Fabrication of large-sag aspheric micro-optics with nanometer accuracy using electron-beam lithography on curved substrates

Abstract

Smooth patterns were written into PMGI electron-beam resist using electron-beam lithography on BK7 blank concave mirror substrates, resulting in aspheric optics with sag as large as 4 m. Interference microscope measurements revealed that the fabricated optics had height accuracy of 10 nm. These optics were designed for flattop mode shaping in laser resonators. Excellent performance of these optics has been demonstrated by testing them as fixed phase-conjugate mirrors outside laser resonators, as well as mode-shaping mirrors within laser resonators.