Hi Stephen,
Thanks for replying!
I think I should have said that the \phi_T angle is always about the X axis that is defined on the mirror. So therefore it is the same angle; it is only defined as \phi_T to give it similar nomenclature to \phi_Z.
I'm having trouble, though, seeing what...
I am starting to deal with optomechanical systems as part of my work, and am faced with what seems to be an uncomplicated problem, however I'm ashamed to admit that I am having great difficulty getting to grips with it. I'd like some pointers and/or advice as to how to go about solving these...