3-dimensional modelling of the DOEs formation in PVA/AA photopolymers

Abstract

Photosensitive materials and optical information processing technologies based on holographic and photonic techniques are suffering a huge improvement. Furthermore Spatial Light Modulators (SLMs) based on LCoS microdisplays (PA-LCoS) open new possibilities to modulate the wavefront of a light beam. The improving of the models of the photopolymers as optical recording material together with the modelling of PA-LCoS, high resolution reflective devices, make possible the generation and recording of Diffractive Optical Elements (DOE) on the photosensitive materials. This DOEs have many important applications in photonics, communications of optical information processing. Working with a setup based on a LCoS display as a master, we can store complex DOEs. We used in this work PVA/AA based on acrylamide with coverplating and index matching system to avoid the influence of the thickness variation on the transmitted light in the material. With the 3-Dimensional diffusion model we can predict the DOE properties before recording and optimize the recording time and the exposure dose. Experimental data is compared with the simulation results to evaluate the accuracy of our model to reproduce the recording of any kind of complex DOE onto a photopolymer. This allows us to choose the appropriate characteristics for the material depending on the application and evaluate the influence of different parameters involved in the DOE generation. In this work we evaluate the simulation of the recording of optical vortexes, axicons, fork gratings and diffractive lenses comparing with the results using our experimental setup .

Analysis of the recording of multifocal lenses in photopolymers for intraocular applications

“…Where u = a 2 /2λz is the axial reduced coordinate, λ = 632 nm, Φ(ζ) corresponds to the lens phase (2), z represents the axial distance from the material and ζ is the input plane spatial coordinate. This diffraction pattern will be introduced in our diffusion model 7 for to obtain the average modulation of the refractive index to compare the experimental data. On the other hand, the result obtained by our diffusion model, 7 is represented by the blue-dotted line in Figure 4.…”

“…This diffraction pattern will be introduced in our diffusion model 7 for to obtain the average modulation of the refractive index to compare the experimental data. On the other hand, the result obtained by our diffusion model, 7 is represented by the blue-dotted line in Figure 4. The main difference between the ideal and experimental curves lies in the decrease in the intensity of the first focal point f 2 .…”

“…5 Additionally, we validate a theoretical model to predict lens formation in PVA/AA photopolymers. [6][7][8][9] This numerical model allow us to obtain the average refractive index modulation due to the photopolymerisation process. To simulate the real material illumination we also include; low-pass filtering, refering to the 4F system employed experimentally, attenuation, absorption, holes formation, index matching system, etc.…”

Analysis of the recording of Fibonacci lenses using photopolymers with 3-D diffusion model

“…Photopolymeric materials provide us with an ideal scenario to register DOEs, due to their good phase modulation properties, which we have successfully modeled recently. This model describes the diffusion process inside the photopolymer [1,2]. Towether with non-local polymerization, light attenuation with depth and variations of the polymerization rate, such as is dealt with in [3].…”