Chirp-compensated pulsed titanium-sapphire laser system for precision spectroscopy

Area of Science:

• Laser physics
• Quantum optics
• Spectroscopy

Background:

• Pulsed laser systems, such as titanium-sapphire lasers, are essential tools in various scientific fields.
• Accurate frequency control and spectral stability are critical for high-precision measurements and applications.
• Frequency chirp, a time-dependent change in frequency, can limit the performance of pulsed lasers.

Purpose of the Study:

• To demonstrate active frequency-chirp control in a narrowband pulsed titanium-sapphire laser oscillator-amplifier system.
• To improve the spectral resolution and stability of the laser output.
• To quantify the uncertainty contribution due to frequency chirp.

Main Methods:

• Implementation of an intra-cavity electro-optic modulator for active frequency-chirp control.
• Beat-note measurements comparing the pulsed laser output to a continuous-wave laser locked to an optical frequency comb.
• Comparison with the fourth-harmonic upconverted pulsed output to a molecular H2 two-photon resonance for residual chirp correction.

Main Results:

• Successful demonstration of active frequency-chirp control, leading to enhanced spectral resolution and stability.
• Achieved an Allan deviation of 5×10^-11 (at 10 s) in beat-note measurements.
• Determined the uncertainty contribution due to frequency chirp to be below the 1.5×10^-10 level.

Conclusions:

• Active frequency-chirp control is an effective method for improving the performance of pulsed titanium-sapphire lasers.
• The demonstrated technique significantly enhances spectral resolution and stability.
• The achieved low uncertainty contribution from frequency chirp opens possibilities for advanced precision measurements.