Construction of a visible spectrophotometer for optical spectroscopy demonstrations

Abstract

In this paper, we describe the design and construction of a spectrophotometer of easy economic access that operates in the region of 300nm to 700nm as a proposal for qualitative and quantitative demonstrations of optical spectroscopy in physics courses of secondary education, undergraduate in physics, chemistry, biology, and some engineering. The spectrophotometer is made up off our basic elements: a slit, a 1000 lines/mm diffraction grating, a TSL1402R sensor, and an Arduino MEGA board. The light that passes through the slit is collimated by a first lens at a focal length of 5 cm. The collimated beam hits the diffraction grating of 1000 lines/mm, where it is diffracted and subsequently focused by a second lens (with a focal length of 5cm) for the sensor, which is controlled by the Arduino MEGA. The spectra were visualized in real time by the serial plotter of the Arduino IDE and subsequently analyzed by OriginLab. To demonstrate the potential of the spectrophotometer presented here, it was used to visualize the spectra generated by different light sources for domestic use. The spectraobtained with the proposed spectrophotometer compared to those obtained using a commercial spectrophotometer, showed quite similar results, thus demonstrating the performance of the spectrophotometer and concluding that the spectrophotometer operates satisfactorily to carry out future investigations.