Temperature and angle tuning of second harmonic generation in media with a short-range order

The authors theoretically study the nonlinear optical characterization of the short-range ordered structure and deduce the analytical expression of the effective nonlinear optical coefficient. The dependences of the second harmonic conversion efficiency on crystal temperature, incident angle, and reversed domain cycle are measured. They find that for a substantial range of parameters, the short-range ordered structure has a broader tuning response than the periodic or the quasiperiodic structures. The experimental results accord well with the theory.