FIGS. 2A-2H illustrate a multi-pass system 100 equipped with a reflector assembly 202, in accordance with one or more embodiment of the present disclosure. The reflector assembly 202 of this embodiment may provide for radiances that are much closer to the blackbody limit. The collection of multiple passes through a plasma allows for the optimization of the gas pressure as if the plasma was much larger. As a result, the absorption/emissivity of the desired broadband output wavelengths in the plasma per each pass can be reduced. In the case where a similar geometry is used for the pumping illumination, the absorption of pumping illumination can be reduced as well, allowing for a lower gas pressure. The operation of system 100 at lower gas pressure aids in reducing “gas wiggle,” which result from density and temperature gradients leading to variations in the refractive index.

In addition, light emitted by the plasma 106 of the reflector assembly 202 at angles that do not take it to an output port are always focused back to (or proximate to) the plasma(s). As a result, light that would normally be lost is partially used to pump the plasma(s). Such a configuration results in an improvement of efficiency of the system 100 relative to single-pass systems and allows for a less powerful pump source 104 to achieve a given broadband radiance.

FIGS. 2A-2B illustrate cross-sectional views of the reflector assembly 202 of system 100, in accordance with one or more embodiments of the present disclosure. It is noted that FIG. 2A represents a cross-section that is perpendicular with respect to the cross-section of FIG. 2B.