Interference enhanced first-order Raman band of monocrystalline silicon

• Dominant Raman band of silicon was interference-enhanced in SiO2/Si structure.
• Transfer matrix formalism was used to calculate the enhancement factor.
• Analytical dependence was obtained of the enhancement factor on the SiO2 layer thickness.

In the present study we discuss how excitation and Raman scattered wave interference enhances the intensity of the dominant Raman band of silicon (520.7 cm–1) measured in backscattering configuration. We applied the formalism of the transfer matrix for a normal incident laser beam onto the SiO2/Si structure and proposed the calculation of the enhancement factor. We confronted theoretical values with an experiment on a prepared SiO2/Si structure. Twofold enhancement of the intensity of the 520.7 cm–1 band was achieved. Experimental results for low numerical apertures (0.25) are in agreement with theoretical predictions and the theory could be generalized to two-layered structures. For higher numerical apertures (0.75 and 0.95) the supposition of normal incidence is not valid any more, thus observable deviations are introduced to the enhancement factor.