Wave-front errors of reference spherical waves in high-numerical aperture point diffraction interferometers

Abstract

Least-squares wave-front reconstruction of Shack-Hartmann sensors and shearing interferometers using multigrid techniques Rev. Sci. Instrum. 76, 053502 (2005); 10.1063/1.1896622 Theoretical analysis of numerical aperture increasing lens microscopy J. Appl. Phys. 97, 053105 (2005); 10.1063/1.1858060 High-power short-pulse laser repetition rate improvement by adaptive wave front correction Rev. Sci. Instrum. 75, 5186 (2004); 10.1063/1.1819379Wave front control systems based on modal liquid crystal lenses Rev. Sci. Instrum. 71, 3290 (2000)

Wavefront error measurement of high-numerical-aperture optics with a Shack-Hartmann sensor and a point source

“…The linear polarization of the beam does not significantly affect the quality of diffractive spherical wavefront. According to Sekine et al 3 the PV WFE of a spherical wavefront after an elliptical pinhole (length of each axis varied from 30 to 60 nm) was within 0.01 ͑ ϭ 13.5 nm͒ even with a linear polarized input beam. As for the 200 nm pinhole, its size was 222 and 216 nm in long and short axes, respectively, which qualifies to generate the spherical wave to test the NA 0.9 optics at 405 nm wavelength.…”

“…Several researchers have demonstrated that the wavefront from a pinhole is a near-ideal spherical wave. [3][4][5] However, the conventional PDI or phaseshifting point-diffraction interferometer 6 (PS͞PDI) has been used for low NA optics because of feature size limitation in the point-diffraction device, even though some researchers developed a special PDI to measure the NA 0.8 optics. 7 In the research described below, we developed a new, to the best of our knowledge, method to measure the transmitted WFE of the high-NA optics by using a Shack-Hartmann (SH) sensor as a wavefront sens-ing instrument and a pinhole to generate the reference spherical wave.…”