Single-cycle-pulse generation in a coherently mode-locked laser with an ultrashort cavity

We theoretically investigate the possibility of a passive mode-locking regime in a two-section laser with an ultrashort cavity of the length around ten wavelengths of the medium resonant transition or even less. It is shown that such a regime is enabled through the coherent mode-locking phenomena arising due to the self-induced transparency when the gain and absorption bandwidths do not impose any restrictions on the duration of the generated pulse. Under such conditions, a laser with an ultrashort cavity could produce output pulses with the terahertz (THz) repetition rate and the duration up to a single optical cycle. Moreover, several scaling rules were derived, which allow for further shortening of the output pulse duration with the respective scaling of the media parameters.

Automated summary

This article theoretically investigates the possibility of achieving passive mode-locking in a two-section laser with an ultrashort cavity. It is shown that coherent mode-locking phenomena arising from self-induced transparency can enable the generation of output pulses with terahertz repetition rate and extremely short duration. Additionally, several scaling rules are derived to further shorten the pulse duration by scaling the media parameters.