NI-CU in-field and out-of-field illumination. Left: reconstructed NI-CU EQM illumination in the focal plane using a test system without the full NISP. The fluence drops quickly outside the nominal in-field (black line) until it is close to zero 25 mm further out (red line). The overall light emitted to outside the nominal field, when integrated out to the dashed line, is substantially below the requirement of 10% of the total in-field light. Right: closeup on the radial sharp transition in relative flux density at the edge of the nominal NI-CU illuminated field, here independently measured for the NI-CU VM – the approximate edge of the nominal NISP FPA in-field is marked by the vertical line. This indicates a functioning baffling approach and creates a very low amount of straylight inside the NISP cavity from light falling outside the target FPA area.