Abstract:
In recent years, there has been a revival in the use of stimulated Raman scattering (SRS) in spectroscopy. SRS can provide label-free vibrational imaging of molecules with a much higher sensitivity than spontaneous Raman spectroscopy. A big drawback to current SRS techniques is that they generally employ expensive systems. One such system is that used by Freudiger et. al. The aim of this thesis was an investigation into a laser system which should improve on the results given by Freudiger et. al., and do so at a much lower cost. The pump laser used in this work operates at 1064 nm and the probe laser is tunable over the range 1450 to 1650 nm, corresponding to the system operating over the region from 2500 to 3300 cm-1 within which there are a wealth of biological resonances. The characteristics of the final system are presented. During design of the source it was ensured that all of the requirements needed to promote the generation of a Raman signal were satisfied, however the system was unable to detect Raman resonances. Comparing the characteristics of the final system with the characteristics and results given by Freudiger et. al., it is apparent that the system should have been readily able to observe a Raman signal. The inability to achieve a repeat of these results despite all the necessary precursors being present points toward a significant discrepancy between the two sets of results which could be further investigated.