A light generating system comprising a first light generating device, a second light generating device, a first luminescent material, a window element, and a light mixing chamber, wherein: - the first light generating device is configured to provide first device light; wherein the first light generating device comprises one or more of a laser and a superluminescent diode; - the second light generating device is configured to generate second device light; wherein the second light generating device comprises a solid state light source; - the light mixing chamber is defined by the window element and reflective walls, wherein the reflective walls having an average reflectivity for the second device light of at least 50 %; - the window element comprises (i) a first window element part comprising the first luminescent material, wherein the first window element part is configured in a light receiving relationship with the first light generating device, and (ii) a second window element part, wherein the second window element part is translucent for the second device light, and wherein the second window element part is configured in a light receiving relationship with the second light generating device; wherein the first window element part and the second window element part are configured in thermal contact with each other; wherein the first window element part and the second window element part differ in material composition; - the first luminescent material is configured to convert at least part of the first device light into first luminescent material light; - the reflectivity of the second window part is selected from the range of 30 - 70 % for the second device light; and - wherein the second window element part does not comprise a luminescent material that is configured to convert the second device light. - the first light generating device is configured to provide first device light; wherein the first light generating device comprises one or more of a laser and a superluminescent diode; - the second light generating device is configured to generate second device light; wherein the second light generating device comprises a solid state light source; - the light mixing chamber is defined by the window element and reflective walls, wherein the reflective walls having an average reflectivity for the second device light of at least 50 %; - the window element comprises (i) a first window element part comprising the first luminescent material, wherein the first window element part is configured in a light receiving relationship with the first light generating device, and (ii) a second window element part, wherein the second window element part is translucent for the second device light, and wherein the second window element part is configured in a light receiving relationship with the second light generating device; wherein the first window element part and the second window element part are configured in thermal contact with each other; wherein the first window element part and the second window element part differ in material composition; - the first luminescent material is configured to convert at least part of the first device light into first luminescent material light; - the reflectivity of the second window part is selected from the range of 30 - 70 % for the second device light; and - wherein the second window element part does not comprise a luminescent material that is configured to convert the second device light.