Self-starting 6.5-fs pulses from a Ti:sapphire laser

Area of Science:

• Ultrafast lasers
• Nonlinear optics
• Laser physics

Background:

• Generating ultrashort laser pulses is crucial for various scientific applications.
• Titanium-sapphire lasers are known for their broad gain bandwidth, enabling ultrashort pulse generation.
• Achieving stable, self-starting mode-locking with minimal pulse duration remains a challenge.

Purpose of the Study:

• To demonstrate the generation of self-starting ultrashort pulses from a Kerr-lens mode-locked Ti:sapphire laser.
• To achieve the shortest pulse duration directly from a laser source.
• To investigate methods for effective dispersion compensation and self-starting mode-locking.

Main Methods:

• Utilized a Kerr-lens mode-locked Ti:sapphire laser.
• Employed a prism pair combined with double-chirped mirrors for higher-order dispersion compensation.
• Incorporated a broadband semiconductor saturable-absorber mirror for self-starting mode-locking.

Main Results:

• Successfully generated 6.5-femtosecond (fs) pulses.
• Achieved an average output power of 200 milliwatts (mW).
• Operated at a pulse repetition rate of approximately 86 megahertz (MHz).
• This represents the shortest pulse duration directly generated from a laser to date.

Conclusions:

• The combination of advanced dispersion management and a saturable-absorber mirror enables the generation of unprecedentedly short laser pulses.
• The demonstrated technique paves the way for new possibilities in ultrafast science and technology.
• Self-starting mode-locking was successfully achieved, simplifying laser operation.