Amplitude characteristics of a helium-neon laser at λ = 0.63 μ in the region of strong interaction between two modes

Experimental and theoretical investigations were made of the amplitude characteristics of a laser with an inhomogeneously broadened line in the region of strong interaction between modes. A basically new method is proposed for the attainment of narrow resonances of width ~1% of the width of a homogeneous line and with ~100% contrast. These resonances can be used to stabilize the emission frequency of a laser. They are due to a strong interaction between modes and they can be attained in all the lasers that generate two or more longitudinal modes.