The application of liquid-core! optical fiber (LCOF) in the measurement of Fourier transform Raman spectra (FTRS) can enhance the Raman spectra intensity 10(2)-10(3) times, and the minimal length of the optical fiber for yielding maximal Raman spectra intensity is the reciprocal of the optical fiber loss coefficient. By using LCOF, beta-carotene's 1520 cm(-1) Raman line and rhodamine's 1524 cm(-1) Raman line were observed in their CS2 Solutions. These two Raman lines come from the pi-pi* transition of the C=C vibration. As beta-carotene and rhodamine's concentrations decrease, their Raman lines move to long wavelength (red shift), their linewidths narrow and their molar gain coefficients increase. (C) 2004 Elsevier B.V. All rights reserved.