  We have implemented the so-called $\lambda$-Zeeman technique (LZT) to
investigate individual hyperfine transitions between Zeeman sublevels of the Rb
atoms in a strong external magnetic field $B$ in the range of $2500 - 5000$ G
(recently it was established that LZT is very convenient for the range of $10 -
2500$ G). Atoms are confined in a nanometric thin cell (NTC) with the thickness
$L = \lambda$, where $\lambda$ is the resonant wavelength 794 nm for Rb $D_1$
line. Narrow velocity selective optical pumping (VSOP) resonances in the
transmission spectrum of the NTC are split into several components in a
magnetic field with the frequency positions and transition probabilities
depending on the $B$-field. Possible applications are described, such as
magnetometers with nanometric local spatial resolution and tunable atomic
frequency references.
