Breaking through the “3.0 eV wall” of energy band gap in mid-infrared nonlinear optical rare earth chalcogenides by charge-transfer engineering

Abstract

Increasing the energy band gap under the premise to maintain a large nonlinear optical (NLO) response is a challenging issue for the exploration and molecular design of mid-infrared nonlinear optical...

Symmetry breaking of A3M2X9-type perovskite derivatives induced by polar quaternary ammonium cations: achieving efficient nonlinear optical properties

“…Second-harmonic-generation (SHG) crystal materials are of considerable current interest because of their applications in optoelectronic and laser technologies. [1][2][3][4][5][6][7][8][9][10] Currently, a variety of useful second-order nonlinear optical (NLO) crystals have been developed or commercialized like KBe 2 BO 3 F 2 (KBBF), 11 LiB 3 O 5 (LBO), 12 KH 2 PO 4 (KDP), 13 KTiOPO 4 (KTP), 14 AgGaS 2 (AGS), 15 and ZnGeP 2 (ZGP). 16 Generally, desirable SHG crystals should not only crystallize in noncentrosymmetric (NCS) space groups but also meet the following requirements: (i) high SHG efficiencies, (ii) suitable birefringences (Δn) to achieve phasematching, (iii) wide band gaps, (iv) high laser-induced damage thresholds (LIDTs), (v) superior stability and a low-cost bulk single crystal growth technique.…”

Synthesis, Crystal Structure, and Nonlinear Optical Property of an Anhydrous Sulfate KTb(SO4)2

“…Nonlinear optical (NLO) crystal materials have shown significant interest in modern laser science and technology due to their frequency doubling effect based on the second harmonic generation (SHG). − In recent years, efforts have been made to develop new NLO materials. Therewith, extensive exploration has been made on borates, carbonates, nitrates, and other Π conjugated systems, and thus a series of new NLO materials have been developed, such as KBe 2 BO 3 F 2 , K 7 CaY 2 (B 5 O 10 ) 3 , Na 2 CsBe 6 B 5 O 15 , NaSr 3 Be 3 B 3 O 9 F 4 , Pb 2 BO 3 I, Li 4 Sr­(BO 3 ) 2 , β-Rb 2 Al 2 B 2 O 7 , NaZnCO 3 (OH), ABCO 3 F (A = K, Rb, Cs; B = Ca, Sr), RbMgCO 3 F, YOHCO 3 , Rb 2 Na­(NO 3 ) 3 , RE­(OH) 2 NO 3 (RE = La, Y, and Gd), etc.…”

Noncentrosymmetric Ba6In2Q10 (Q = S, Se): Structural Chemistry and Nonlinear-Optical Activity

“…The available MFIR crystals are far from the market’s requirement, and there is an increasing demand for better ones. Nowadays, the most successful commercial MFIR crystals, AgGaQ 2 (Q = S, Se) , and ZnGeP 2 , encounter several intrinsic defects, restricting their applications; therefore, it is imminent to explore new ones. − …”