AZn₄Ga₅Se₁₂ (A = K, Rb, or Cs): Infrared Nonlinear Optical Materials with Simultaneous Large Second Harmonic Generation Responses and High Laser-Induced Damage Thresholds

Abstract

Despite the fact that nonlinear optical (NLO) crystals such as AgGaS 2 and AgGaSe 2 have been widely used in the infrared (IR) range due to their large second harmonic generation (SHG) coefficients and wide range of IR transparency windows, the small laser-induced damage threshold (LIDT) remains a great issue hindering their high-power applications. Herein, three noncentrosymmetric (NCS) chalcogenides AZn 4 Ga 5 Se 12 (A = K, Rb, or Cs) are successfully obtained through an appropriate flux method after the extensive design and synthesis of the A/Zn/Ga/Q system. Single-crystal X-ray diffraction data demonstrate that they adopt trigonal space group R3 (No. 146) with three-dimensional diamondlike frameworks composed of [M 9 Se 24 ] layers (M = Zn or Ga) stacking in the same direction and filled by charge-balancing A + cations. Noticeably, they all exhibit strong powder SHG responses (2.8−3.7 × AgGaS 2 ) and amazing LIDTs (19.2−23.4 × AgGaS 2 ). In addition, theoretical calculations are performed to further determine the relationship between NCS structures and NLO properties. This work provides effective solutions for overcoming the trade-off between strong SHG and high LIDT in IR-NLO materials.

Infrared nonlinear optical sulfide CsCd4In5S12 exhibiting large second harmonic generation response

“…Similar phenomena are observed in the AX II 4 X III 5 Q 12 family. 56–60 According to the PXRD results, the major components of the decomposition products are CsCd 4 In 5 S 12 and CdIn 2 S 4 .…”

From Cc to P63mc: Structural Variation in La3S2Cl2[SbS3] and La3OSCl2[SbS3] Induced by the Isovalent Anion Substitution

“…Thioantimonates have received considerable attention, because of the existence of lone-pair electrons around Sb 3+ , yielding flexible anionic [SbQ n ] groups, which are responsible for the various crystal structures with fascinating physical properties. − On the other hand, the ratios and charge of counteractions, such as alkali and alkaline-earth metals, play significant roles with regard to the microscopic arrangement of these anionic [SbQ n ] groups. Therefore, modifications can be done by a substitution of the alkali metal, as in the case of Li 3 SbS 3 crystallizing in space group Pna 2 1 and Na 3 SbS 3 adopting space group P 2 1 3. , Moreover, a partial replacement of alkali-metal Ba yielded ABaSbQ 3 that exhibited different space groups, as the result of the different radii of alkali-metal cations .…”

Alkali metal partial substitution-induced improved second-harmonic generation and enhanced laser-induced damage threshold for Ag-based sulfides

“…17 For instance, AgZnPS 4 was obtained using LiZnPS 4 as a parent material via the total Ag substitution of Li, 18 (A 2x Ba 1−x )Ga 2 Se 4 (A = Na and K) was derived from centrosymmetric (CS) BaGaSe 4 through a partial Na and K substitution of Ba, [19][20][21] and K 3 Ga 3 (Ge 7−x M x )Se 20 (M = Si and Sn) was derived from CS K 3 Ga 3 Ge 7 Se 20 by a Si and Sn partial substitution of Ge. 22 General knowledge reveals that the introduction of highly electropositive elements such as alkali or alkaline-earth metals favor the enhancement of the band gaps and LIDTs, [23][24][25] for example, Li 0.6 Ag 0.4 GaS 2 (3.4 eV, 8.6 × AGS), 26 RbZn 4 Ga 6 Se 12 (2.46 eV, 20.5 × AGS), 27 and Ba 6 Zn 7 Ga 2 S 16 (3.5 eV, 28 × AGS). 28 Ideal promising MFIR NLO candidates must meet the double requirements of strong second harmonic generation (SHG) effects and high LIDTs at the same time for high-power laser applications.…”