Quantum frequency standard utilizing the $E$ component of methane

A detailed description is given of a new infrared frequency standard utilizing a He–Ne laser which is stabilized by a power resonance resulting from saturated absorption of the $E$ component of the $\nu_3[P(7)]$ transition in the $^{12}$CH$_4$ methane molecule: it is called the He–Ne/CH$_{4(E)}$ laser. The results of an investigation into stabilizing its frequency are given. It is shown that the frequency shift due to variation of the saturating power is far less for this laser than it is for the well-known He–Ne/CH$_4$ laser based on the $F_2^{(2)}$ component. A preliminary estimate is given of the difference between the emission frequencies of two independent He–Ne/CH$_{4(E)}$ frequency standards.