A helium-neon laser is pumped by electric discharge. What wavelength electromagnetic radiation would be needed to pump it? See the given figure below for energy-level information. | Homework.Study.com
PDF] Reproducibility of helium-neon laser wavelengths at 633 nm. | Semantic Scholar
Sam's Laser FAQ - Helium-Neon Lasers
Wavelength of Helium-Neon Laser by Using Double Slit Interference Pattern - YouTube