Single Pumped Superluminal Laser

Superluminal lasers operate under the condition in which the average group velocity in the cavity exceeds the vacuum speed of light, or alternatively, the group index is between 0 and 1 [1]. It has been shown in previous works that the sensitivity of the lasing frequency of such a laser with respect to a change in its optical roundtrip due to an external perturbation is expected to be substantially larger than that of a conventional laser, with an enhancement factor which is inversely proportional the group index [2]. This property makes superluminal lasers highly attractive for various sensing applications, primarily for challenging tasks such as gravitational wave detection and navigation grade rotation sensing. The realization of superluminal lasers requires the presence of a narrow dip in the center of a broad gain profile. The depth and width of the dip must be tailored carefully to produce the required dispersion profile yielding the enhanced sensitivity.