%0 Journal Article
%T Phase locking and spectral linewidth of a two-mode terahertz quantum cascade laser
%A Baryshev A.
%A Hovenier J.N.
%A Adam A.J.L.
%A Kašalynas I.
%A Gao J.R.
%A Klaassen T.O.
%A Williams B.S.
%A Kumar S.
%A Hu Q.
%A Reno J.L.
%J Physics Letters
%D 2006
%V 89
%F BaryshevA._etal2006
%O exported from refbase (https://db.rplab.ru/refbase/show.php?record=967), last updated on Mon, 06 Jul 2015 15:57:13 -0500
%X We have studied the phase locking and spectral linewidth of an ~ 2.7 THz quantum cascade laser by mixing its two lateral lasing modes. The beat signal at about 8 GHz is compared with a microwave eference by applying conventional phase lock loop circuitry with feedback to the laser bias current. Phase locking has been demonstrated, resulting in a narrow beat linewidth of less than 10 Hz. Under requency stabilization we find that the terahertz line profile is essentially Lorentzian with a minimum linewidth of ~ 6.3 kHz. Power dependent measurements suggest that this linewidth does not approach the Schawlow-Townes limit.