The electromagnetic spectrum is usually classified by its wavelength and the energy levels associated with it. Teaching these relations to kids without an exploration activity could be a real challenge. On this subject, we have designed a lesson using lasers, diffractions gratings, and photoluminescent materials. This lesson includes activities that allow introducing different optics and photonics concepts. The warm-up activities are to learn the monochromatic nature of lasers, show how diffractions gratings work and explain the concepts of phosphorescence and fluorescence. All this knowledge is combined to see the different energy levels associated with three colors of lasers: red, green and violet. Using different lasers the kids explore which ones activate the fluorescence or phosphoresce effects in the materials provided and, finally, they examine these effects using diffraction gratings. The diffraction gratings allow exploring how a laser can cause fluorescence and how the light emitted by this phenomenon is related to the color of the laser and other colors with less energetic wavelengths. Also, the different lasers are used to analyze which one can cause phosphoresce over materials and comparing the violet lasers with the UV light. In the end, the conclusion is based on the law of conservation of energy.
The group Physics for everyone, a group created by former members of the SPIE student chapter of the Universidad Autonoma de Nuevo Leon, have been conducting activities for kids, teenagers and the general public through the program “Optics for everyone” since its creation in 2013. The objectives of this group and this program are to teach the importance of light, optics, and photonics to understand the world where we lived and the advances in technology. Also, the group prepares undergraduate students to learn and teach optics and photonics before taking the corresponding curricular courses, conducting to a new approach of how to understand the light interactively. This work presents a summary of the activities performed during five years, the outcomes obtained, the number of people reached, the experience of the volunteers and the conclusions and future work of the program and the group. Among the outstanding contributions of the programs is included the performance of optics and photonics workshops in public schools and public places, including unprivileged and remote communities in the state of Nuevo Leon, Mexico.
The objective of this work is present diverse ways to measure the impact and quality of the informal optics education activities for its improvement in content, quality and didactic techniques; including a list of recom- mendations about how to measure the impact of the outreach events, including the target audience and the staff involved. Also, for measuring the outcomes, it is added a list of techniques about how to know the best activities for each audience, understands the perception of the activity for the public and the application of quizzes based in QR technology for a quick outcome.
May 16th, 2018 was the first International Day of Light and the Universidad Autonoma de Nuevo Leon celebrated it with a project called "IDL in Monterrey: science, art and culture of light". The two main objectives of the project were: to offer guidance to basic education teachers about how to use hands-on activities related with light, optics, and photonics to teach science with low-cost materials and taking into account the application and impact of science in our daily light; and involve non-technical audience in the appreciation and learning of the sciences, technologies, and arts related to light, using artistic and scientific demonstrations and interactive activities. The project includes teacher training, science and art workshops, STEM exhibitions, theater play and talks about light and its importance in life, science, technology, art, and culture. The present work will include the outcomes of the event and the impact of the different activities carried out.
The efficiency in Fresnel lenses is affected by three principal sources: energy loss by absorption, chromatic dispersion and reflectance losses at refracting surfaces. On this subject, the design of nonimaging Fresnel lenses integrated by refractive and total internal reflection prisms is presented. This design method uses iterative calculations for design every prism and it selects the best option for avoid reflectance losses. A design and characterization of a Fresnel lens that takes chromatic aberration into account is shown, including a comparison with a nonimaging Fresnel lens composed only by refraction prisms is performed and with other integrated by only total internal reflection prisms. In addition, the study about how acceptance angle and the number of prisms affects the final transmittance of the lens is included.
Lightpipes are used for illumination in applications such as back-lighting or solar cell concentrators due to the high irradiance uniformity, but its optimal design requires several parameters. This work presents a procedure to design a square lightpipe to control the light-extraction on its lateral face using commercial LEDs placed symmetrically in the lightpipe frontal face. We propose the use of grooves using total internal reflection placed successively in the same face of extraction to control the area of emission. The LED area of emission is small compared with the illuminated area, and, as expected, the lateral face total power is attenuated. These grooves reduce the optical elements in the system and can control areas of illumination. A mathematical and numerical analysis are presented to determine the dependencies on the light-extraction.
