An illumination device comprising: a plurality of light-emitting elements (LEEs); a light guide extending in a forward direction from a first end of the light guide to a second end of the light guide, the light guide being positioned to receive at the first end light emitted by the LEEs and configured to guide the received light to the second end via total internal reflection; and an optical extractor optically coupled to the light guide (130, 230) at the second end to receive the guided light, the optical extractor (140, 240) being formed from a transparent, solid material and comprising: a redirecting surface acting as a beam splitter configured to transmit a predetermined portion of incident light in a forward output angular range (145'"), while reflecting the remaining light in first and second backward angular ranges (145', 145"), a first output surface having a curvilinear profile in a cross-section that includes the forward direction, the first output surface arranged to transmit, to the ambient environment in a first output backward angular range, light reflected by the redirecting surface in the first backward angular range, and a second output surface having a curvilinear profile in a cross-section that includes the forward direction, the second output surface arranged to transmit, to the ambient environment in a second output backward angular range (145"), light reflected by the redirecting surface in the second backward angular range (145"), characterized in that the illumination device is configured to output light having a far-field light intensity profile with (i) a forward output lobe in the forward angular range and (ii) first and second backward output lobes (145a, 145b) in the first and second output backward angular ranges (145', 145"), respectively, and wherein a ratio between a peak intensity of any of the lobes (145a, 145b, 145c) and a minimum intensity between two adjacent ones of the lobes (145a, 145c) of the far-field light intensity profile exceeds 5 to 1. a plurality of light-emitting elements (LEEs); a light guide extending in a forward direction from a first end of the light guide to a second end of the light guide, the light guide being positioned to receive at the first end light emitted by the LEEs and configured to guide the received light to the second end via total internal reflection; and an optical extractor optically coupled to the light guide (130, 230) at the second end to receive the guided light, the optical extractor (140, 240) being formed from a transparent, solid material and comprising: a redirecting surface acting as a beam splitter configured to transmit a predetermined portion of incident light in a forward output angular range (145'"), while reflecting the remaining light in first and second backward angular ranges (145', 145"), a first output surface having a curvilinear profile in a cross-section that includes the forward direction, the first output surface arranged to transmit, to the ambient environment in a first output backward angular range, light reflected by the redirecting surface in the first backward angular range, and a second output surface having a curvilinear profile in a cross-section that includes the forward direction, the second output surface arranged to transmit, to the ambient environment in a second output backward angular range (145"), light reflected by the redirecting surface in the second backward angular range (145"), a redirecting surface acting as a beam splitter configured to transmit a predetermined portion of incident light in a forward output angular range (145'"), while reflecting the remaining light in first and second backward angular ranges (145', 145"), a first output surface having a curvilinear profile in a cross-section that includes the forward direction, the first output surface arranged to transmit, to the ambient environment in a first output backward angular range, light reflected by the redirecting surface in the first backward angular range, and a second output surface having a curvilinear profile in a cross-section that includes the forward direction, the second output surface arranged to transmit, to the ambient environment in a second output backward angular range (145"), light reflected by the redirecting surface in the second backward angular range (145"), characterized in that the illumination device is configured to output light having a far-field light intensity profile with (i) a forward output lobe in the forward angular range and (ii) first and second backward output lobes (145a, 145b) in the first and second output backward angular ranges (145', 145"), respectively, and wherein a ratio between a peak intensity of any of the lobes (145a, 145b, 145c) and a minimum intensity between two adjacent ones of the lobes (145a, 145c) of the far-field light intensity profile exceeds 5 to 1.