A luminaire module comprising: one or more light-emitting elements (LEEs) (110; 210) arranged to provide light; and a light guide (130; 230) comprising: a receiving end and an opposing end, the receiving end arranged to receive the light provided by the LEEs, a pair of opposing side surfaces (132a, 132b; 232a, 232b) extending along a length of the light guide between the receiving end and the opposing end, the light guide configured to guide the received light in a forward direction, along the length of the light guide to the opposing end of the light guide, and wherein the light guide further comprises: a redirecting end-face (240; 240a-240d) located at the opposing end and configured to reflect at least a portion of the guided light - that reaches the opposing end - back into the light guide as return light, such that substantially all the return light impinges on the pair of opposing side surfaces at incident angles (142a; 142b) smaller than a critical incidence angle and transmits through the pair of opposing side surfaces into the ambient as output light of the luminaire module, the output light to propagate in backward directions, characterized in that the redirecting end-face (240; 240a-240d) is further configured to transmit another portion of the guided light - that reaches the opposing end - through the redirecting end-face in the forward direction into the ambient as output light one or more light-emitting elements (LEEs) (110; 210) arranged to provide light; and a light guide (130; 230) comprising: a receiving end and an opposing end, the receiving end arranged to receive the light provided by the LEEs, a pair of opposing side surfaces (132a, 132b; 232a, 232b) extending along a length of the light guide between the receiving end and the opposing end, the light guide configured to guide the received light in a forward direction, along the length of the light guide to the opposing end of the light guide, and wherein the light guide further comprises: a redirecting end-face (240; 240a-240d) located at the opposing end and configured to reflect at least a portion of the guided light - that reaches the opposing end - back into the light guide as return light, such that substantially all the return light impinges on the pair of opposing side surfaces at incident angles (142a; 142b) smaller than a critical incidence angle and transmits through the pair of opposing side surfaces into the ambient as output light of the luminaire module, the output light to propagate in backward directions, characterized in that the redirecting end-face (240; 240a-240d) is further configured to transmit another portion of the guided light - that reaches the opposing end - through the redirecting end-face in the forward direction into the ambient as output light a receiving end and an opposing end, the receiving end arranged to receive the light provided by the LEEs, a pair of opposing side surfaces (132a, 132b; 232a, 232b) extending along a length of the light guide between the receiving end and the opposing end, the light guide configured to guide the received light in a forward direction, along the length of the light guide to the opposing end of the light guide, and wherein the light guide further comprises: a redirecting end-face (240; 240a-240d) located at the opposing end and configured to reflect at least a portion of the guided light - that reaches the opposing end - back into the light guide as return light, such that substantially all the return light impinges on the pair of opposing side surfaces at incident angles (142a; 142b) smaller than a critical incidence angle and transmits through the pair of opposing side surfaces into the ambient as output light of the luminaire module, the output light to propagate in backward directions, characterized in that the redirecting end-face (240; 240a-240d) is further configured to transmit another portion of the guided light - that reaches the opposing end - through the redirecting end-face in the forward direction into the ambient as output light a redirecting end-face (240; 240a-240d) located at the opposing end and configured to reflect at least a portion of the guided light - that reaches the opposing end - back into the light guide as return light, such that substantially all the return light impinges on the pair of opposing side surfaces at incident angles (142a; 142b) smaller than a critical incidence angle and transmits through the pair of opposing side surfaces into the ambient as output light of the luminaire module, the output light to propagate in backward directions, characterized in that the redirecting end-face (240; 240a-240d) is further configured to transmit another portion of the guided light - that reaches the opposing end - through the redirecting end-face in the forward direction into the ambient as output light