The paper “Ultra-broadband near-IR NOPAs based on the nonlinear crystals BiBO and YCOB” by Mario Galletti et al. is featured on the cover of the latest issue of the journal High Power Laser Science and Engineering.

In this work, the GoLP/IPFN researchers from Universidade de Lisboa, in collaboration with colleagues from the Central Laser Facility, STFC, United Kingdom, consider two alternative crystals for both low- and high-energy, few-cycle optical parametric chirped pulse amplification: bismuth borate (BiBO) and yttrium calcium oxyborate (YCOB).

The experimental work was performed at IST Laboratory for Intense Lasers (L2I), where they developed a noncollinear optical parametric amplification (NOPA) setup seeded by a continuum pulse generated from a sapphire plate, operating in the near-infrared region, in order to test each crystal.

For a 5 mm YCOB crystal, they obtained an amplified bandwidth of 200 nm and a gain of ~100, and for a 2.5 mm BiBO crystal they obtained an amplified bandwidth of 240 nm and a gain of ~1000. These results are supported by their theoretical and numerical analysis of the nonlinear process and the “magic” noncollinear angle, which also corroborates the measured spectral profile.

This is the first demonstration of both ultra-broadband OPA in BiBO in the near-IR wavelength range and the broadest bandwidth obtained using YCOB. These results are therefore of high interest to the laser developer community, highlighting promising alternatives to the commonly used nonlinear crystals.

Gonçalo Figueira, head of L2I, states that “these results are remarkable and applicable to many facilities because they clearly show that there is room for improvement in high peak and average power OPCPA by choosing the right combination of nonlinear media and interaction geometry”.

Mario Galletti, a former APPLAuSE student, successfully concluded his PhD in 2020, being awarded to top grade of Pass with Distinction Cum Laude.

To know more:

M. Galletti, H. Pires, V. Hariton, J. Alves, P. Oliveira, M. Galimberti and G. Figueira, Ultra-broadband near-infrared NOPAs based on the nonlinear crystals BiBO and YCOB. High Power Laser Science and Engineering, Vol. 8, Issue 3, 2020.