Intense Two-Octave Ultraviolet-Visible-Infrared Supercontinuum Laser via High-Efficiency One-Octave Second-Harmonic...

Area of Science:

• Nonlinear Optics
• Laser Physics
• Materials Science

Background:

• Intense ultrabroadband laser sources are crucial for diverse scientific applications.
• Existing laser technologies face limitations in bandwidth and pulse energy.

Purpose of the Study:

• To design and realize a novel nonlinear crystal for ultrabroadband laser generation.
• To achieve high conversion efficiency and broad spectral coverage in second-harmonic generation and supercontinuum generation.

Main Methods:

• Utilized chirped periodically poled lithium niobate (PPLN) nonlinear crystal.
• Implemented up to 12 orders of quasiphase matching (QPM).
• Employed a Ti:sapphire femtosecond laser as the pump source.

Main Results:

• Achieved ultrabroadband second-harmonic generation (SHG) from 700-1700 nm to 350-850 nm with ~25.8% average conversion efficiency.
• Generated a flat supercontinuum spectrum with >1 octave (375-1200 nm) and >2 octaves (350-1500 nm) bandwidth.
• Obtained high pulse energy of 0.17 mJ/pulse from 0.48 mJ/pulse pump via synergistic nonlinearities.

Conclusions:

• The developed chirped PPLN crystal enables efficient ultrabroadband laser generation.
• This method offers a promising route for constructing supercontinuum laser sources with broad bandwidth and high pulse energy.
• The laser source has potential applications in basic science and high technology.