Kinoform

Abstract: In an ordinary varifocal or zoom lens system one or more lenses are moved back and forth along the optical axis. But lateral movements can also cause a zoom effect. The refractive or diffractive elements to be moved are no longer rotationally symmetrical. The elements can be made out of transparent material or as a grating with curved lines or as a special version of a kinoform. The zoom systems with lateral motion are very compact.

Abstract: The geometries of objects are deterministic in electromagnetic phenomena in all aspects of our world, ranging from imaging with spherical eyes to stealth aircraft with bizarre shapes. Nevertheless, shaping the physical geometry is often undesired owing to other physical constraints such as aero- and hydro-dynamics in the stealth technology. Here we demonstrate that it is possible to change the traditional law of reflection as well as the electromagnetic characters without altering the physical shape, by utilizing the achromatic phase shift stemming from spin-orbit interaction in ultrathin space-variant and spectrally engineered metasurfaces. The proposal is validated by full-wave simulations and experimental characterization in optical wavelengths ranging from 600 nm to 2800 nm and microwave frequencies in 8-16 GHz, with echo reflectance less than 10% in the whole range. The virtual shaping as well as the revised law of reflection may serve as a versatile tool in many realms, including broadband and conformal camouflage and Kinoform holography, to name just a few.

Abstract: A magneto-optical head using a catadioptric focusing device comprised of an incident surface, a bottom reflective surface, a pedestal, and a body. The incident surface is generally flat and is comprised of a central diffractive, optically transmissive facet and a peripheral facet comprised of a kinoform phase profile. In a data writing or reading mode, an incident optical beam, such as a laser beam impinges upon the central facet, and is diffracted thereby. The incident laser beam can be collimated, convergent or divergent. The laser beam passes through the transparent body, and impinges upon the bottom reflective surface. The laser beam is then reflected by the bottom reflective surface, through the body, unto the kinoform phase profile. The laser beam is reflected and refracted by the peripheral kinoform phase profile as a focused beam, through the body, and is focused as a focal point. The focal point is preferably located at, or in close proximity to a pedestal edge, along a central axis, in very close proximity to the disk. This will allow the focused optical beam to propagate toward, or penetrate the disk through evanescent wave coupling, for enabling the transduction of data to and from the disk.

Abstract: The design of a kinoform by the use of simulated annealing is discussed. The simulated annealing process is applied to decrease the reconstruction noise and to adjust the phase distribution of the kinoform to the configuration of the recording device. A liquid-crystal spatial light modulator is used to display the kinoform. The reconstructed image of the optimized kinoform is found to be in good agreement with the computed image. Some experimental results obtained with a liquid-crystal spatial light modulator are presented. The phase quantization effect of the kinoform is discussed.