Profiling the arc channel of a cascaded arc into an hourglass-like shape results in an extremely high light output intensity (3.5 * 1012 Wm-2 m-1 sr-1 in the near-IR) at an input power of 2.2 kW, a good stability (better than 5 * 10-4) and a small solid angle of the emitted light beam (W = 0.015 sr). These optical properties are advantageous for spectroscopic applications that require a high light intensity over a broad wavelength range in a small solid angle. The abs. light output is measured and is compared with a fast and flexible modeling scheme. These simulations are used to verify the arc performance and to guide arc design. The calcd. emitted radiance at moderate arc input power agrees with the expts. within 30% for moderate input power.