Light field

About: Light field is a research topic. Over the lifetime, 5357 publications have been published within this topic receiving 87424 citations.

Squeezing via coupling of Bose-Einstein condensates in a double-well potential with a cavity light field

Abstract: Squeezing via the interaction between the cavity light field and the Bose–Einstein Condensate (BEC) in a double-well potential is considered within the context of the two-mode approximation. For the cavity light field initially in a coherent state, it is shown that by choosing appropriate parameters, quadrature squeezing of the cavity light field can be achieved and it exhibits periodic oscillation. We also study the case in which BEC is tuned to resonance by periodically modulating the trapping potential, and the quadrature squeezing of the cavity field exhibits periodic collapse and revival effect. Both analytic and numerical calculations are performed, and they are found to be in good agreement with each other. The result shows that the quantum statistical properties of the cavity light field can be manipulated by its coupling with the condensates in the double-well potential. On the other hand, dynamical properties of the condensates in the double-well potential will be reflected by the quadrature squeezing of the light field.

Depth Estimation From Light Field by Accumulating Binary Maps Based on Foreground–Background Separation

Abstract: A three-dimensional (3-D) scene can be separated into two regions: foreground and background, which are regions in front of and behind the focused plane, respectively. From the 4-D light field, this paper proposes a depth estimation method by accumulating binary maps, which are computed by the foreground–background separation with light field reparameterization. In the proposed foreground–background separation, an optical phenomenon is used where bundles of rays from the background are flipped on their conjugate planes. Using the Lambertian assumption and gradient constraint, the foreground and background of a scene can be converted to a binary map by voting the gradient signs in every angular patch. Using light field reparameterization, the disparity map can be obtained by accumulating the binary maps. Finding the extremum index in the existing methods corresponds to finding the zero crossing index in the proposed method. By accumulating the binary maps, the proposed method has an advantage on the computational efficiency in terms of memory usage, and can use various reparameterization strategies suitable for applications. Experimental results with synthetic and real images show that the proposed method can generate a high-quality disparity map.

Waveguides and directional coupler induced by white-light photovoltaic dark spatial solitons

Abstract: We have observed experimentally, for the first time to our knowledge, one-dimensional photovoltaic dark spatial solitons in LiNbO3:Fe crystal by using incoherent white light. We have also fabricated a directional coupler consisting of two waveguides induced by two mutually incoherent white-light photovoltaic dark spatial solitons propagating in parallel in close proximity. It was found that the light field of a probe laser beam launched into one of the two proximate waveguides can be efficiently coupled into the other waveguide because of the presence of evanescent waves. We also studied the dependence of the coupling efficiency on the distance between the two proximate soliton-induced waveguides.

Angular color variation in micron-scale light-emitting diode arrays.

Abstract: A simulation scheme was developed to explore the light distribution of full-color micron-scale light-emitting diode (LED) arrays. The influences of substrate thickness, patterning, and cutting angle of the substrate on several important features, such as light field pattern, light extraction efficiency, and color variation, were evaluated numerically. An experiment was conducted; the results were consistent with simulation results for a 225 × 125 µm2 miniLED and those for an 80 × 80 µm2 microLED. Based on the simulation results, the light extraction efficiency of LED devices with a substrate increases by 67.75% over the extraction efficiency of those without a substrate. The light extraction efficiency of LED devices with a substrate increases by 113.55% when an additional patterned design is used on green and blue chips. The calculated large angle Δu′v′ can be as low as 0.015 for miniLED devices.

Joint Blind Motion Deblurring and Depth Estimation of Light Field

Abstract: Removing camera motion blur from a single light field is a challenging task since it is highly ill-posed inverse problem. The problem becomes even worse when blur kernel varies spatially due to scene depth variation and high-order camera motion. In this paper, we propose a novel algorithm to estimate all blur model variables jointly, including latent sub-aperture image, camera motion, and scene depth from the blurred 4D light field. Exploiting multi-view nature of a light field relieves the inverse property of the optimization by utilizing strong depth cues and multi-view blur observation. The proposed joint estimation achieves high quality light field deblurring and depth estimation simultaneously under arbitrary 6-DOF camera motion and unconstrained scene depth. Intensive experiment on real and synthetic blurred light field confirms that the proposed algorithm outperforms the state-of-the-art light field deblurring and depth estimation methods.