The 3D surface reconstruction is done by analyzing the deformation of the image of binary grating projected onto the relief of an object, after that, the phase of the deformed pattern is extracted by Fourier transform and unwrapping the phase. There are several techniques for image grating projection and one of them is the so called Talbot Effect that creates self-images of a binary gratings. In this work one of the self-image of a grating is used for projection on the relief of an object. The deformed image is captured by a camera and is analyzed by the proposed Extended Fourier Transform (XFT) algorithm. The XFT algorithm is and enhancement of the common FFT algorithm and allows an improvement in surface reconstruction. A comparison between the reconstructed surfaces using traditional FFT algorithm and the proposed XFT algorithm is presented.
Optical activity of some substances, such as chiral molecules, often exhibits circular birefringence. Circular
birefringence causes rotation of the vibration plane of the plane polarized light as it passes through the substance. In this
work we present optical characterization of honey as function of the optical activity when it is placed in a polariscope that
consists of a light source and properly arranged polarizing elements.
In this work we describe an experimental technique to measure the birefringence of the cellophane film that has good behavior as half wave retarder. This technique is achieved when the film is placed in a polariscope that consists of a light source and properly arranged polarizing elements and a system of fringes is observed. Using Jones formalism for the system the birefringence appears in the phase term of harmonic functions. Some experimental results are shown.
We show the optical characterization of a Polymer Dispersed Liquid Crystal which was made mixing Norland Optical
Adhesive No. 65®, nematic liquid crystal and crystal violet dye, deposited between two glass substrates with indium tin
oxide (ITO) as electrodes. In this device, we recorded low frequency (104 lines/mm) holographic gratings made with the
interference of two beams from an Ar laser at 515 nm in emission line. We measured the diffraction efficiency of the
gratings obtaining 2% when the grating was read with a beam from a He-Ne laser at 612 nm.
Holographic interferometer is used with a dye-doped photopolymer on one of its arms, the sample is radiated
simultaneously with two wavelengths, and measuring the pattern fringe displacement we can calculate the refraction
index changes. The photopolymer we use is a mix of Norland Optical Adhesive No. 65 and Crystal Violet dye deposited
between two glass plates making a cell of 220 microns thickness. The sample is radiated with a beam from an Ar-ion
laser at 515 nm; in the interferometer we employed a He-Ne laser at 633 nm in emission line. We show some
We propose the use of polyvinyl alcohol photosensitized with copper chloride dihydrated CuCl2(2H2O) as a photosensitive material for recording holographic gratings. We obtained different dissolutions changing concentration of photosensitive agent and varying their pH factor, refraction index, and optical density for each sample. We registered diffraction gratings by holographic methods. The behaviors of diffraction efficiency parameters of holographic gratings regarding the concentration of a photosensitive agent were analyzed. We show there exists a correspondence between the diffraction efficiency parameter with concentration change of CuCl2(2H2O). The low toxicity of this holographic recording material as well as its peculiar behavior, photosensitivity, and ability to conduct electricity, makes it attractive for production diffractive optical elements with bio-polymers.
In this work it is demonstrated that they can search holograms of type Fourier in real time, utilizing photosensitive
material of the polymeric Norland Optical Adhesive 65® ( NOA 65® ) which, it is mixed with the violet crystal dye
(CV); For the record of holograms we use He-Ne laser, of 5 mW of power, in λ= 598 nm spectral line, in the
reconstruction we obtains of diffraction efficiency of the 0,216 % in the order one, which almost does not present noise.
These holograms are of phase with modulation for index refraction.
The diffraction efficiency behavior of the holographic gratings recorded in photopolymers is due to several parameters
such as the monomer concentration, the dye quantity, etc. It has been reported that the absorption in photopolymers
depends of the beam intensity employed to record the holographic gratings, polymerization velocity, humidity,
temperature, etc. In this work we present a theoretical model of the diffraction efficiency behavior of holographic
gratings recorded in Norland Optical Adhesive No. 65 mixed with crystal violet dye as function of the temperature and
the power of the recorder beam. The model is compared with some experimental results.
The record of diffraction gratings in the material composed by Norland 65 (polymer) mixed with crystal violet;
describe changes in its diffraction efficiency that it shows the material when is exposed to times of exposition extended,
since 1 min to 3 hours, due to phase modulation change. They recorded the diffraction gratings in real time to an angle of
interference of 5°, utilizing He-Ne laser with 598 nm (yellow color), with efficiencies of diffraction η (%) between 0.71
and 2.10 % only in the order 1.
In this work we propose a phase material based in Polyvinyl Alcohol (PVA) and Crystal Violet (CV) deposited on a glass substrate with 10 &mgr;m of thickness. In this material we record holographic gratings using a &lgr;=612 nm and reconstruct the image with &lgr;=543.5 nm of He-Ne lasers; the diffraction efficiency was
0.0056% for the first order. The material no requires developing process and is very easy to make. Experimental results are shown.
In this work we propose a technique to measure micro displacements using Moiré patterns of Fresnel zone plates films. In this technique the pattern is placed on a mechanical mount and the displacements are measured counting the displaced fringes of an amplified moire image as the mount is moving.
We describe a technique for holographic storage by simultaneous angular multiplexing to obtain a large-scale
holographic memory. We recorded 72 objects at the same time in one point on holographic plate PFG-03M from
Slavich Co., using a He-Ne laser (λ = 633 nm). Each object is placed on a circular photographic transparency, separate
0.94 degree each one. The technique allows us simultaneous reconstruction of the 72 images without cross-talk. The
diffraction efficiency obtained at order one is 6%. Experimental results are shown.
