Frequency–phase locking of a $CH_3OH$ laser $(\lambda=70,5\mu m)$ to a ${}^{13}C^{16}O_2$ laser

The emission frequency of a submillimeter $CH_3OH$ laser $(\lambda=70,5\mu m)$ was frequency–phase locked to a ${}^{13}C^{16}O_2$ laser $(\lambda=10,07\mu m, P(28))$ and the ${}^{13}C^{16}O_2$ laser was locked to a ${}^{12}C^{16}O_2$-laser $(\lambda=10,2\mu m, R(30))$, which made it possible to transfer the frequency characteristics of a highly stable $He-Ne/CH_4$ laser to the submillimeter range.