Fluorescence applications
Fluorescence has been widely applied in multiple different scientific areas.Fluorescence Spectroscopy measures the fluorescence of a material to learn about its chemical composition. Fluorescence can reveal not only the presence of a fluorescent molecule, but also information about it's environment.
Fluorescence Microscopy is a practice scientist use to observe the molecules within cells, and of cells within tissues. It is used to identify smaller structures such as microbes. Scientists link fluorescent tags to anti-bodies that attach to desired features in the cell to make them visible in a microscope.
Fluorescence Guided Surgery uses medications that cause different types of tisuse to become fluorescent. During surgery, the suregon can excite the fluorescence to make these tissues light up and make them visible. This can be used on blood vessels or nerves, so they are not accidentally damaged. It can also mark cancerous tissue that the surgeon needs to remove.

Different types of fluorescent proteins that can be used to label cells for microscopy.
Image credit: Erin Rod (Own work) CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0), via Wikimedia Commons
Image credit: Erin Rod (Own work) CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0), via Wikimedia Commons

Neuron under a microscope it is labaled with the protein beta-tubulin III with green fluorescence. Arond it are cells of a different type called astrocytes. they are labeled with a red fluorescent protein called GFAP.
Image credit: "What Do You Know about Fluorescence?." Teledyne Photometrics, 2 Mar. 2020, www.photometrics.com/learn/microscopy-basics/fluorescence-imaging.
Image credit: "What Do You Know about Fluorescence?." Teledyne Photometrics, 2 Mar. 2020, www.photometrics.com/learn/microscopy-basics/fluorescence-imaging.