A solution for irradiating a surface with ultraviolet radiation is provided. A movable optical element is utilized to form a beam of ultraviolet radiation having a characteristic cross-sectional area smaller than an area of the surface to be irradiated. The movable optical element can be moved as necessary to directly irradiate any portion of the surface with radiation within the characteristic cross-sectional area of the beam of ultraviolet radiation. The movement can include, for example, rotational movement and/or repositioning the movable ultraviolet source with respect to the surface.