Microlithographic projection exposure apparatus (100) has a projection lens (150) configured to image an object plane (155) onto an image plane (156), wherein an immersion liquid is at least temporarily provided during operation of the projection exposure apparatus between the projection lens and the image plane, wherein a measurement structure (121) is arranged in the immersion liquid, and wherein the measurement structure is configured to generate a measurement pattern. The projection exposure apparatus also has a measurement device (130, 160) configured to measure the measurement pattern. The measurement structure has an absorption layer (125) including silicon oxide and/or silicon oxynitride and/or nitride.