A novel interferometer for measuring the wavefront of multi-wavelength optical pickups

A novel wavefront measurement interferometer is developed that enables the user to evaluate the wavefront of multi-wavelength optical pickups. The interferometer is designed to operate at wavelengths of 405nm, 650nm and 780nm and over the NA range of from 0.6 to 0.85. The instrument is equal path that enables the user to measure pickups with very short coherence length. System accuracy is evaluated and a good agreement with Fujinon V10 interferometer is achieved. Furthermore, the point spread function calculated from the obtained wavefront is compared with the measured spot intensity distribution and the results correlate well with each other.