Hi! Due to symmetry the piezo-optic tensor is represented as a 36 components matrix. Moreover and depending on the crystal structure most of this components are 0 or symmetric. In the case of the alfa-BBO ( 3m structure) this can be represented as (see image), and for the YAG (m3m), see image.
How can I find this symmetries and values for the piezo-optic tensor for structures as beta-BBO (R3c), or in general other laser crystal structures?
References: J.D.Foster. "Thermal Effects in a Nd:YAG Laser"
Y.Vasylkiv "On determination of sign of the piezo-optic coefficients using torsion method"