A light emitting device comprising: a first light source and a second light source, the first light source and the second light source being adapted for, in operation, emitting first light with a first spectral distribution, a luminescent element comprising a first light input surface, a second light input surface, a light exit surface extending in an angle different from zero to both the first light input surface and the second light input surface, a first further surface and a second further surface, the luminescent element being adapted for receiving the first light with the first spectral distribution at the first light input surface and the second light input surface, converting at least a part of the first light with the first spectral distribution to second light with a second spectral distribution, guiding the second light with the second spectral distribution to the light exit surface and coupling the second light with the second spectral distribution out of the light exit surface, the light emitting device further comprising a first cooling assembly and a second cooling assembly, the first cooling assembly comprising a first cooling element and a first light source board on which one of the first light source and the second light source is mounted, and the second cooling assembly comprising a second cooling element and a second light source board, on which the other one of the first light source and second light source is mounted; and characterized by: one of the first cooling assembly and the second cooling assembly being arranged with a surface (521 or 621) in mechanical and thermal contact with the first further surface of the luminescent element thereby forming a first interface and the other of the first cooling assembly and the second cooling assembly being arranged with a surface in mechanical and thermal contact with the second further surface of the luminescent element thereby forming a second interface, the first interface and the second interface comprising a flatness of less than 10 μm, and the root mean squared surface roughness, R RMS, of the first further surface and the second further surface of the luminescent element being comprised in the interval 1 μm < R RMS < 5 μm. a first light source and a second light source, the first light source and the second light source being adapted for, in operation, emitting first light with a first spectral distribution, a luminescent element comprising a first light input surface, a second light input surface, a light exit surface extending in an angle different from zero to both the first light input surface and the second light input surface, a first further surface and a second further surface, the luminescent element being adapted for receiving the first light with the first spectral distribution at the first light input surface and the second light input surface, converting at least a part of the first light with the first spectral distribution to second light with a second spectral distribution, guiding the second light with the second spectral distribution to the light exit surface and coupling the second light with the second spectral distribution out of the light exit surface, the light emitting device further comprising a first cooling assembly and a second cooling assembly, the first cooling assembly comprising a first cooling element and a first light source board on which one of the first light source and the second light source is mounted, and the second cooling assembly comprising a second cooling element and a second light source board, on which the other one of the first light source and second light source is mounted; and characterized by: one of the first cooling assembly and the second cooling assembly being arranged with a surface (521 or 621) in mechanical and thermal contact with the first further surface of the luminescent element thereby forming a first interface and the other of the first cooling assembly and the second cooling assembly being arranged with a surface in mechanical and thermal contact with the second further surface of the luminescent element thereby forming a second interface, the first interface and the second interface comprising a flatness of less than 10 μm, and the root mean squared surface roughness, R RMS, of the first further surface and the second further surface of the luminescent element being comprised in the interval 1 μm < R RMS < 5 μm. one of the first cooling assembly and the second cooling assembly being arranged with a surface (521 or 621) in mechanical and thermal contact with the first further surface of the luminescent element thereby forming a first interface and the other of the first cooling assembly and the second cooling assembly being arranged with a surface in mechanical and thermal contact with the second further surface of the luminescent element thereby forming a second interface, the first interface and the second interface comprising a flatness of less than 10 μm, and the root mean squared surface roughness, R RMS, of the first further surface and the second further surface of the luminescent element being comprised in the interval 1 μm < R RMS < 5 μm.