Comparison and characterization of efficient frequency doubling at 397.5 nm with PPKTP, LBO and BiBO crystals

TL;DR

This paper compares the efficiency, beam quality, and stability of frequency doubling at 397.5 nm using PPKTP, LBO, and BiBO crystals with a 795 nm Ti:sapphire laser, highlighting the optimal crystal for UV generation.

Contribution

It provides a direct experimental comparison of three nonlinear crystals for efficient UV generation at 397.5 nm using a continuous-wave Ti:sapphire laser.

Findings

PPKTP achieved the highest doubling efficiency of 58.1%.

LBO produced 770 mW UV output with 57.4% efficiency.

BiBO had a lower efficiency of 35.9%.

Abstract

A continuous-wave Ti:sapphire laser at 795 nm is frequency doubled in a bow-tie type enhancement four-mirror ring cavity with LiB3O5 (LBO), BiB3O6 (BiBO), and periodically polled KTiOPO4 (PPKTP) crystals, respectively. The properties of 397.5 nm ultra-violet (UV) output power, beam quality, stability for these different nonlinear crystals are investigated and compared. For PPKTP crystal, the highest doubling efficiency of 58.1% is achieved from 191 mW of 795 nm mode-matched fundamental power to 111 mW of 397.5 nm UV output. For LBO crystal, with 1.34 W of mode-matched 795 nm power, 770 mW of 397.5 nm UV output is achieved, implying a doubling efficiency of 57.4%. For BiBO crystal, with 323 mW of mode-matched 795 nm power, 116 mW of 397.5 nm UV output is achieved, leading to a doubling efficiency of 35.9%. The generated UV radiation has potential applications in the fields of quantum physics