Complex sentence: Being a special variant of the multiphoton fluorescence microscope, it uses red-shifted excitation light which can also excite fluorescent dyes, however for each excitation two photons of the infrared light are absorbed.
Split into simpler sentences: Being a special variant of the multiphoton fluorescence microscope, it uses red-shifted excitation light which can also excite fluorescent dyes. However for each excitation two photons of the infrared light are absorbed.