Co-crystal LiCl·(H 3 C 3 N 3 O 3 ): a promising solar-blind nonlinear optical crystal with giant nonlinearity from coplanar π-conjugated groups

Compact and reliable all-solid-state solar-blind lasers based on nonlinear optical conversion are opening the door to new industrial applications of lasers. Herein, we proposed the cyanuric acid molecule, benefiting from its wide band gap, considerable optical anisotropy, and strong binding interaction resulting from hydrogen bonds, to be a superior building block for solar-blind NLO crystals. Taking the co-crystal LiCl·(H3C3N3O3) as an example, our first-principles studies predicted this crystal to display a short UV transparent edge of 215 nm, strong optical anisotropy (Δn ∼ 0.28), and a second-order coefficient (d22 = 4.15 pm V-1) greater than those of all other investigated solar-blind NLO crystals.