The efficiency of sunlight collection systems is related to the optical element used as a collector. On this subject, the design of a nontracking solar collector that consists of a segmented nonimaging Fresnel dome is presented. It is formed by the conjunction of different zones for solar collection, where each one is a nonimaging Fresnel lens that collects a specific angular range (θin) of sunlight received in the northeast of Mexico, but the methodology presented can be easily extended to other geographic locations. The final design is a semistationary segmented collector with a 100-cm diameter and 50-cm focal length that needs a 180-deg rotation over the XY-plane in each equinox. The numerical simulations show that the nontracking segmented collector has a combined acceptance semiangle of θin=±105 deg with an average efficiency of over 67% from 9:00 to 18:00 h. The spatial and angular distributions of the sunlight collected are also included. This design has a collection area equal to that of a single nonimaging Fresnel lens with an acceptance semiangle of θin=±45 deg. These results are reproducible and provide valuable data for designing nontracking solar collectors based on nonimaging Fresnel lens.
The Fisica Pato2 (Physics 4 every1) outreach group started as a need of hands-on activities and active Science demonstrations in the education for kids, teenagers and basic education teachers in Nuevo Leffon maintaining a main objective of spread the word about the importance of Optics and Photonics; for accomplish this objective, since November 2013 several outreach events are organized every year by the group. The program Optics 4 every1 is supported by the Facultad de Ciencias Fisico Matematicas of the Universidad Autonoma de Nuevo Leon and the International Society for Optics and Photonics and consist in quick hands-on activities and Optics demonstrations designed for teach basic optical phenomena related with light and its application in everyday life. During 2015, with the purpose of celebrate the International Year of Light 2015, the outreach group was involved in 13 different events and reached more than 8,000 people. The present work explains the activities done and the outcome obtained with this program.
Extraction light in light-pipes with different specular surfaces was analyzed. In the analysis, the impact of the surface shape in all properties of the extracted light in order to obtain an efficient extraction and a uniform illumination using a LED as light source. Also, several parameters of the specular surface to obtain spatial uniformity inside the light-pipe are considered. In this case, the simulation was made for a rectangular lightpipe. One objective of this work is to compare how the front face shape of the specular surface can affect the extraction of light in the lateral face of the light-pipe, only straight and elliptical front faces were used in this work and the comparison between them at different tilts and lengths were made. The main purpose of the front face was extract the light uniformly at the lateral face and this was done by studying simulations on OpticStudio Zemax. The results show how the extraction length is lower in the elliptical front but its total power performs better than the line front.
The success of solar systems, such as photovoltaic and sunlight illumination systems, is principally determined
by the primary optical element used as collector. On this subject, the design of a segmented nonimaging Fresnel
lens is presented; this collector is formed by the conjunction of different zones for solar collection, where every
zone is made of a nonimaging Fresnel lens that collects a specific angular range of sunlight, according to the solar
radiation of the northeast received in Mexico. Every collector section focus in a common area. The different
zones are designed considering the apparent solar movement due to the daytime and the seasonal displacement
over the year. The collector total performance is presented, including spatial and angular distribution. The
collector presents an average performance over 80%, with an acceptance half-angle of 120°, and a collection area
similar to that in a collector with 45° of acceptance half-angle.
Homogenize light is the principal purpose of mixing rods. Light extraction from mixing rods is proposed by changing the shape of the face, the rod or a combination of both for many applications. Light extraction also can be done by its lateral face by cutting the Mixing rod. In this work a simulation of square and hexagonal poly(methyl methacrylate) (PMMA) mixing rods were made in Radiant Zemax ® 12 release 2 designed with an elliptical transversal cut to extract light from a lateral face. The cut is specular for rays that fulfill the total internal reflection condition, the reflected rays are deviated and the Total Internal Reflection (TIR) condition broken, then, extracted. An advantage of this cut is that it can be controlled in depth to extract the amount of light required and the remaining light used for other purposes. Also it can reduce the size of the mixing rods and optical components. For the simulation, an LED light were used as source, the light were homogenized by the mixing rod and due to it, the light extracted is also homogenous. The polar power map, radiant intensity and color of the light extracted are presented and compared in both mixing rods.
