Fluorescence based techniques are analytical techniques that utilize the property of fluorescence to identify and measure the presence of certain molecules or compounds within a sample. Using fluorescence, molecules can be illuminated with a short wavelength light and then identified by the emission of a longer wavelength light. These techniques are particularly useful in medical diagnostics, biomedical research, and environmental science due to their high sensitivity and specificity. Examples of fluorescence based techniques include fluorescence microscopy, flow cytometry, and fluorescence activated cell sorting.