Continuous-wave mode-locked Nd:YAG-pumped subpicosecond dye lasers.

Area of Science:

• Nonlinear Optics
• Laser Physics
• Materials Science

Background:

• Continuous-wave (cw) mode-locked lasers are crucial for generating short optical pulses.
• Potassium titanyl phosphate (KTiOPO4) is a widely used nonlinear optical crystal for frequency doubling.
• Achieving shorter pulse durations requires advanced laser cavity designs and techniques.

Purpose of the Study:

• To investigate the generation of ultrashort optical pulses using a mode-locked Nd:YAG laser.
• To evaluate the performance of KTiOPO4 as a frequency doubler for generating visible light.
• To explore different cavity configurations for optimizing pulse duration and stability.

Main Methods:

• Utilized a cw mode-locked Nd:YAG laser source.
• Employed KTiOPO4 crystals for second-harmonic generation (SHG).
• Implemented synchronously pumped linear and ring cavities with gain and saturable-absorber dye jets.

Main Results:

• Generated 0.532-microm optical pulses with a 39-picosecond (psec) duration and 18% conversion efficiency using KTiOPO4.
• Achieved stable, reproducible optical pulses of 0.24-psec duration in a synchronously pumped linear cavity.
• Obtained optical pulses of 0.15-psec duration in a synchronously pumped ring cavity, though with instabilities.

Conclusions:

• KTiOPO4 is effective for generating visible light pulses from Nd:YAG lasers.
• Synchronously pumped cavities, particularly ring cavities, can produce extremely short optical pulses.
• Further optimization is needed to address instabilities in the shortest pulse duration regimes.