How do neon glow lamps produce their orange light?

Neon glow lamps and signs produce their characteristic orange-red light through a process known as gas excitation.12

When neon gas is confined within a glass tube at low pressure and subjected to an electrical current, the electrical energy excites the neon atoms, raising them into higher energy states. As these atoms subsequently decay back to their ground state, they release the absorbed energy in the form of photons, which manifests as the familiar orange-red glow.3142

This phenomenon is a specific application of the broader principle of electric discharge lamps, where noble gases are energized to emit light. While neon is responsible for the orange-red color, other gases or combinations can produce different colors; for example, mercury vapor produces a bluish light, and helium in amber glass can appear gold.34