Skip to main content
UploadLanguage (EN)Support
BusinessMobileSocial MediaMarketingTechnologyArt & PhotosCareerDesignEducationPresentations & Public SpeakingGovernment & NonprofitHealthcareInternetLawLeadership & ManagementAutomotiveEngineeringSoftwareRecruiting & HRRetailSalesServicesScienceSmall Business & EntrepreneurshipFoodEnvironmentEconomy & FinanceData & AnalyticsInvestor RelationsSportsSpiritualNews & PoliticsTravelSelf ImprovementReal EstateEntertainment & HumorHealth & MedicineDevices & HardwareLifestyle
eMadrid network, profile picture
Uploaded byeMadrid network
PPTX, PDF888 views

2011 06 02 (uned) emadrid mlcalvo ucm m learning y holografia tecnicas compatibles

The document discusses using mobile phones and holography for educational purposes. It proposes using the cameras in ubiquitous mobile phones to capture holograms and diffraction patterns created using classroom tools like laser pointers. Experiments were conducted capturing images from 1-3 meters away, and analyzing the results. The technique provides an accessible way for students to study optical phenomena. Combining this approach with digital holography and computational analysis offers potential for a portable lensless microscope or imaging device using only a phone. In conclusion, mobile phones provide a unique tool when combined with lasers to demonstrate diffraction concepts in the classroom with minimal infrastructure.

