Polychromatic beam splitting by fractional stimulated Raman adiabatic passage

We propose and demonstrate a femtosecond laser inscribed micro-optical device for broadband beam splitting based on the interruption of the stimulated Raman adiabatic passage. For the spectral characterization waveguide fluorescence microscopy is applied by exciting nonbridging oxygen holes and exciton defects at several wavelengths. Additionally, spectrally resolved nearfield imaging shows octave spanning 50:50 beam splitting.