Stigmatically imaging torus mirrors - - flat grating monochromator

摘要

A monochromator for electromagnetic radiation, which, for all wavelengths in the area of the stationary input diaphragm stigmatically images on the stationary discharge orifice plate.it as optically active elements a planar reflection grating with blaze, a rotation ellipsoid mirror or a the rotation ellipsoid mirror optimally approximated torus mirrors and, in the alternative, an additional plane mirror contains,the on the centers of the optically active elements erected as well as in the normal of the meridionally plane in which the axis of rotation of the ellipsoid mirror and the stationary axes of the incident and emergent beam of rays, which the center points of the inlet - and / or discharge orifice plate, and the grating lines of the perpendicular to the plane are meridionally,the stigmatic imaging by means of the compensation of the lighting at the reflection grating is not in parallel with the astigmatism arising for the incident angle τ ≠ τ₀ = arccosine [(ϱ₁/ϱ₂)^1/2] from the torus mirrors produced in this case, astigmatism is achieved and ϱ₂ ϱ₁ the two radii of the torus spie gel indicate,the geometric conditions, the grating equation, as well as the required compensation of the astigmatism a system of coupled nonlinear equations result, the solution to which is in general from the wavelength dependent coordinates of the center points of the active optical elements, as well as the generally also wavelength-dependent angle coordinates of the in these centers erected surface normal supplies,the grating equation mλ 2dcos (φ) = sin (ε) is as follows and in this case m 0 for the order of diffraction, λ for the wavelength, d for the grating constant and φ. + ε for the incidence - and / or remittance angle with respect to the grid normal 18 are,the astigmatism of the grating by the following equation: | r / r | [cos (φ + ε) / cos (φ + ε]² is given, the upper or lower sign in this case for convergent or divergent illumination of the grid, it is true | r | of the distance of the virtual meridional focal point from the centre point of the grating and r of the corresponding distance of the real meridional focal point is,the astigmatism of the torus spie gel by the equations for the meridional fig. 2 / α = 1 / g_w + 1 / b_m with ϱ₂ = α²/b and b / α = cosτ as well as for the sagittal image 2cosτ / ϱ₁ = 1 / g_w + 1 / b_s in this case, g is described and object distances and the image intercepts b_m and b_s Distance of the meridional and sagittal image points on the axis of the bundle of rays from the center point of the torus spie gel indicateand for ε = the blaze angle from the grating equation calculated product mλ falls into the region of the monochromator.