  Optical two-dimensional Fourier-transformed (2DFT) spectroscopy is used to
study the coherent optical response of potassium vapor in a thin transmission
cell. Rephasing and non-rephasing spectra of the D1 and D2 transitions are
obtained and compared to numerical simulations. Calculations using the optical
Bloch equations gives very good agreement with the experimental peak strengths
and line shapes. Non-radiative Raman-like coherences are isolated using a
different 2DFT projection. Density-dependent measurements show distortion of
2DFT spectra due to pulse propagation effects.
