A device for analyzing the material composition of an object via plasma spectrum analysis includes an optical assembly having a first aspheric mirror and a second aspheric mirror. The first and second aspheric mirrors have an aspheric surface profile. The first aspheric mirror is configured to receive a laser beam at non-normal incidence along a first axis. The optical assembly is configured such that the first aspheric mirror directs the beam to the object for plasma spectrum analysis along a second axis, the second axis being different from the first axis. The plasma emitted light emitted is collected coaxially along the second axis and redirected along the first axis in the opposite direction by the first aspheric mirror. The second aspheric mirror is configured to redirect a portion of the plasma emitted light along a third axis to a spectrometer for analysis.