A new underwater imaging method and apparatus has been created and designed. The method is utilizing multibeam interference and is implemented in the following way. First, using mode-locked laser to shoot short light pulse into a mirrored negative dispersion device. Due to dispersion, the pulse width is broadened, that is, the multi-beams formed by pulse spectral components will create destructive interference in the device to reduce their combined intensity. Then, these multi-beams go into the water. Since their combined intensity has been reduced, the water absorption and scattering are reduced too because the water absorption and scattering are all directly proportional to the combined intensity of the multibeams. Because the water dispersion is positive, the beams with lower frequencies will travel faster in the water which is opposite to what happened in the negative dispersion device. Thus, the width of the broadened light pulse is compressed gradually in the water. If the dispersive characteristic of the mirrored negative dispersion device is designed to match that of the water reversely well, the broadened light pulse can be compressed ideally in the water at a special position. In other words, the multiple beams will create constructive interference to produce a combined intensity maximum in the water, which will form an internal light layer to illuminate the object. The theoretical calculations have proved feasibility of the method and show that the designed apparatus can increase imaging distance in clean ocean water to much more than 100m with possibility of even to 1000m.
A novel medical imaging method has been created with theoretical demonstration for its feasibility. The method uses multi-beam interference to create destructive interference in the propagation path to reduce composite light intensity and so reduce light absorption and scattering, and to create constructive interference at a designed position to produce composite light intensity maximum which forms an internal light layer to illuminate the target tissue. This method can enhance signal strength more than 600dB. The imaging depth can be over 5cm in human body. The imaging resolutions are less than1μm along object plane and near1μm along direction of depth of field.
KEYWORDS: Data storage, Polarization, Reflectivity, Beam splitters, Diffraction gratings, Digital video discs, Absorption, Signal to noise ratio, Optical filters, Refractive index
An optimized six-dimensional storage system has been investigated theoretically. The system uses multiple beams to create overlapped micro gratings as each storage cell. The cell capacity depends exponentially on the beam wavelength number. With two-photon absorption writing, coherence tomography reading and superresolving beam focusing, this system has extra-large capacity of >1 Pbyte per DVD sized disk (potential ~60 Pbytes per disk), extra-fast reading speed of >117 Gbits/s with high signal-to-noise ratio of >66 dB, large cell sizes (~0.3μm × 6μm) which greatly reduce data addressing difficulties and a standard drive like structure compatible with the CD and DVD disks.
KEYWORDS: Polarization, Reflectivity, Data storage, Beam splitters, Absorption, Digital video discs, Diffraction gratings, Signal to noise ratio, Refractive index, Optical storage
An optical storage system which stores data in three spacial and three physical dimensions is designed and investigated.
Its feasibility has been demonstrated by theoretical derivation and numerical calculation. This system has comprehensive
advantages including very large capacity, ultrafast throughputs, relatively simple structure and compatibility with CD
and DVD. It’s an actually practicable technology. With two-photon absorption writing/erasing and optical coherence
tomography reading, its storage capacity is over 32 Tbytes per DVD sized disk, and its reading speed is over 25 Gbits/s
with high signal-to-noise ratio of over 76 dB. The larger capacity of over 1 Pbyte per disk is potential.
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