Hologram measurements are becoming more and more popular as a reliable method for identifying bad elements and the tuning of active phased array antennas. Relying on holographic data to adjust phase shifters and attenuators in these antennas can give undesired results if the accuracy of the data is poor. Often measurements can be improved if the error sources can be isolated and quantified. Thi...

An efficient method for obtaining modified Fresnel holograms of real existing three-dimensional (3-D) scenes illuminated by incoherent white light is presented. To calculate the hologram, the method uses multiple-viewpoint projections of the 3-D scene. However, contrary to other similar methods, this one is able to calculate the Fresnel hologram of the 3-D scene directly rather than calculating...

We present an improved method for recording a synthesized Fourier hologram under incoherent white-light illumination. The advantage of the method is that the number of real projections needed for generating the hologram is significantly reduced. The new method, designated as synthetic projection holography, is demonstrated experimentally. We show that the synthetic projection holography barely ...

An optoelectronic technique for 3D object recognition using single off-axis digital Fresnel hologram is demonstrated. Only one Fresnel digital hologram of the 3D object to be recognized is recorded. The electronic hologram is processed digitally to retrieve 3D object information encoded as a 2D digital image. Wavelet matched filtering is used to improve the discrimination capability of the corr...

We propose a large-scale hologram calculation using WAvelet ShrinkAgeBased superpositIon (WASABI), a wavelet transform-based algorithm. An image-type hologram calculated using the WASABI method is printed on a glass substrate with the resolution of 65, 536×65, 536 pixels and a pixel pitch of 1μm. The hologram calculation time amounts to approximately 354 s on a commercial CPU, which is approxim...

An information security method that uses a digital holographic technique is presented. An encrypted image is stored as a digital hologram. The decryption key is also stored as a digital hologram. The encrypted image can be electrically decrypted by use of the digital hologram of the key. This security technique provides secure storage and data transmission. Experimental results are presented to...

A technique to determine a real nonnegative function representing the transmittance of a synthesized hologram is described. The technique uses the positions of the samples in the synthesized hologram to record the phase information of a complex wavefront. Synthesized holograms are displayed on a flying spot scanner and recorded on film. The transmittance of the synthesized hologram is quantized...

Metasurfaces are engineered interfaces that contain a thin layer of plasmonic or dielectric nanostructures capable of manipulating light in a desirable manner. Advances in metasurfaces have led to various practical applications ranging from lensing to holography. Metasurface holograms that can be switched by the polarization state of incident light have been demonstrated for achieving polarizat...