ABSTRACT
In 1666, Sir Isaac Newton experimented with a beam of sunlight passed through a glass prism (Figure 12.1). He discovered that the beam of light could be split into a continuous spectrum of colors. A spectrometer is an instrument used to quantify light energies generated by a light source, passed through a material, or reflected off a surface. It is a powerful tool for diagnostics. The ability to cheaply and rapidly record diffuse reflectance spectra or fluorescence spectra also has the possibility of helping with medical diagnosis. For example, the pulse oximeter, the needleless glucose meter, and noninvasive detection of tumors are all ways of improving medical diagnosis.242,243 This chapter discusses the basic principles of spectrometers and explores medical applications. Topics include
• Beer’s law • Diffraction grating • Do-it-yourself (DIY) spectrometers • Spectrometer algorithm
In addition, we study urine test and drink inspection cases and explore the potential applications in backlighting through tissues.
