Alexandrite laser frequency doubling in beta-BaB(2)O(4) crystals

Area of Science:

• Nonlinear optics
• Solid-state laser technology

Background:

• Efficient generation of coherent ultraviolet (UV) light is crucial for various scientific and technological applications.
• Beta-barium borate (beta-BaB2O4 or BBO) crystals are known for their nonlinear optical properties, enabling frequency conversion.
• Achieving tunable UV output efficiently at room temperature remains a key challenge.

Purpose of the Study:

• To demonstrate efficient and tunable coherent ultraviolet (360-390 nm) generation.
• To investigate the use of type-I phase matching in beta-BaB2O4 crystals for UV generation.
• To characterize the performance of the UV generation system, including phase-matching angles, bandwidths, and energy conversion efficiency.

Main Methods:

• Utilized type-I phase matching in beta-BaB2O4 crystals.
• Employed an alexandrite laser with a tunable wavelength range of 725-785 nm as the pump source.
• Characterized phase-matching angles, angular bandwidth, and spectral bandwidth of the BBO crystal.
• Measured the output UV pulse energy and energy conversion efficiency.

Main Results:

• Achieved efficient and tunable coherent UV generation in the 360-390 nm range.
• Determined the phase-matching angle using the tunable alexandrite laser.
• Measured crystal angular bandwidth of 0.9 mrad-cm and spectral bandwidth of 1.15 nm-cm.
• Obtained a UV output pulse energy of 105 mJ at 378 nm with a 31% energy conversion efficiency.

Conclusions:

• Demonstrated the feasibility of efficient, tunable, room-temperature coherent UV generation using beta-BaB2O4 crystals.
• The results highlight the potential of this method for applications requiring specific UV wavelengths.
• The achieved high energy conversion efficiency and tunable output make BBO crystals a promising material for UV generation.