Abstract: Device for centerpoint wavelength adjustment of emitted radiation of an LED unit having at least one interference filter arranged downstream in the optical axis of the LED unit. The LED unit and the interference filter are connected to at least one temperature regulating unit, and the temperature regulating unit is connected to at least one temperature acquisition unit. The temperature acquisition unit acquires the temperature of the LED unit as well as a temperature of the interference filter.

Abstract: The present invention pertains to a refractometer with a refractometer prism, on the measuring surface of which a sample to be analyzed can be placed, which can be illuminated by a light source in such an angle range that the critical angle of the total reflection is also contained in it, and with a receiver, on which the reflected radiation falls. The light source comprises a plurality of discrete light sources, which can be activated individually or together, and their radiation can be sent in one point to the refractometer in a bundled form.

Abstract: A refractometer with a measuring prism on whose measuring surface a sample to be tested can be mounted, which sample can be illuminated by a light beam emitted by a source of light under a range of angles that includes a critical angle for total reflection, and with a reciever for recieving the reflected light. An optical device that decomposes the reflected light into a color spectrum that is mounted in the path of the reflected light between the measuring surface and the reciever.

Abstract: The invention concerns a refractometer with a measuring prism on whose measuring surface a sample to be tested can be mounted, which sample can be illuminated by a light beam emitted by a source of light under a range of angles that includes the critical angle for total reflection, and with a receiver for receiving the reflected light, in which an optical device that decomposes the reflected light into a color spectrum is mounted in the path of the reflected light between the measuring surface and the receiver.

Abstract: A method of growing KTa.sub.x Nb.sub.1-x O.sub.3 by pulsed laser evaporation. In order to compensate for the volatile K, two targets are prepared, one of sintered oxide powder having K, Ta, and Nb in amounts stoichiometric to KTa.sub.x Nb.sub.1-x O.sub.3 and the other of melt-grown KNO.sub.3. The method can also be used to form other complex materials having volatile components using a variety of sputtering growth techniques. The two targets are mounted on a rotating target holder and are alternately ablated by the laser beam. The KNO.sub.3 provides excess K, thus allowing the growth of a stoichiometric film. The method can be applied to many complex materials for which some of the components are volatile.