Bent Glass Optics

We describe how a glass strip may be bent to match any curve of large radius of curvature, to a high de-gree of accuracy, so that it may be used as a glancing incidence X-ray or extreme ultraviolet optical element. The desired match is obtained by applying a suitable combination of end couples and adjusting the cross-sectional moment of inertia along the length of the strip by varying its breadth. Two applications are described; a parabolic reflector for use as a laboratory X-ray collimator for testing mechanical collimators to be used in space instruments, and an elliptical reflector for point-to-point focussing. The latter device has been used for testing gratings in the X-ray and extreme ultraviolet (euv) regions and for concentrating radiation on to the entrance slit of a spectrometer, with a resultant gain in speed and resolution. We suggest that the technique may have other laboratory and space applications, which are briefly described.