  We consider theoretically how to extract mode dependent single photons from a
time/frequency multimode non-classical beam. To achieve this task, we calculate
the properties of sum frequency generation with a pulse shaped pump, taking
into account both temporal and spatial degree of freedom. We show that using a
non-collinear configuration it is possible to achieve a mode dependent weakly
reflective beam splitter, with Schmidt number compatible with photon extraction
for continuous variable regime tasks. We explicit the possible application to
the degaussification of highly multimode squeezed frequency combs.
