Abstract

Plane grating (plane hologram) scanners are easy to make and to operate and can produce very straight scan lines in a specific operation condition.¹ This limits their operation to 1-D scanning. For some applications, a 2-D scanning is more convenient and/or desirable. We describe a technique for improving the plane hologram scanner so that straight scan lines can be obtained over wider operating conditions. If the holograms are made with a spherical wave and a plane wave instead of two plane waves, the scan line straightness can be sufficiently improved for 2-D operation. By adjusting the divergence of the spherical wave at the hologram, compensations can be made over considerably large (vertical) deflection angles. This technique can be applied to scanners for which the construction and reconstruction wavelengths may be different. This is advantageous because many hologram recording media are only sensitive at shorter wavelengths but the reconstruction is more economical or convenient at a longer wavelength. Techniques for making the scanners are discussed. Computer simulations and experimental results for the performance of the 2-D scanner are shown.

© 1985 Optical Society of America