Record fifth-harmonic-generation efficiency producing 211  nm, joule-level pulses using cesium lithium borate.

Area of Science:

• Nonlinear Optics
• Laser Technology
• Quantum Electronics

Background:

• Efficient generation of higher harmonics from pulsed lasers is crucial for various scientific applications, including spectroscopy and materials processing.
• Previous methods for generating the fifth harmonic of Nd:YLF lasers faced limitations in efficiency and output energy.

Purpose of the Study:

• To achieve a record-high conversion efficiency for the fifth harmonic of a pulsed Nd:YLF laser.
• To demonstrate the generation of deep ultraviolet pulses at 211 nm with high energy.

Main Methods:

• Utilized a cascade of nonlinear crystals for harmonic generation.
• Employed cesium lithium borate (CsB3O5) in a Type-I configuration for sum-frequency mixing of 1053 nm and 266 nm fundamental wavelengths.
• Optimized beam profiles and pulse shapes to maximize conversion efficiency.

Main Results:

• Achieved a record conversion efficiency of 30% for the fifth harmonic generation.
• Successfully generated 211 nm pulses with energies up to 335 mJ.
• Demonstrated stable 2.4 ns pulse durations at the fifth harmonic.

Conclusions:

• The developed method provides a highly efficient route for generating the fifth harmonic of Nd:YLF lasers.
• The high-energy, deep ultraviolet pulses are suitable for advanced scientific and technological applications.
• Optimization of beam and pulse characteristics is key to maximizing nonlinear optical conversion efficiencies.