We recorded real time holographic gratings in a photosensitive liquid material. This material is Norland Optical Adhesive (NOA 65(R) ) mixed with crystal violet dye (CV). The NOA 65(R) is a clear, colorless, liquid photopolymer that cures when is exposed to ultraviolet light (UV) but when is mixed with crystal violet becomes sensitive to visible region of the electromagnetic spectrum. To record the gratings we used the interference between two beams from a He-Ne, obtaining phase modulation gratings by refraction index changes. We use three different wavelength, λ = 633 nm, 612 nm and 594 nm for recording the gratings and its highest diffraction efficient was obtained when the grating was illuminated with a wavelength λ= 594 nm whose value was of 10.76 %. This mixture of NOA 65(R) and CV open the possibility to make diffractive elements.
We report new material to record holographic images in an organic polymer of sap plant (Aeonium Nobile) by conventional microlithographic techniques with ultraviolet light. The information of the mask is transferred like a polymerized regions modulation. It is a phase modulation by means of refraction index. The material is developed by itself by means of the well-known physical-chemical reaction of cured.
In this work we describe a lithographic technique for fabrication of Fresnel lenses. This technique is achieved using a photo mask and Norland Optical Adhesive No. 65. The main characteristics of this lens are his low cost and its flexibility due to the material. Some experimental results are shown.
In this work we propose a new technique to measure micro displacements using high frequency holographic gratings. In this technique the grating is placed on an object with micro displacement and these displacements are measured counting the displaced fringes of an amplified grating image as the object is moving.
We analyze diffraction gratings behavior recorded on a phase holographic emulsion. This emulsion is composed with resin and bromophenol blue dye (BPB) they have a diffraction efficiency (η) from 0.22 to 0.615% order, and their thickness are different in the holographic emulsion.
In this work we describe an experimental technique to measure the refraction index of the 3M PP2500 film which has good behavior as quarter wave retarder plate for λ=633 nm. This technique is achieved when two perpendicular linearly polarized beam from a Wollaston prism are incident on the thickness of the film. The beams were incident parallel to the fast axis to measure the ordinary refraction index and parallel to the slow axis to measure the extraordinary refraction index. Some experimental results are shown.
Characteristics as a blue clear appearance, viscous solution, odorless are some properties from Polyvinyl alcohol (APV), as a dry film it is clear transparent, shows high flexibility and it is a good insulator. This polymer does not contain double link then it does not have π orbital that permit an inherently conductivity when it is doped. However, can be doped with salts as nickel chloride hexahydrate NiCl26H2O constructing a good conductor polymer with a resistivity around 300Ω cm. This doped polymer shows high dependency to the oxygen molecule by its molecular form or its presence in the humidity of the atmosphere. If a high vacuum is applied in a reactor with the doped polymer the value of resistivity increases quickly. The material shows a light reduction of resistivity parameter when its temperature is increased. Finally the polymer doped maintains high flexibility opening new possibilities and applications.
Ring light distribution patterns emerging after illumination of a material that forms a conic beam can be obtained in diverse cases. There are some phenomena that produce such distributions without an artificially tailored or designed mask. This device is produced by intermixing and curing of conventional PDLC form by the combination of optical glue and the nematic liquid crystal E7. When the device is illuminated with a He-Ne laser, a ring diffraction pattern with a spot in the center is observed. It was observed experimentally that the radius of the projected ring decreased when we applied an external voltage to the device with the indium tin oxide electrodes. The voltage dependent variation in the radii of the rings can be understood as a change in the period of the concentric spiral following the direction of the applied field when a voltage is applied in this device.
The traditional way of making holograms requires the use of a coherent light source and also a special care on the experimental setup. Usually, the light beam from the source is split into two beams with intensities having a special ratio as the respective lengths of their optical paths. In this work we report a different approach based on the use of synchronized coherent light sources, where the traditional experimental setup is not required. We comment on the advantages of using this scheme over the traditional one.
The solution composed of bromocresol green (BCG) with rosin diluted in isopropyl alcohol. Its present as holographic recording element. Based in diffraction gratings recorded, over two parameter of recording, such as: different concentration BCG and rosin, and to different angle between the object beam and reference beam. This material if photosensitive to the blue light λ = 457 nm employed an Argon laser. Obtain in this gratings diffraction efficiencies the
order of 2.27%.
We show an electro optic linear polarizer for the visible spectrum region. The device is made of a CyberdisplayTM liquid crystal display (LCD) manufactured by Kopin Co. and a linear polarizer. The device can rotate from 0 to 70 degrees the linear polarization state of a beam. To control the polarization rotation, we displayed gray levels from 0 to 255 in a PC connected to the LCD. We present the complete characterization of our device and experimental results.
We show Ronchi grating made of cellophane; this device has the particularity of modulate the polarization state of an arbitrary polarizes source. The grating period can be designed to obtain two linear perpendicular polarization states, horizontal and vertical, or circular, right and left if the source has linear or circular polarization state respectively. With this grating, we can modulate or demodulate images for stereoscopic applications.
We present a description of the characteristics of a solution, which is photosensitive, composed of a resin and phenol red with isopropyl alcohol as the solvent. We have used this solution to record a diffraction grating with the aid of an Argon Ion laser thus obtaining phase gratings with a diffraction efficiency of the order of 1 percent with a resolution of 381 lines/mm. The main advantages of this solution are shown to be its low cost and ease of use.
We present a new material with potential application in holography. We have used a film of mixing ammonium dichromate with rosin resin diluted in isopropyl alcohol. This material can be easily elaborate in the laboratory. A phase grating in this material was recording using Argon-Ion laser at (lambda) equals 457 nm, showing good diffraction efficiency. This material is capable of high resolution when we record some diffraction gratings, observing 2,000 l/mm (grooves). A characteristic of the developed process is their simplicity, takes approximately 25 seconds.