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Direct Imaging of Laser-driven Ultrafast Molecular Rotation
Published on: February 4, 2017
Characterizing isolated attosecond pulses from hollow-core waveguides using multi-cycle driving pulses
1JILA, University of Colorado and NIST, Boulder, Colorado 80309, USA. Isabell.Thomann@Colorado.edu
Optics Express
|March 19, 2009
Summary
Researchers generated isolated attosecond extreme-ultraviolet pulses using longer, carrier-envelope-phase (CEP) unstabilized near-infrared laser pulses. This breakthrough in attosecond pulse generation utilized novel phase matching in a hollow-core waveguide.
Area of Science:
- Quantum optics
- Attosecond science
- Nonlinear optics
Background:
- High-order harmonic generation (HHG) is a key process for generating ultrashort light pulses.
- Previous methods for isolated attosecond pulse generation often required shorter driving laser pulses.
- Carrier-envelope-phase (CEP) stabilization is typically crucial for precise control in attosecond science.
Purpose of the Study:
- To demonstrate the generation of isolated attosecond extreme-ultraviolet (EUV) pulses from longer duration, CEP unstabilized near-infrared (NIR) driving pulses.
- To investigate the role of dynamically changing phase matching conditions in a hollow-core waveguide for attosecond pulse generation.
- To adapt and apply FROG CRAB analysis for characterizing attosecond pulses generated under non-ideal (CEP unstabilized) driving conditions.
Main Methods:
- Experimental generation of EUV pulses using HHG driven by 15 fs NIR pulses in a hollow-core waveguide filled with Argon.
- Cross-correlation measurements using the laser-assisted photoelectric effect to probe the EUV pulse duration.
- FROG CRAB (Frequency Resolved Optical Gating and Cross-correlation Autocorrelation) analysis using a generalized projections (GP) algorithm and direct simulations.
- Adaptation of GP algorithm for wide-angle photoelectron detection and non-CEP stabilized driving pulses.
Main Results:
- Successfully generated isolated attosecond EUV pulses with a duration of approximately 200 attoseconds.
- Demonstrated that CEP unstabilized, 15 fs multi-cycle NIR pulses can drive the generation of isolated attosecond pulses.
- Showcased the effectiveness of dynamically changing phase matching in a hollow-core waveguide for this process.
- Validated FROG CRAB analysis, including direct simulations, for characterizing pulses under these conditions.
Conclusions:
- Isolated attosecond EUV pulse generation is achievable with significantly longer and CEP unstabilized driving pulses than previously thought.
- Hollow-core waveguides offer a viable geometry for controlling phase matching to enable isolated attosecond pulse generation.
- The developed FROG CRAB analysis methods are robust for characterizing ultrashort pulses generated under challenging experimental conditions.
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