Interference fringes arising from multiple reflections can significantly alter the diffraction patterns of diffractive optical elements. One way to reduce interference effects is by time-integrating the diffraction pattern while frequency sweeping the laser source. This method is especially useful when it is not possible to remove the cover glass from the observation camera.
© 1998 Optical Society of America
Markus Duelli, David L. Hill, and Robert W. Cohn, "Frequency Swept Measurements of Coherent Diffraction Patterns," Appl. Opt. 37, 8131-8133 (1998)