A system for a high resolution optical spectrum analyzer (OSA) using an efficient multi-pass configuration is disclosed. The system may include an entrance slit to allow inward passage of an optical beam. The system may also include a grating element to diffract the optical beam. The system may further include a retroreflective element to retroreflect the optical beam. The system may also include a mirror to reflect the optical beam. The system may include an exit slit, which in some examples may be adjacent to the entrance slit. The exit slit may allow outward passage of the optical beam for a high resolution optical measurement.

A system for a high resolution optical spectrum analyzer (OSA) using an efficient multi-pass configuration is disclosed. The system may include an entrance slit to allow inward passage of an optical beam. The system may also include a grating element to diffract the optical beam. The system may further include a retroreflective element to retroreflect the optical beam. The system may also include a mirror to reflect the optical beam. The system may include an exit slit, which in some examples may be adjacent to the entrance slit. The exit slit may allow outward passage of the optical beam for a high resolution optical measurement.

A device for analyzing the material composition of a sample via plasma spectrum analysis includes a laser assembly configured to emit a beam for plasma spectrum analysis and an optical assembly configured to direct the beam towards a target for plasma spectrum analysis of the target. The optical assembly is configured to collect a plasma emitted light emitted from a plasma and provide the plasma emitted light to a dispersion module. The dispersion module includes a first and second diffraction gratings. The first diffraction grating and second diffraction grating are positioned within the dispersion module such that light received from the optical assembly contacts the first diffraction grating at least two times before being directed out of the dispersion module.