Among the main challenges for systems based in solar concentrators and plastic optical fibers (POF) the accuracy needed for the solar tracking is founded. One approach to overcome these requirements is increasing acceptance angle of the components, usually by secondary optical elements (SOE), however this technique is effective for photovoltaic applications but it has not been analyzed for systems coupled to POFs for indoor illumination. On this subject, it is presented a numerical analysis of a solar collector assembled by a Fresnel lens as primary optical element (POE) combined with a compound elliptical concentrator (CEC) coupled to POF in order to compare its performance under incidence angle direction and also to show a trade-off analysis for two different Fresnel lens shapes, imaging and nonimaging, used in the collector system. The description of the Fresnel lenses and its designs are included, in addition to the focal areas with space and angular distribution profiles considering the optimal alignment with the source and maximum permissible incident angle for each case. For both systems the coupling between the optical components is analyzed and the total performance is calculated, having as result its comparison for indoor illumination. In both cases, the systems have better performance increasing the final output power, but the angular tolerance only was improved for the system with nonimaging concentrator that had an efficiency over 80% with acceptance angles 𝜃𝑖 ≤ 2° and, the system integrated by the imaging lens, presented an efficiency ratio over 75% for acceptance angles 𝜃𝑖 ≤ 0.7°.
This work shows the results obtained from the “O4K” Project supported by International Society for Optics and Photonis (SPIE) and the Universidad Autonoma de Nuevo Leon (UANL) through its SPIE Student Chapter and the Dr. Juan Carlos Ruiz-Mendoza, outreach coordinator of the Facultad de Ciencias Fisico Matematicas of the UANL. Undergraduate and graduate students designed Optics representative activities using easy-access materials that allow the interaction of children with optics over the exploration, observation and experimentation, taking as premise that the best way to learn Science is the interaction with it. Several activities were realized through the 2011-2013 events with 1,600 kids with ages from 10 to 12; the results were analyzed using surveys. One of the principal conclusions is that in most of the cases the children changed their opinions about Sciences in a positive way.
We present a numerical analysis of different fiber termination shapes in order to study the maximum numerical aperture that can be obtained in end emitting plastic optical fibers with diameters around 10 mm. Our analysis includes the modeling of polished fibers with parabolic shape, conical lensed fibers, and wedged fibers with different lengths, angles and curvatures respectively. The optimization of these parameters allows us to obtain a maximum possible angle which the light can be emitted at the plastic fiber end. These results contribute to minimize the use of fiber components in luminaire systems which can be based in solar concentrators coupled to plastic optical fibers, and consequently it allows us to reduce their installation cost. We also analyze the light distribution of the emitted light and the optical tolerances of the parameters above mentioned to evaluate the performance of the optimized fiber lens. These results are of great interest for the improvement and design of compact luminaire systems based in optimized plastic fiber lens for indoor illumination.
We present an experimental characterization of a fiber laser composed by an Yb-doped fiber spliced with a birrefringent
photonic crystal fiber and a mechanically-induced long-period grating (LPG) into the laser cavity. According to the
torsion properties of the LPG induced in the photonic crystal fiber, the Yb-doped fiber laser can be highly sensitive to
twist and it can shown novel properties in its laser emission. Also, we show the splitting of attenuation bands of a longperiod
fiber grating induced mechanically in different twisted photonic crystal fibers with high birefringence and their
applications on the performance of tunable and switchable multiwavelength double-clad Ytterbium-doped fiber lasers.
The thermal effect of an Yb-doped fiber laser with fattening is numerically investigated. We have identified two principal sources of thermal sensitivity: The temperature dependence of the cross-section of the pump and signal radiations, and modifications of the numerical aperture (NA) due to changes in temperature. We have found that the first factor affects principally the thermal response of the fiber laser with fattening and this sensitivity can be modulated according to the fattening ratio. Additionally this thermal response is higher than that found in doped fibers without fattening. Our results are reproducible and contribute with new information for the development of novel temperature fiber laser sensors
This paper presents an optical fiber Mach-Zehnder interferometer configured as an ultra-sensitive sound detector.
We used a 633nm, 0.5 mW, He-Ne laser, two 3dB couplers, a few meter of telecomm fiber, an U-bench mount to
increase the sensitivity of the device and an acquisition system composed by a photodiode and an amplifier
connected to a laptop and to an oscilloscope. The optoelectronic device enables us to record acoustic signals from
sources at distances longer than 4 meters, converting the interference patterns induced by the sound waves into a
digital signal. The ease of its applicability, thanks to its small size and low weight, and its ultra-sensitivity makes
this laser microphone a very attractive solution to issues such as monitoring, no-detectable sensing and perimeter