Juan Carlos Ibarra-Torres

Holograms in polyvinyl alcohol photosensitized with CuCl 2 (2H 2 O)

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.

Dynamic diffraction ring projector by doped polymer-dispersed liquid crystal

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.

Holographic materials composed by rosin with ammonium dichromate

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.

Electro-optic modulator of polarization for the visible spectrum region

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.

Holographic material film composed by rosin with phenol red

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.

Fish gelatin and ammonium dichromate as photosensitive film

In this work we propose a phase material based on fish gelatin from Norland Products© mixed with ammonium dichromate deposited on a glass substrate. The photosensitive film has 110 mm thickness. In this material we record low frequency (264 lines/mm) holographic gratings using a λ=532 nm from an Ar laser and reconstruct the image with λ=594 nm from a He-Ne laser. The diffraction efficiency is approximately15% for the first order. The material no requires developing process and is very easy to make. Experimental results are shown.

Characterization of a PDLC mixed with crystal violet dye

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.

Refraction indexes of the polyester film 3M PP2500

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.

Ronchi retarder gratings as polarization modulators

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.

Measurement of optical activity of honey bee

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.