Your question has the answer. Since you say that they can be reduced into Ag particles (I think nano prticles) why do not you measure the size and see. Remeber, you cannot use it for a large range though.

I sorry. My question isn't clear. I mean that there is the Ag seeds in the solution by the UV reduction, then the seeds illuminate different wavelengths of the visible light. Can I get the different morphologies?

It Will depend on the time exscpoure. Different types of laser can give Very different range of morphology