Large Second Harmonic Generation (SHG) Effect and High Laser‐Induced Damage Threshold (LIDT) Observed Coexisting in Gallium Selenide

Abstract

A big challenge for nonlinear optical (NLO) materials is the application in high power lasers, which needs the simultaneous occurrence of large second harmonic generation (SHG) and high laser induced damage threshold (LIDT). Herein we report the preparation of a new Ga2Se3 phase, which shows the SHG intensities of around 2.3 times and the LIDT of around 16.7 times those of AgGaS2 (AGS), respectively. In addition, its IR transparent window ca. 0.59–25 μm is also significantly wider than that of AGS (ca. 0.48–≈11.4 μm). The occurrence of the strong SHG responses and good phase‐matching indicate that the structure of the new Ga2Se3 phase can only be non‐centrosymmetric and have a lower symmetry than the cubic γ‐phase. The observed excellent SHG and phase‐matching properties are consistent with our diffraction experiments and can be well explained by using the orthorhombic models obtained through our high throughput simulations.

[GaF(H2O)][IO3F]: a promising NLO material obtained by anisotropic polycation substitution

“…S5 †). The solidstate 19 F nuclear magnetic resonance (NMR) spectrum displays two peaks with characteristic F chemical shi values of À90.37 and À101.42 ppm, coinciding with the previously reported value, 41 and that these correspond to two different F environments that can exist (Fig. S6 †).…”

“…S6 †). The relatively wide 19 F chemical shi range should ascribe to the stable structure of [GaF(H 2 O)] [IO 3 F] and the low mobility of F À anions. Elemental analysis (EA) result shows that the percentage of H in the original sample is 0.65%, corresponding to two H atoms of the molecular formula.…”

“…[11][12][13] However, currently commercialized mid-IR NLO crystals, such as AgGaS 2 (AGS), AgGaSe 2 and ZnGeP 2 , [14][15][16] have been heavily restricted by their relatively smaller band gaps which can always result in harmful two-photon absorptions and lower laser-induced damage thresholds (LDTs). 6,[17][18][19][20] Consequently, it is still urgent to explore mid-IR NLO material with improved band gap (or LDT) and great comprehensive properties.…”

From Ag2Zr(IO3)6 to LaZr(IO3)5F2: A Case of Constructing Wide‐band‐gap Birefringent Materials through Chemical Cosubstitution

“…[1][2][3] Among the many NLO systems that have been well-investigated such as borates and borate-analogs (nitrate, carbonate, and cyanurate), chalcogenides, selenites (tellurites) and iodates, etc, the iodate-based system is considered to be a promising category of crystalline materials showing excellent second harmonic generation (SHG) response, exemplified by the commercialized α-LiIO 3 (300 × α-SiO 2 ). [4][5][6][7][8][9][10][11] The stereochemically active lone pairs on I 5 + , known as a highly second-order Jahn-Teller (SOJT) distortive chromophore, favor the formation of noncentrosymmetric structure and large SHG responses. [6][7] So far, the introduction of other SOJT distortive cations (V 5 + , Nb 5 + , Bi 3 + , Pb 2 + , etc.)…”

“…The standing call for high‐performance laser sources as a result of the rapid development and wide application of optic and laser technology has been continuously drawing academic interest and led to many meaningful advances in the field of nonlinear optical (NLO) crystals over the past decades [1–3] . Among the many NLO systems that have been well‐investigated such as borates and borate‐analogs (nitrate, carbonate, and cyanurate), chalcogenides, selenites (tellurites) and iodates, etc , the iodate‐based system is considered to be a promising category of crystalline materials showing excellent second harmonic generation (SHG) response, exemplified by the commercialized α ‐LiIO 3 (300× α ‐SiO 2 ) [4–11] . The stereochemically active lone pairs on I 5+ , known as a highly second‐order Jahn‐Teller (SOJT) distortive chromophore, favor the formation of noncentrosymmetric structure and large SHG responses [6–7] .…”