Deep Ultraviolet Nonlinear Optical Materials

Abstract

Deep ultraviolet (absorption edge <200 nm, band gap >6.2 eV) nonlinear optical (NLO) materials are of current interest owing to their technological applications and materials design challenges. Technologically, the materials are used in laser systems, atto-second pulse generation, semiconductor manufacturing, and photolithography. Designing and synthesizing a deep UV NLO material requires crystallographic noncentrosymmetry, a wide UV transparency range, a large second-harmonic generating coefficient (d ij > 0.39 pm/V), moderate birefringence (Δn ∼ 0.07), chemical stability and resistance to laser damage, and ease in the growth of large high-quality single crystals. This review examines the known deep UV NLO materials with respect to their crystal structure, band gap, SHG efficiency, laser damage threshold, and birefringence. Finally, future directions with respect to new deep UV NLO materials are discussed.

K3B6O9F3: A New Fluorooxoborate with Four Different Anionic Units

“…It is well known that borates possess diverse structures . In typical polyborate structures, there are two kinds of units, [BO 3 ] 3− triangles and [BO 4 ] 5− tetrahedra, which are hybridized by planar sp 2 and three dimensional sp 3 , respectively.…”

On the Anionic Group Approximation to the Borate Nonlinear Optical Materials

“…With the above tabulated second-order NLO susceptibilities for the simple ideal anionic groups (Table 1), it should not be difficult to apply them to the recently found or proposed NLO borate or carbonate crystals [32]. For example, recently we succeeded in growing a new NLO crystal with a chemical formula of K 3 B 6 O 10 Br (Figure 1) [33] into a sufficient size, which was first reported by Al-Ama et al [34], and it contains a borate network skeleton with an exceptionally large anionic group, B 6 O 13 , composed of three BO 3 and three BO 4 groups (Figure 2).…”

Comparative Interrelationship of the Structural, Nonlinear-Optical and Other Acentric Properties for Oxide, Borate and Carbonate Crystals

“…Besides moderate nonlinear optical (NLO) susceptibility χ (2) , acentric borate crystals are widely used in optoelectronics for the efficient optical frequency conversion in the visible and ultraviolet (UV) spectral ranges, and the creation of self-frequency-doubling lasers because of their high transparency and high optical damage threshold [4][5][6][14][15][16][17][18][19]56,66,67,. More 220 simple and binary acentric borate crystals, including new complex borate-carbonate, borate-nitrate, borate-acetate, hydroxyl-borate, borate-sulfate, borate-phosphate, borate-silicate, borate-fluoride, and other compounds with several different cations or anions [14][15][16][17]56, are currently known.…”