Helium-neon is a type of gas laser that uses a mixture of helium and neon gases to produce a coherent light beam. It typically emits light at a wavelength of 632.8 nanometers, which appears as a bright red color. These lasers are commonly used in applications such as laser pointers, barcode scanners, and optical devices. The helium-neon laser operates by exciting the gas mixture with an electrical current, causing the atoms to emit photons. This process creates a focused and stable light source, making it useful in various scientific and industrial applications, including holography and laser engraving.