Dynamic gain aperture modelocking in picosecond regime based on cascaded second-order nonlinearity

Area of Science:

• Laser Physics
• Nonlinear Optics
• Materials Science

Background:

• Mode-locked lasers are crucial for generating ultrashort optical pulses.
• Neodymium-doped yttrium orthovanadate (Nd:YVO4) lasers offer specific advantages for pulsed operation.
• Kerr lens mode-locking is a common technique for achieving short pulse durations.

Purpose of the Study:

• To investigate the operational characteristics of a cascaded second-order mode-locked Nd:YVO4 laser.
• To model the laser system considering soft-aperture Kerr lens effects and complex beam parameters.
• To analyze the influence of cascaded Kerr nonlinearity on gain aperturing.

Main Methods:

• Utilizing complex beam parameters for laser analysis.
• Employing a self-consistent complex beam propagation method.
• Incorporating radially varying gain aperturing effects.

Main Results:

• The theoretical analysis predicted a stable pulsewidth of approximately 9.5 picoseconds.
• The calculated pulsewidth shows excellent agreement with the experimentally measured value of 10.3 picoseconds.
• The study successfully modeled the interplay between Kerr nonlinearity and gain aperturing.

Conclusions:

• The complex beam parameter approach provides an accurate method for analyzing mode-locked lasers with Kerr nonlinearity.
• The investigated Nd:YVO4 laser system demonstrates stable and predictable ultrashort pulse generation.
• This research contributes to the understanding and design of advanced pulsed laser systems.