Polar oxysulfide for nonlinear optical applications
Single crystals of a new noncentrosymmetric polar oxysulfide SrZn 2 S 2 O (s.g. Pmn 2 1 ) grown in a eutectic KF—KCl flux with unusual wurtzite-like slabs consisting of close-packed corrugated double layers of ZnS 3 O tetrahedra vertically separated from each other by Sr atoms and methods of making same.
1. A new zinc oxysulfide compound comprising;
a noncentrosymmetric crystalline structure with chemical formula SrZn 2 S 2 O;
lattice parameters of α=3.87440(10) Å, b=9.9847(3) Å, and c=6.0916(2) Å; and
corrugated double layers of ZnS 3 O tetrahedra vertically separated by Sr 2+ ions.
2. The new zinc oxysulfide compound of claim 1 , wherein an O/S anion ordered arrangement provides two distinct orientations of the ZnS 3 O tetrahedra.
3. The new zinc oxysulfide compound of claim 1 , wherein the compound crystallizes in noncentrosymmetric polar space group Pmn2 1 .
4. The new zinc oxysulfide compound of claim 1 , wherein an O/S anion ordered arrangement yields two distinct orientations of the Zn-centered tetrahedra.
5. The new zinc oxysulfide compound of claim 1 , wherein the compound forms colorless, transparent crystals.
6. The new zinc oxysulfide compound of claim 1 , having a band gap of 3.86 eV.
7. The new zinc oxysulfide compound of claim 1 , wherein the compound is stable up to 650° C. in O 2 gas atmosphere.
8. The new zinc oxysulfide compound of claim 1 , wherein the compound is phase matchable with twice a SHG intensity of potassium dihydrogen phosphate (KDP).
9. The new zinc oxysulfide compound of claim 1 , wherein the compound has a Sr:Zn:S molar ratio of approximately 1.0:2.0:2.3.
10. The new zinc oxysulfide compound of claim 1 , wherein the compound has a band gap energy of 3.86 eV.
11. The new zinc oxysulfide compound of claim 1 , wherein temperatures greater than 1000° C. decompose the SrZn 2 S 2 O compound.