An apparatus and method for obtaining Raman spectra that are suitable for continuous real-time monitoring, utilizing the basic technique of Raman spectroscopy in cooperation with wavelength-selective optical amplification are described. The invention improves the detection sensitivity of conventional Raman spectroscopy by orders of magnitude by providing strong wavelength-selective optical amplification and narrowband detection of the intense driving laser and the weak Raman signal(s), thereby essentially eliminating the driving laser signal from the detector and detection electronics. The invention is effective for both Stokes and anti-Stokes Raman lines, and either where the incident laser wavelength is fixed and the Raman spectrum is recorded by analyzing the output of the fiber amplifier with a spectrometer, or where the detection wavelength is fixed and the Raman spectrum is recorded by tuning the wavelength of the laser.