Abstract: Systems for inspecting a surface of an optical wave originating from an optical device are provided. The optical device includes an exit pupil, and the inspection system includes an optical measuring head and a computer for processing the images from said optical measuring head. The optical measuring head includes a density gradient filter, the density varying periodically in the two directions in space, a matrix frame having at least four identical lenses of square shape of the same focal length and being arranged symmetrically, and a photodetector array, each of the four lenses forming an image of the pupil in the plane of this array. The image processing computer includes computing means for computing the partial derivatives ? ? ? x ? ( x , y ) and ? ? ? y ? ( x , y ) of the wave surface ?(x, y) in the plane of the exit pupil.

Abstract: The detection device comprises a cold finger which performs the thermal connection between a detector and a cooling system. The cold finger comprises at least one side wall at least partially formed by an area made from the amorphous metal alloy. Advantageously, the whole of the cold finger is made from the amorphous metal alloy.