A light emitting device (1) comprising a first light source (21) and a second light source (22), a luminescent element (4) comprising a first light input surface (41), a second light input surface (42), a light exit surface (43), a first further surface (44) and a second further surface (45), a first cooling assembly (5) and a second cooling assembly (6), the first cooling assembly (5) comprising a first cooling element (52) and a first light source board (51) on which one of the light sources is mounted, and the second cooling assembly (6) comprising a second cooling element (62) and a second light source board (61), on which the other one of the light sources is mounted, and the second cooling assembly (6) being arranged with a surface (621) in mechanical and thermal contact with the first further surface (44) of the luminescent element thereby forming a first interface and the first cooling assembly (5) being arranged with a surface (521) in mechanical and thermal contact with the second further surface (45) 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, RRMS, of the first further surface (44) and the second further surface (45) of the luminescent element being comprised in the interval 1 µm <； RRMS<； 5 µm.L'invention concerne un dispositif d'émission de lumière (1) comprenant une première source de lumière (21) et une seconde source de lumière (22), un élément luminescent (4) comprenant une première surface d'entrée de lumière (41), une seconde surface d'entrée de lumière (42), une surface de sortie de lumière (43), une première autre surface (44) et une seconde autre surface (45), un premier système de refroidissement (5) et un second système de refroidissement (6), le premier système de refroidissement (5) comprenant un premier élément de refroidissement (52) et une première plaque de source de lumière (51) sur
