Effective nonlinearity of the new quaternary chalcogenide crystal BaGa2GeSe6

The unknown magnitude and relative signs of the trigonal crystal B a G a 2 G e S e 6 nonlinear coefficients have hindered defining an optimum orientation for maximum frequency conversion efficiency. This issue is resolved in the present work, obtaining d 11 = + 23.6 , d 22 = − 18.5 , and d 31 = + 18.3 p m / V for frequency doubling of the 10.591 µm radiation.