Pulse colliding in a self-mode-locked ring-cavity ti:sapphire laser

Area of Science:

• Laser physics
• Ultrafast optics

Background:

• Ti:sapphire lasers are crucial for generating ultrashort pulses.
• Mode-locking techniques enable femtosecond pulse generation.
• Ring-cavity configurations offer unique operational characteristics.

Purpose of the Study:

• To introduce a new self-mode-locked ring-cavity Ti:sapphire laser.
• To investigate its performance in both unidirectional and bidirectional operations.
• To analyze the underlying physical mechanisms responsible for observed phenomena.

Main Methods:

• Development of a self-mode-locked ring-cavity Ti:sapphire laser.
• Experimental comparison of unidirectional and bidirectional mode-locking.
• Analysis of spectral and temporal pulse characteristics.

Main Results:

• The laser achieves self-mode-locking in both unidirectional and bidirectional regimes.
• Bidirectional operation leads to clockwise and counterclockwise pulse collision within the Ti:sapphire rod.
• Spectrum narrowing and pulse broadening are observed in bidirectional mode-locking compared to unidirectional operation.

Conclusions:

• The observed spectral narrowing and pulse broadening in bidirectional mode-locking are attributed to a transient grating effect.
• This transient grating within the gain medium limits the oscillation spectrum.
• The findings provide insights into the complex dynamics of bidirectional mode-locked lasers.