Observation of far-infrared emission from excited cytosine molecules

Y. C. Shen, P. C. Upadhya, E. H. Linfield, A. G. Davies
2005 Applied Physics Letters  
We report a time-resolved investigation of the resonant absorption of far-infrared radiation and the subsequent vibrational relaxation processes in a sample of polycrystalline cytosine at 4 K, using terahertz time-domain spectroscopy. The subpicosecond time resolution achieved in our experiments corresponds to a near single-cycle of far-infrared radiation, and this enables us to observe the damped oscillations of the electric field produced by excited molecules as they decay. Furthermore, we
more » ... w that the progressive absorption and subsequent emission of far-infrared radiation at the frequency of the corresponding vibrational mode can be followed directly as a function of time by means of time-partitioned Fourier transforms of the transmitted signal.
doi:10.1063/1.1968412 fatcat:emtkwoqvlvgdrm2ugktyjmzfae