Investigação e construção de uma cavidade de Fabry-Perot para análise espectroscópica

Abstract

Fabry-Perot Interferometers is an instrument used in many technology areas and science, in special atomic Experimental Physical area, it is used for spectroscopic analysis. For the physics, describing the frequency present in a spectrum has a great relevance, therefore brings more knowledge about particles interactions of the studied system. However, it is necessary that the Fabry-Perot interferometer used could be accurate enough to show the different frequencies of the spectrum that are being analyzed. This way, the general objective of this research is the construction of a Fabry-Perot Interferometers, to be used in spectral analysis. One Fabry-Perot’s was assembled with a free spectral range (FSR, in English, Free Spectral Range) of 6 GHz to separate the two lines of the fluorescence spectrum of cesium which are separated by 9 GHz. Thus, we described the physical conditions necessary to make it stable, the experimental methods adopted and the comparison with is predicted by theory. In the first moment, was analyzed the free spectral ranger and also the width of half height of the maximum intensity of the interference signal which is produced when we shine Laser light with variable frequency on the Fabry-Perot cavity. In a second moment, we kept the frequency and we vary the size of Fabry-Perot cavity through a crystal oscillator fixed in one of the cavity mirrors with the intention to use the Fabry Perot as a spectrum analyzer. Finally, was used a diffusor to simulate scattered light by vapor in order to verify the instrument’s limits in capturing diffuse light.