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Generation and Coherent Control of Pulsed Quantum Frequency Combs
Published on: June 8, 2018
Ultrafast and octave-spanning optical nonlinearities from strongly phase-mismatched quadratic interactions
1DTU Fotonik, Department of Photonics Engineering, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark.
Physical Review Letters
|September 26, 2012
Summary
Ultrafast cascading nonlinearities are achieved in phase-mismatched crystals, enabling broadband self-defocusing and few-cycle soliton compression. This breakthrough overcomes previous limitations for femtosecond applications.
Area of Science:
- Nonlinear Optics
- Quantum Optics
- Materials Science
Background:
- Cascaded nonlinearities are crucial for frequency conversion but limited by phase-matching and ultrafast response time requirements.
- Existing methods struggle to achieve both high efficiency and femtosecond pulse durations simultaneously.
Purpose of the Study:
- To demonstrate a novel approach for achieving ultrafast cascaded nonlinearities in strongly phase-mismatched crystals.
- To overcome the limitations of traditional phase-matching conditions for femtosecond applications.
Main Methods:
- Utilizing strongly phase-mismatched nonlinear frequency conversion crystals.
- Leveraging the largest quadratic tensor element for enhanced cascaded nonlinearity.
- Experimentally verifying few-cycle soliton compression via noncritical cascaded second-harmonic generation in lithium niobate.
Main Results:
- Observed large, broadband self-defocusing cascaded Kerr-like nonlinearity in phase-mismatched crystals.
- Achieved 47 fs infrared pulse compression to 17 fs (under 4 optical cycles) with 80% efficiency in a 1-mm lithium niobate crystal.
- Generated an octave-spanning supercontinuum upon further pulse propagation.
Conclusions:
- Strongly phase-mismatched cascading provides an ultrafast nonlinear response with octave-spanning bandwidth.
- This method enables efficient few-cycle soliton compression and supercontinuum generation.
- The phenomenon is expected to be applicable across a wide range of near- and mid-infrared pump wavelengths in standard nonlinear crystals.
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