What are the geometric characteristics of a cylindrical concave metallic mirror?
Concave surfaces are cylindrical (radius of curvature R) and have focusing or divergence capability in only one dimension (e.g., X direction).
Plano surfaces have no optical focus and keep light rays from being deflected in the vertical direction (e.g., Y direction).
Focal length calculation (cylindrical direction): F=R/2
(negative values indicate concave surfaces for beam convergence or divergence)

What are the optical functions of a cylindrical concave metallic mirror?
Incident light type	Cylindrical concave mirrors function
Parallel light	Focuses into a linear spot in the column plano direction (Y direction remains parallel).
Divergent light	Correcting divergence in the column direction (e.g., laser diode fast-axis compression).
Focused light	Adjustment of spot shape in the direction of the column (e.g. round spot becomes elliptical).