An apparatus for cross-flow purging for optical components in a chamber, including: a housing with first and second axial ends, a side wall extending in an axial direction and connecting the first and second axial ends, and the chamber formed by the first and second axial ends and the side wall; an optical component disposed within the chamber and fixed with respect to the housing via at least one connecting point on the optical component; an inlet port aligned with the side wall, between the first and second axial ends in the axial direction, in a radial direction orthogonal to the axial direction and arranged to inject a purge gas into the chamber and across the optical component in a radial direction orthogonal to the axial direction; and an exhaust port aligned with the side wall in the radial direction and arranged to exhaust the purge gas from the chamber.