Abstract:

The final distribution of light intensity plays an important role in the laboratory practices carried out by the students of the Degrees in Physics and in Optics and Optometry. One of the main contents of that degree is the analysis of such distribution. This knowledge allows students to understand some theoretical aspects of the subject Optics II, which are often very abstract. Furthermore, our students acquire the necessary competence to link this knowledge with experimental verification. Therefore, it is essential that students visualize in detail the studied optical phenomenon considering that, in most cases, the value of relevant magnitudes is obtained from the treatment of those images. Traditionally, these intensity distributions are observed in real time, either on a screen or through a microscope when the image size requires it. The use of CCD cameras or the use of mobile devices in the teaching practices of the Optics II laboratory as a means of obtaining the final images is an advance in their development, since they can be stored and manipulated in a simple manner, facilitating their subsequent analysis and study.

This work focuses on the design and use of a basic interferential device, the Fresnel Bi-prism, for the obtaining and subsequent analysis of Young's interferential fringes, with a CCD camera coupled to a microscope and with a smart phone’s camera. Traditionally, in the laboratory practices of Optics II of the University of Alicante (and in most of the teaching laboratories) the laser is used as a source of illumination. This is due to its high coherence greatly facilitates the obtaining of the corresponding interferential figure. This study includes other types of sources such as an extensive source of white light (halogen lamp), a spectral lamp of Hg and a lamp of Na (quasi-monochromatic). This shows how, with the use of a series of color filters and a slit of variable width as the primary source, the spatial and temporal coherence of the source can be improved to achieve a visible interferential pattern. In this way, even though the concept of coherence of the source presents an indisputable mathematical complexity, a simple introduction is obtained in a way that can be useful to the students of the Degree in Optics and Optometry and the Degree in Physics of the University of Alicante.

Keywords:

Optics, smartphone, CCD, ICTs.