A novel method for computer-generated rainbow holograms (CGRHs) of full-color objects is proposed. First, a new algorithm for fabricating full-color CGRHs of real-existing objects is proposed based on the interrelationship between coding of a CGRH and reconstruction of the hologram. Second, a color rainbow hologram for a real-existing object is generated by combining the proposed algorithm and computer-generated hologram generating system. Finally, the hologram is outputted by an auto-microfilming system. The principle of the algorithm, the process of hologram calculation, and the hologram generating system for real-existing objects and experimental results are presented. The experimental results demonstrate that the new method is feasible.

We introduce another type of Pearcey beam, namely, dual Pearcey (DP) beams, based on the Pearcey function of catastrophe theory. DP beams are experimentally generated by applying Fresnel diffraction of bright elliptic rings. Form-invariant Bessel distribution beams can be regarded as a special case of DP beams. Subsequently, the basic propagation characteristics of DP beams are identified. DP beams are the result of the interference of two half DP beams instead of two classical Pearcey beams. Moreover, we also verified that half DP beams (including special-case parabolic-like beams) generated by half elliptical rings (circular rings) are a new member of the family of form-invariant beams.

The ability to noninvasive image through turbid media has long been a major scientific and technological goal in many disciplines. A breakthrough has been made to observe objects that were completely hidden behind an opaque scattering layer. However, such approach needs not only to scan both illumination light and detector but further off-line procedures to numerically retrieve the image of the objects. Here, we report a distant invisibility-based noninvasive method that can hide scattering layers and allows to directly image objects behind. By recording holograms of the objects through a ground glass and then using the holograms produced time-reversal lights to re-illuminate the objects, we implemented to observe objects with feature size ranging from 39 μm to 80 μm that were hidden behind a 3 mm thick ground glass. Of importance, our approach opens a door towards real-time, high speed biomedical imaging and in-site inspection of integrated devices.

By studying the effect of spatially induced group velocity dispersion (SIGVD) during the propagation of ultrashort pulsed Bessel beams in free space, we numerically prove that third-order SIGVD can temporally cause Gaussian distribution of pulsed Bessel beams to gradually evolve as unsymmetrical trailing oscillatory structures. The pulse shape is confirmed to be temporal Airy distributions on the basis of the cross-correlation function. Therefore, it is demonstrated that the scheme of generating spatiotemporally nonspreading Airy-Bessel wave packets in free space is possible by using a precompensating second-order SIGVD. The results of numerical simulation show that the quasi-Airy pulses induced by third-order SIGVD are temporally nonspreading during propagation in dispersive media. The reasons for nonspreading of such Airy distribution pulses are phenomenologically analyzed by a time-frequency Wigner distribution function of the pulse.

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