What is the wavelength of the ruby laser?

The wavelength of the ruby laser is 694 nm. This characteristic wavelength is significant because it falls within the red region of the visible spectrum. Ruby lasers, which utilize a synthetic ruby crystal as the lasing medium, emit light through a process called stimulated emission, and the 694 nm wavelength is a result of the energy transitions of chromium ions within the ruby. This specific wavelength is widely used in various applications, including cosmetic procedures and tattoo removal, due to its ability to be absorbed effectively by certain pigments. Other wavelengths listed do not correspond to the ruby laser and represent different types of lasers or wavelengths used in different contexts, illustrating the distinct properties of laser technologies.