| 摘要 |
A projection objective of a microlithographic projection exposure apparatus comprises a wavefront correction device comprising a refractive optical element that has two opposite optical surfaces, through which projection light passes, and a circumferential rim surface extending between the two optical surfaces. A first and a second optical system are configured to direct first and second heating light to different portions of the rim surface such that at least a portion of the first and second heating light enters the refractive optical element. A temperature distribution caused by a partial absorption of the heating light results in a refractive index distribution inside the refractive optical element that corrects a wavefront error. At least the first optical system comprises a focusing optical element that focuses the first heating light in a focal area such that the first heating light emerging from the focal area impinges on the rim surface. |
