  We demonstrate the realization of the resonant spin amplification (RSA)
effect in Faraday geometry where a magnetic field is applied parallel to the
optically induced spin polarization so that no RSA is expected. However, model
considerations predict that it can be realized for a central spin interacting
with a fluctuating spin environment. As a demonstrator, we choose an ensemble
of singly-charged (In,Ga)As/GaAs quantum dots, where the resident electron
spins interact with the surrounding nuclear spins. The observation of RSA in
Faraday geometry requires intense pump pulses with a high repetition rate and
can be enhanced by means of the spin-inertia effect. Potentially, it provides
the most direct and reliable tool to measure the longitudinal $g$ factor of the
charge carriers.
