This work addresses some key challenges in the fields of bio and nanophotonics by stimulated Raman microscopy. We present the design and the implementation of a femtosecond stimulated Raman scattering microscope, equipped with three femtosecond laser sources, which allows the coexistence of stimulated Raman gain (SRG) and stimulate Raman losses (SRL) detection modes in a single microscopy setup and to generate images of the same region in succession, without adding or removing components. In order to demonstrate the switching between the two detection modes, SRL and SRG images of polystyrene beads are acquired and the images quality are evaluated and compared.