For obtaining matlab code of lens

Dear Sir,

My name is Mohamed Elwakdy. I am working as Research Assistant at American University in Cairo. I am working in radar project at American University from August 1, 2011. In this project, I am using Matlab Program and I have difficult to solve some problems with this program. In this project, I will send the chirp signal as embedded signal in the laser beam to the object through lens. I would like to know “What is the Matlab code that I must use it to describe the lens??”

Thank you very much

Have Great and Fantastic Day

Mohamed