628 research outputs found
Conoscopic holography
A new method for recording holograms using incoherent light is described. The method is based on optical propagation through birefringent crystals. Optical methods for the reconstruction of such a hologram are also presented
Spectral phase conjugation with cross-phase modulation compensation
Spectral phase conjugation with short pump pulses in a third-order nonlinear material is analyzed in depth. It is shown that if signal amplification is considered, the conversion efficiency can be significantly higher than previously considered, while the spectral phase conjugation operation remains accurate. A novel method of compensating for cross-phase modulation, the main parasitic effect, is also proposed. The validity of our theory and the performance of the spectral phase conjugation scheme are studied numerically
Spontaneous spectral phase conjugation for coincident frequency entanglement
Spontaneous parametric processes pumped transversely with short pulses are studied under a unified framework, which proves that such processes can efficiently generate entangled photon pairs with time anticorrelation and frequency correlation. Improvements upon previously proposed schemes can be made by the use of quasi-phase-matching, four-wave mixing, and cross-phase-modulation compensation. The use of frequency-correlated photons in the Hung-Ou-Mandel interferometer is studied
Real-time programmable acoustooptic synthetic aperture radar processor
The acoustooptic time-and-space integrating approach to real-time synthetic aperture radar (SAR) processing is reviewed, and novel hybrid optical/electronic techniques, which generalize the basic architecture, are described. The generalized architecture is programmable and has the ability to compensate continuously for range migration changes in the parameters of the radar/target geometry and anomalous platform motion. The new architecture is applicable to the spotlight mode of SAR, particularly for applications in which real-time onboard processing is required
Experimental characterization of an angle-multiplexed holographic memory
We demonstrate a simple angle-multiplexing holographic storage system, using a single acousto-optic deflector to achieve fast random access to the stored holograms. We used this system to store as many as 300 holograms in a 90 degree-geometry Fe:LiNbO3 crystal. To characterize the system performance, we analyzed the reconstructions in terms of the signal-to-noise ratio
Optical information processing based on an associative-memory model of neural nets with thresholding and feedback
The remarkable collective computational properties of the Hopfield model for neural networks [Proc. Nat. Acad. Sci. USA 79, 2554 (1982)] are reviewed. These include recognition from partial input, robustness, and error-correction capability. Features of the model that make its optical implementation attractive are discussed, and specific optical implementation schemes are given
Optofluidic Distributed Feedback Dye Lasers
We review our recent work on poly(dimethylsiloxane) (PDMS)-based optofluidic dye lasers using a guided wave distributed feedback (DFB) cavity. We show experimental results of single-mode operation, an integrated laser array, multiple color dye lasing, mechanical and fluidic tuning, and monolithic integration with microfluidic circuits. Potential applications and future directions are discussed
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