Complex Modulation Characterization of Liquid Crystal Spatial Light Modulators by Digital Holographic Microscopy

Abstract

We study numerically the crossover between organized and disorganized states of three non-equilibrium systems: the Poisson/coalesce random walk (PCRW), a one-dimensional spin system and a quasi one-dimensional lattice gas. In all cases, we describe this crossover in terms of the average spacing between particles/domain borders S(t) and the spacing distribution functions p (n) (s). The nature of the crossover is not the same for all systems; however, we found that for all systems the nearest neighbor distribution p (0) (s) is well fitted by the Berry-Robnik model. The destruction of the level repulsion in the crossover between organized and disorganized states is present in all systems. Additionally, we found that the correlations between domains in the gas and spin systems are not strong and can be neglected in a first approximation, but for the PCRW the correlations between particles must be taken into account. To find p (n) (s) with n > 1, we propose two different analytical models based on the Berry-Robnik model. Our models give us a good approximation for the statistical behavior of these systems at their crossover and allow us to quantify the degree of order/disorder of the system.

Full Phase Encoding for Digital Holographic Encryption Using Liquid Crystal Spatial Light Modulators

“…The phase modulation of the LC-SLM devices were characterized in advance by the modified Mach-Zehnder interferometric architecture, in which the phase mode was obtained by setting the appropriate orientation of the front polarizer and back analyzer of the separate LC-SLM. 15) The experimental results for the phase modulation characteristics of each LC-SLM are shown in Fig. 4, in which 0-2 phase modulation is nearly obtained by setting various orientations of the front polarizer and back analyzer.…”

“…In this paper, we propose and demonstrate a full phase encoding technique for digital holographic encryption based on liquid crystal spatial light modulators (LC-SLMs). 13,14) LC-SLM devices are operated in the phase modulation mode 15) to perform the phase-encoded input object along with the double random phase masks in the object and reference arms, respectively, of an interferometric architecture. Owing to the fact that the primary image to be encrypted is phaseencoded into a phase object, the random key mask in the object arm can be treated as a phase diffuser as well as another key mask for optical encryption.…”

In situ Mapping of Light-Induced Refractive Index Gratings by Digital Holographic Microscopy

“…Atomic force microscopy achieves ultra high lateral resolution using a pointwise technique to generate a grating profile; however, the scanning mechanism may limit the capture rate of phase data and is unsuitable for non-destructive, full-field measurement of grating formation during the holographic recording process. Digital holography, [13][14][15][16][17][18][19][20][21] has been widely investigated and has great potential for applications such as measuring whole wavefronts of a sample because it can quantitatively assess all information in a complex wavefront (amplitude and phase) derived from a digital hologram. De Angelis et al 18) measured the refractive index profile of the phase grating in a lithium niobate (LiNbO 3 ) crystal plate using a digital holographic technique, which experimentally generated a direct observation of a grating profile in a recorded photorefractive crystal.…”

Online full-phase digital holographic encryption based on electrically addressed spatial light modulators

“…In this Letter, a novel full-phase digital holographic encryption scheme using electrically addressed liquid-crystal spatial light modulators (LC-SLMs) [11,12] for online optical processing is proposed and demonstrated. The LC-SLMs are operated in phase-modulation mode [13] to represent the phase-encoded input object and the double random-phase masks in the object and reference arms. Owing to the fact that a primary image to be encrypted is phaseencoded into a phase object, the random-phase mask in the object arm can be treated as the role, of a phase diffuser the other key mask being for optical encryption.…”