Laser ablative figuring of optics for phase control

Abstract

In the fabrication procedure of precise optics, the control of the phase distribution of the optics was difficult task because the previous fabrication method was not suitable for the figuring of surface profile. Furthermore, since the previous fabrication was not made on the interferometer, the measurement of the phase distribution was made off-line scheme. We have proposed a novel method for figuring the surface profile of optical plastics and optical glass using very short wavelength excimer laser1). We used ArF laser (λ=193 nm) because the shorter wavelength laser light provides the smoother surface2). We have made some basic experiments on the measurement of the ablation rate of different kinds of optical plastics (PMMA) and optical glass (BK-7) in situ interferometric observation of the surface figure.