A lighting device comprising: - a plurality of luminescent concentrators , each luminescent concentrator comprising an elongated light transmissive body having a first face and a second face wherein the distance between the first face and the second face defines a length (L) of the elongated body , the elongated body comprising one or more radiation input faces extending between the first face and the second face , and a radiation exit window , wherein the second face comprises said radiation exit window ; each elongated light transmissive body comprising a luminescent material configured to convert at least part of a pump radiation received at one or more radiation input faces into luminescent material light , and each luminescent concentrator configured to couple at least part of the luminescent material light out at the radiation exit window as converter light , - a plurality of light sources configured to provide light source light as first pump radiation to the radiation input faces of a plurality of first luminescent concentrators ; - said plurality of first luminescent concentrators , configured to provide first luminescent material light at the respective radiation exit windows of the first luminescent concentrators as first converter light , and configured to provide said first converter light as second pump radiation to one or more radiation input faces of a second luminescent concentrator ; and - said second luminescent concentrator , configured to provide second luminescent material light at the radiation exit window of the second luminescent concentrator as second converter light . - a plurality of luminescent concentrators , each luminescent concentrator comprising an elongated light transmissive body having a first face and a second face wherein the distance between the first face and the second face defines a length (L) of the elongated body , the elongated body comprising one or more radiation input faces extending between the first face and the second face , and a radiation exit window , wherein the second face comprises said radiation exit window ; each elongated light transmissive body comprising a luminescent material configured to convert at least part of a pump radiation received at one or more radiation input faces into luminescent material light , and each luminescent concentrator configured to couple at least part of the luminescent material light out at the radiation exit window as converter light , - a plurality of light sources configured to provide light source light as first pump radiation to the radiation input faces of a plurality of first luminescent concentrators ; - said plurality of first luminescent concentrators , configured to provide first luminescent material light at the respective radiation exit windows of the first luminescent concentrators as first converter light , and configured to provide said first converter light as second pump radiation to one or more radiation input faces of a second luminescent concentrator ; and - said second luminescent concentrator , configured to provide second luminescent material light at the radiation exit window of the second luminescent concentrator as second converter light . <EOS>