  We numerically analyze the use of intense entangled twin beams for
ultra-sensitive spectroscopic measurements in chemical and biological systems.
The examined scheme makes use of intense frequency-modulated (chirped)
entangled beams to successfully extract information about the intermediate
material states that contribute to the two-photon excitation of an absorbing
medium. Robustness of the presented method is examined with respect to the
applied intervals of the frequency chirp.
