Inorganic Solid-State Nonlinear Optical Switch with a Linearly Tunable Tc Spanning a Wide Temperature Range

Nonlinear optical (NLO) switch materials that turn on/off second-harmonic generation (SHG) at a phase transition temperature (Tc) are promising for applications in the fields of photoswitching and optical computing. However, precise control of Tc remains challenging, mainly because a linearly tunable Tc has not been reported to date. Herein, we report a unique selenate, tetragonal P.421c [Ag(NH3)2]2SeO4 with a= b= 8.5569(2) A and c= 6.5208(2) A that exhibits a strong SHG intensity (1.3xKDP) and a large birefringence (.nobv.= 0.08). This compound forms a series of isostructural solid-solution crystals [Ag(NH3)2]2SxSe1 xO(4) (x= 01.00) that exhibit excellent NLO switching performance and an unprecedented linearly tunable Toc; xTHORN; oexp:THORN 1/4 T0 kx spanning 430 to 356 K. The breaking of localized hydrogen bonds between SeO42 and the cation triggers a phase transition accompanied by hydrogen bond length changes with increasing x and a linear change in the enthalpy DHx 1/4 oDU1 DU2THORNx thorn DU2.

Automated summary

A material with nonlinear optical switch properties that can switch second-harmonic generation at a phase transition temperature has been reported, showing potential for applications in photoswitching and optical computing. The study achieved precise control of the phase transition temperature by forming a series of solid-solution crystals, which exhibited excellent nonlinear optical switching performance and a linear tunable temperature range.