Sub-single-cycle optical pulse train with constant carrier envelope phase.

Area of Science:

• Quantum Optics
• Laser Physics
• Molecular Spectroscopy

Background:

• Generating stable, ultrashort laser pulses is crucial for high-precision measurements and nonlinear optics.
• Controlling the carrier-envelope phase (CEP) of femtosecond pulses is essential for maintaining pulse coherence.
• Molecular modulation offers a promising route for generating multiple, synchronized optical frequencies.

Purpose of the Study:

• To synthesize periodic waveforms composed of ultrashort pulses with controlled carrier-envelope phase (CEP).
• To investigate the stability of CEP in a long train of synthesized pulses.
• To demonstrate the utility of Raman sidebands for generating coherent pulse trains.

Main Methods:

• Synthesis of periodic waveforms using 7 Raman sidebands generated by molecular modulation in hydrogen (H2).
• Generation of pulses with a duration of 0.44 fs and a length of 0.83 cycles.
• Verification of carrier-envelope phase constancy using optical correlation techniques.

Main Results:

• Successfully synthesized periodic waveforms with a train of nearly 10^6 pulses.
• Demonstrated constant carrier-envelope phase across the entire pulse train, with an estimated shift < 0.18 cycles.
• Confirmed CEP stability when synthesizing waveforms from commensurate Raman sidebands.

Conclusions:

• The study successfully demonstrates the synthesis of long pulse trains with stable carrier-envelope phase using molecular modulation.
• This technique provides a robust method for generating coherent ultrashort pulses for advanced optical applications.
• The findings pave the way for improved control over light-matter interactions at the attosecond timescale.