The wavefront distortions in a digitally recorded HOE which has the property of a spherical mirror is measured with a Shack-Hartmann wave front sensor to estimate its functional performance. The performance is compared with those in the reconstructed image from Fresnel zone patterns which are displayed on DMDs of different pixel shapes, and with an analog type HOE and a Spherical mirror. The distortion distributions from these samples are not too different from each other. All are revealing spherical mirror properties, though the mirror quality is not the same. This informs that the HOE really work as a spherical mirror. However, the focused beam size of the HOE is much bigger than those of other samples.
The resolution of the reconstructed image from a hologram displayed on a DMD is measured with the light field images along the propagation direction of the reconstructed image. The light field images reveal that a point and line image suffers a strong astigmatism but the line focusing distance differences for lines with different directions. This will be astigmatism too. The focusing distance of the reconstructed image is shorter than that of the object. The two lines in transverse direction are resolved when the gap between them is around 16 pixels of the DMD’s in use. However, the depth direction is difficult to estimate due to the depth of focus of each line. Due to the astigmatism, the reconstructed image of a square appears as a rectangle or a rhombus.
A holographic display which is capable of displaying floating holographic images is introduced. The display is for user interaction with the image on the display. It consists of two parts; multiplexed holographic image generation and a spherical mirror. The time multiplexed image from 2 X 10 DMD frames appeared on PDLC screen is imaged by the spherical mirror and becomes a floating image. This image is combined spatially with two layered TV images appearing behind. Since the floating holographic image has a real spatial position and depth, it allows a user to interact with the image.
A DMD chip is capable of displaying holographic images with a gray level and of reconstructing its image only in the
space defined by the diffraction pattern induced from its pixel arrangement structure. 2 X 5 DMD chips are combined on
a board to generate a spatially multiplexed reconstructed image of 10cmX2cm. Each DMD chip generates an image
piece with the size of 2cm (Horizontal) X 1cm (vertical). The reconstructed image reveals the features of original object
image including the gray level but noises from several sources are also laden with it.
The model of intermediately rough surface as the specific anti-reflection layer is presented for explaining the coloring of
the regular component of a white-light beam forward scattered by a colorless glass with such surface. It is shown that
this model predicts the sequence of colors of the forward scattered component of a white-light beam that is observed in
practice. New experimental arguments supported this approach are provided.