INTERFEROMETRIC MEASUREMENT OF HOLOGRAPHIC LENSLETS

A holographic optical element can either be characterized by the wave aberrations or by the point spread function or alternatively by the mo dulation transfer function. Here we propose the measurement of the wav e aberrations with the help of a Twyman-Green interferometer adapted t o the requirements for testing holographic optical elements. The evalu ation of the interferograms is done with the phase-shifting technique. The resulting wave aberrations are expressed by Zernike coefficients. In addition to this evaluation, the point spread function and the mod ulation transfer function are calculated from the wave aberrations. Th e set-up, the evaluation method and also exemplary results of a tested holographic optical element are presented.