The invention relates to a light emitting device comprising a light source array which comprises a plurality of separately electrically controllable electric light sources which are arranged in a matrix structure or any other defined geometrical arrangement. Advantageously, the pixel pitch of the light source array is less than (500) nanometer. The invention further relates to an optical detection device comprising a light detection device, which is arranged for producing an electrical signal in response to light reaching a light detection side of the light detection device, and to a method for operating such an optical detection device. The invention further relates to a computer program with program coding means arranged for performing such a method.