  A near-infrared laser generates gain on transitions between the
$\text{B}^{\text{2}} \Sigma_{\text{u}}^{\text{+}}$ and $\text{X}^{\text{2}}
\Sigma_{\text{g}}^{\text{+}}$ states of the nitrogen molecular cation in part
by coupling the $\text{X}^{\text{2}} \Sigma_{\text{g}}^{\text{+}}$ and
$\text{A}^{\text{2}} \Pi_{\text{u}}$ states in the V-system. Traditional time
resolved pump-probe measurements rely on post-ionization coupling by the pump
pulse to initialize dynamics in the $\text{A}^{\text{2}} \Pi_{\text{u}}$ state.
Here we show that a weak second excitation pulse reduces ambiguity because it
acts only on the ion independent of ionization. The additional control pulse
can increase gain by moving population to the $\text{A}^{\text{2}}
\Pi_{\text{u}}$ state, which modifies the lasing emission in two distinct ways.
The presence of fast decoherence on $\text{X}^{\text{2}}
\Sigma_{\text{g}}^{\text{+}}$ to $\text{A}^{\text{2}} \Pi_{\text{u}}$
transitions may prevent the formation of a coherent rotational wave packet in
the ground state in our experiment, but the control pulse can reverse impulsive
alignment by the pump pulse to remove rotational wave packets in the
$\text{B}^{\text{2}} \Sigma_{\text{u}}^{\text{+}}$ state.
