[HFSS] Using optimetrics to maximize |E| at a certain position in metamaterial design

Hello all,

I've been simulating 'perfect lens' by creating arrays of metamaterial. So far, HFSS has been very satisfying.

I am at a point where I need to find the frequency which gives the maximum |E| at a certain focusing point in the structure.
In other words, how do I create a probe to detect |E| at a specified position and use optimetrics to calculate the frequency where |E| is maximized?

Please tell me if my question is not clear. I'm happy to explain more.

Your help is very VERY appreciated!