Figure 14
Diffraction efficiency of a blazed 600 lines mm−1 grating measured in standard PGM operation mode (c = 2.25). Colour code as in Fig. 13. Using an Fe (750 nm) filter (red curve) only the second order can be suppressed; the HiOS (operated with AlF3-coated mirrors at 2.5°) (green curve) suppresses all higher orders. |