The retardation plates we make from quartz. Their thickness is set for the ordering function wavelength, usually for value λ/4 or λ/2, for perpendicular incidence of light, in order K=2 to 6, in the thickness around of 0.2 mm, for working temperature 22 °C. There is possible to order these plates for another conditions and proportions. The optical axis of the plate is marked on the edge of it with small indentation. The plates fulfil the toleration of phase shift better as λ/100, a deformation of wave plane is better as λ/10 after the passing of light. It is possible to order the plates in the another form as circle, with orientation according to the edge of them. There is possible according to order to coat the planes of plates with antireflection films. These ones are very preciously polished plane parallel plates from very clear materials. Their cirkumference is edged into elliptic form. The plate is situated with the respect of light ray incidence for Brewsters angle ß. So it is ensured, that the plate will work as the linear polarizer and the reflects from the plate sides have any effects. These plates can be affixed or soldered on the front of tubes of gas lasers. The accuracy of planes flats is better as λ/10, the wedging is smaller as 10“. The roughness of optical polished surfaces is smaller as Ra=5 nm. We product these plates from flint glass of type Homosil, Suprasil, etc., in the ordered parameters.