Ultrahigh contrast from a frequency-doubled chirped-pulse-amplification beamline

Area of Science:

• Laser physics
• Nonlinear optics
• High-energy lasers

Background:

• Chirped-pulse amplification (CPA) is a technique for amplifying ultrashort laser pulses.
• Frequency doubling (second-harmonic generation) converts laser light to half its wavelength, often with nonlinear crystals.
• High-energy, short-pulse lasers are crucial for research in fields like inertial confinement fusion and materials science.

Purpose of the Study:

• To describe the frequency-doubled operation of a high-energy CPA beamline.
• To achieve efficient second-harmonic generation (SHG) at high laser energies.
• To characterize the performance of the 527 nm laser pulse output.

Main Methods:

• Utilized a high-energy chirped-pulse amplification (CPA) beamline.
• Employed type-I second-harmonic generation (SHG) with a potassium dihydrogen phosphate (KDP) crystal.
• Conducted experiments across a range of laser energies.

Main Results:

• Achieved efficient type-I second-harmonic generation (SHG) using a 3 mm thick, 320 mm aperture KDP crystal.
• Generated laser pulses exceeding 100 Joules (J) at 527 nm.
• Produced subpicosecond pulses with a high power contrast ratio of 10^14.

Conclusions:

• Demonstrated successful frequency-doubled operation of a high-energy CPA system.
• Validated the use of KDP crystals for efficient SHG in high-power laser systems.
• The achieved pulse parameters (energy, duration, contrast) are suitable for demanding applications.