We report in this paper the direct sampling of a bandlimited signal in the Ka Band by optical means. The sampling approach that has been used was based on a photoconductive switch made from low-temperature grown GaAs. The Photonic sampler may be used to down sample RF signals to base band before further conversion in digital by an electronic ADC. Thanks to this approach, the usual frequency mixers used for downconversion are suppressed and replaced by the Photonic sampler. This very simple approach has a lot of benefits such as high level of integration, extremely low cost, no need of external electrical synchronization signals.