optical spectroscopy

Optical spectroscopy is the study of how matter absorbs and emits light and other radiation, analyzing these processes based on the radiation's wavelength. This technique is fundamental to many areas of physics, including quantum mechanics and relativity.1

Optical spectroscopy involves three main components: a light source, a disperser to separate light into wavelengths, and a detector. There are two primary types:2
* Absorption spectroscopy measures the loss of energy when light passes through a sample. Unique wavelengths absorbed by atoms or molecules can identify them.2
* Emission spectroscopy involves exciting a sample, which then emits radiation at specific wavelengths corresponding to energy differences within its quantum states. These characteristic "fingerprints" also identify the substance.2

Spectrometers use methods like diffraction gratings to disperse light, allowing for the analysis of different wavelengths. This sensitivity enables the detection of single atoms or trace contaminants and is crucial for understanding the composition of stars and interstellar molecules.31