenge.
• Existing mode-locking techniques have limitations in pulse width and stability for CO2 systems.

Purpose of the Study:

• To report the first successful implementation of active square-wave mode locking and cavity dumping in a CO2 laser system.
• To achieve generation of high-energy, ultrashort single pulses from a CO2 laser oscillator.
• To investigate the synchronizability and stability of the generated pulses.

Main Methods:

• Utilized active square-wave mode locking and cavity dumping techniques.
• Employed a 10-atm transversely excited (TE) discharge CO2 laser amplifier module.
• Seeded the laser cavity with radiation from a line-tunable continuous-wave (cw) CO2 laser.
• Integrated injection locking and Q-switching for enhanced pulse control.

Main Results:

• Reliably produced single pulses with 5-mJ energy and durations less than 500 picoseconds (detection limited).
• Achieved a timing jitter of less than +/-50 picoseconds relative to the UV-triggered spark gap firing.
• Demonstrated the shortest pulse durations reported for actively mode-locked CO2 lasers.

Conclusions:

• Active square-wave mode locking and cavity dumping are effective for generating ultrashort pulses in CO2 lasers.
• The developed system offers high energy, precise timing, and unprecedented short pulse widths.
• This breakthrough has significant implications for applications requiring high-power, ultrafast CO2 laser pulses.