In this presentation, we will delve into the evolution of volume holographic optical elements (VHOEs), discussing their development alongside calculation models such as the VOHIL model. We will unveil a novel visualization scheme rooted in this model, aimed at elucidating Bragg diffraction within intricate volume holograms. Lastly, we will showcase the latest advancements in the application of VHOEs, particularly in the realm of lightguide-based Augmented Reality (AR) and Mixed Reality (MR) glasses.
Conventional calculation of performance based on M/# assumes the diffraction efficiency as a simple function of the material thickness. It ignores the three-dimensional distribution of refractive index, which contributes to different diffraction efficiency, and always leads to over-evaluation of the storage capacity. Therefore, we proposed an efficiency coefficient to calculate the diffraction efficiency per refractive index consumption.
High-efficiency diffusers play important roles in modern optical industry. The applications include back-light of television, uniform lighting, glare suppression, lighting decoration, and so on. In this paper, we develop optical volume diffusion plate using polycarbonate (PC) plate doped with silicon dioxide (SiO2) micro particle. The scattering distribution of diffusers is an important factor in the lighting design. Commercial detectors often measure the bidirectional scattering distribution function (BSDF) by a scanning and time-consuming method. We have proposed screen imaging synthesis (SIS) system in 2012, and it can easily measure the bidirectional transmittance distribution function (BTDF). In this paper, the optimized formula is presented to correct the vignetting effect and scattering effect caused by the screen. A quasi-Lambertian screen is made to enhance precision. Finally, we combine the SIS system with the rotation controller, and a semi-automatic measuring machine is built. The SIS generation can measure BSDF of the samples precisely and easily. In order to reduce glare problems and design a luminaire with uniform light distribution, we usually use diffusers to modulate the luminaire.
A study for the incidence geometry to extend the accepted incidence position is presented and demonstrated. High-speed and high-quality self-pumped phase conjugate mirrors (SPPCM) can be formed with a counter-direction incidence with respect to the master light for the Cat-SPPCM. In addition to a counter-directional Kitty-SPPCM, when the incidence position is changed, a Kitty-SPPCM with high-pass filtering and a different SPPCM similar to the Bridge-SPPCM can be found. The discovery of these three kinds of optical phase conjugators extends the accepted incidence position range and angle, helpful for applying the SPPCM in various new applications.
We summarize our theoretical study of the collinear volume holographic storage system. Simple formulas with direct physical concepts are developed under paraxial condition with scalar diffraction theory and VOHIL model, which are much helpful in figuring out the characteristics on point spread function (PSF) and the shift selectivity. Accordingly, effective system design is possible.
We use a paraxial approximating solution to calculate the point spread function of the collinear holographic storage system and show that the point spread function can be dramatically enhanced by the reference pattern with random binary phase modulation or random phase modulation.
We propose a paraxial solution for pixel shift selectivity, which can simulate the pixel shift selectivity in two
dimensions and in wide range easily. Thus, the effect of different reference patterns can be calculated in detail. From the
simulation result, we conclude that the pixel shift selectivity get worse for amplitude modulation reference patterns.
Making no modulation is the best reference pattern for pixel shift selectivity, however the point spread function will be
worst in this case. To get an optimum system in both pixel shift selectivity and point spread function, the reference
pattern with phase modulation will be the best choice.
KEYWORDS: Systems modeling, Process modeling, Switching, Video, Computer simulations, Visualization, Polonium, Switches, Video compression, Data modeling
This paper discusses disk system design that supports VCR-like interactive video-on-demand (VOD) with a good quality-of- service (QoS) guarantee. The guarantee of QoS is based on a practice that requires no higher data bandwidth to support a stream switching from the normal playback mode to a fast search mode while providing VCR-like visual feeling. The main issue studied in this paper is how to figure out the I/O bandwidth required in order to achieve a certain level of QoS. This paper presents a queueing model to tackle this problem and uses simulation to verify the validity of the queueing model. This paper also addresses the related implementation issues.
KEYWORDS: Data storage, Information operations, Compact discs, Silicon, Computer science, Information science, Computing systems, Ions, Video, Operating systems
This paper proposes a design procedure that exploits storage devices with different cost/bandwidth and cost/capacity ratios to build a hierarchical storage system for video-on- demand with minimum cost. The storage system is assumed to have two levels of hierarchy. The level-1 storage devices feature a low cost/bandwidth ratio and a high cost/capacity ratio. On the other hand, the level-2 storage devices feature a high cost/bandwidth ratio and a low cost/capacity ratio. The proposed procedure determines, with respect to overall system cost, which level of the hierarchy each program should be placed into. Based on the decisions, the designer then can figure out the appropriate configuration of the hierarchical storage system. The optimization target is to minimize the overall cost of the storage system.
KEYWORDS: Data storage, Head, Video, Computing systems, Computer science, Information science, Data archive systems, Feature extraction, Molybdenum, Time metrology
This paper studies the impact of different disk array configurations on the size of data buffer required to support video-on-demand. The study is based on a general two-level hierarchical disk array structure that provides both parallelism and concurrency. The study reveals that, for disk arrays with the same total number of disks, a higher degree of parallelism means that the minimum size of data buffer required is larger. This result provides valuable insight about how to organize the disk array in order to minimize system costs.
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