Provided herein are systems and methods for spatially resolved optical metrology of an ion beam. In some embodiments, a system includes a chamber containing a plasma/ion source operable to deliver an ion beam to a wafer, and an optical collection module operable with the chamber, wherein the optical collection module includes an optical device for measuring a light signal from a volume of the ion beam. The system may further include a detection module operable with the optical collection module, the detection module comprising a detector for receiving the measured light signal and outputting an electric signal corresponding to the measured light signal, thus corresponding to the property of the sampled plasma volume.