# Finding an Orthornomal Polarization?

Say I have a polarization [3i, 2], How do I find a polarization that is orthogonal?

I know that,

$$AA^{\cdot }\; +\; BB^{\cdot }\; =\; 0$$

But my problem is that it yields one equation and two unknowns which I cant solve for. Furthermore, I am a bit confused on the representation of [3i,2] I understand [1,(+/-)i] is circularly polarized light but what about when the i is atop?