Dispersion Enhanced Laser Frequency Response via Four-wave Mixing in an Active Cavity

Lasers are used for precision metrology, and by introducing a dispersive medium into the cavity, one can drastically enhance the sensitivity of such devices. We present experimental results demonstrating enhanced and suppressed lasing-frequency response to cavity-length variations in an active ring laser. Pumping on an N-type level scheme in $^{87}$Rb, we tune the cavity dispersion by varying experimental parameters, such as pump-laser frequency, atomic density, and pump power. As a result, we can control the sensitivity of the laser so that the lasing-frequency response to the empty cavity length change is increased greater than a factor of 2 in the enhanced regime and completely eliminated in the suppressed regime.