Business◦Technology◦
Download to read offline
m-Learning and Holography: Compatible techniques?María L. CalvoDepartamento de Óptica, Facultad de Ciencias Físicas, Universidad Complutense de Madrid (UCM)II Jornadas eMadrid sobre e-Learning, UNED, 1-2 junio 2011
OutlineIntroduction: What is m-Learning?Objectives.What is a hologram?In-line Gabor hologramThe concept of diffraction: Fresnel zonesClassroom accessibility: some resultsOther proposals.References.II Jornadas eMadrid sobre e-Learning, UNED, 1-2 junio 2011
Introduction: m-LearningImage sensors consists of devices that capture an image for purposes of display or storage.Cell phones are nowadays ubiquitous.Camera phones comprised over 80% of all shipped image sensors in 2008, with recent growth coming from the continuing penetration of dual-camera phones in the global market.Improvement of the technical design provides in 2011 cell phones with resolution of the order of 8 Mpixels (digital camera resolution).These facts provide unique tools for teaching and technological tools.II Jornadas eMadrid sobre e-Learning, UNED, 1-2 junio 2011
[Source: Wikipedia]
ObjectivesExperimental methods for studying the basis of optical phenomena are needed to be extended to class room as a routine tool for students in physics and engineers.These methods can be simplified and easily implemented by the use of the new technical assistance provided by camera phones: classroom accessibility. In 2009, Z. Ben Lakhdar et al. introduced a procedure for studying diffraction and interference by the use of overhead projectors and camera phone image capture.All tools accessible in the class room by the students.This technique can be extended to other optical phenomena, such as Holography.Some discussions arise after the analysis of the experimental results.II Jornadas eMadrid sobre e-Learning, UNED, 1-2 junio 2011
Antecedents: HolographyVolume holography developed by Y. Denisyuk(1962) as an extension of the pioneering experiments done by D. Gabor in 1947 (Nobel Prize, 1971) combined with the principles of color photography earlier obtained by G. Lippmann(1894).
C.V.Raman and N.S.N.Nath obtained evidence of thin grating behavior of an acoustic wave irradiated with light and studied the nature of the diffracted field in 1935.
During 20th century an important amount of work was done to introduce new techniques such as digital holography (A. Lohman, J. W. Goodman).
The 21st century is called to be the century of information photonics in which holographic techniques appear to be among the most appealing ones.C. V. Raman in his laboratory ca. 1930.II Jornadas eMadrid sobre e-Learning, UNED, 1-2 junio 2011
What is a hologram?Real imageA hologram is an interferogram in which it is encoded the amplitude and phase associated to the light wave diffracted by an object (object wave).The encoded information can be retrieved by the light wave diffracted by the hologram (reading the hologram). Virtual image II Jornadas eMadrid sobre e-Learning, UNED, 1-2 junio 2011
In-line holography: Gabor hologramReal image planeII Jornadas eMadrid sobre e-Learning, UNED, 1-2 junio 2011
Example: digital in-line holographic microscopyHolograms generated with agreen LED Reconstructed holographic imagesImages obtained with a Nikon Eclipse TE300inverted microscopeSet-up for a lensless digital holographic microscope with LED illumination.From: L. Repetto, E. Piano, and C. Pontiggia,Lensless digital holographic microscope with light-emitting diode illumination, Opt. Letters, Vol. 29, No. 10, 1132 (May 15, 2004) II Jornadas eMadrid sobre e-Learning, UNED, 1-2 junio 2011
SomehistoryondiffractionexperimentsIn 1665 Francesco M. Grimaldi (an Italian Jesuit, Bolonia, 1618-1663), developed a simple experiment with a light source (a candle), a slit and a screen. sourceHe was one of the earliest physicists to suggest that light was wavelike in nature. He formulated a geometrical basis for a wave theory of light in his work: “Physicomathesis de lumine, coloribus, et iride, aliisqueannexis” (Bolonia, 1665). He coined the term diffraction.Grimaldi’s experiment was disseminated by HonoreFabri (1607-1688). His publications (1669) allowed Isaac Newton to know on these antecedents. SlitScreen
Scheme for the diffraction of a laser beam by a circular aperturexmapertureLaser cavityDetection plane XY (Screen)RCamera phoneFresneldiffractionplane: FresnelZoneII Jornadas eMadrid sobre e-Learning, UNED, 1-2 junio 2011
Fresnelzones: definitionArea of Fresnel zone number-n:Generally, it is assumed that all areas of the regions are similar ones.II Jornadas eMadrid sobre e-Learning, UNED, 1-2 junio 2011
Fresnel lens hologramFrom: S. S. Sarkar, P. K. Sahoo, H. H. Solak, C. David, J. F. van derVeen, Fresnel zone plates made by holography in the extreme ultraviolet region, Journal of Physics: Conference Series, 186 012071 (2009).
SomeResults:Operating in theclassroomII Jornadas eMadrid sobre e-Learning, UNED, 1-2 junio 2011
Operating in the classroomWe need a white screen.
Students carry the camera phones.
We need a metric tape.
We need two types of laser pointers. To compare data: One emitting in green light another emitting in red light.
Pictures are taken at fixed distances from the screen.Laser pointers have to be handled with caution. Radiation can be hazardous to eyes.Output power: From 1 to 400 mW/cm2.II Jornadas eMadrid sobre e-Learning, UNED, 1-2 junio 2011
Propagationdistance: 1 m. Red laser pointer (l= 632 nm)Image as captured by the camera phone. Type: P3450 (CMOS camera)Line profileIntensity: 256 gray levels(8 bits)1pixel: 29 mm.pixels pixelsII Jornadas eMadrid sobre e-Learning, UNED, 1-2 junio 2011
Propagationdistance: 1m. Green laser pointer (l = 532 nm.)Image as capturedbythe camera phone.Line profilepixelspixelsII Jornadas eMadrid sobre e-Learning, UNED, 1-2 junio 2011
Propagationdistance 3 m. Red laser pointer (l = 632 nm)Image as captured by the camera.Line profilepixels pixels II Jornadas eMadrid sobre e-Learning, UNED, 1-2 junio 2011
Propagationdistance: 3m. Green laser pointer (l = 532 nm.)Image as captured by the camera phoneLine profilepixels pixelsII Jornadas eMadrid sobre e-Learning, UNED, 1-2 junio 2011
1 m. propagation diffraction regimesFFT Intensity FFT Phase FFT Intensity FFT PhaseII Jornadas eMadrid sobre e-Learning, UNED, 1-2 junio 2011
3 m. propagation diffraction regimesFFT Intensity FFT Phase FFT Intensity FFT PhaseII Jornadas eMadrid sobre e-Learning, UNED, 1-2 junio 2011
Results with another camera phone modelModel: Nokia 8600 LunaResolution: 1200x1600 400 pixels/cm.Original captured images:1200x1600After image treatment for line profile obtention: 150x150 pixels.Pixel: 25 mmII Jornadas eMadrid sobre e-Learning, UNED, 1-2 junio 2011
Green laser pointerpropagation distance: 242 cmImage as captured by the camera phoneImage treated with falsh color for line profileII Jornadas eMadrid sobre e-Learning, UNED, 1-2 junio 2011