Abstract: It is the case of an interferometric measuring arrangement for superimposing at least two light waves, with a first coupling means for coupling the light waves coming from a light source into a sample arm and into a reference arm, and with a second coupling means for superimposing the light waves coming from the reference arm and the sample arm, which are led to at least one detector. The light waves at least within the reference arm are exclusively led in at least one fiber guide which they do not leave on their path between the coupling means, and with which the sample arm extends on both sides of the first coupling means.

Abstract: The device serves the change of the length of the running path of an electromagnetic wave, and specifically of a light beam between the emitter and receiver. It comprises two oppositely lying reflection means between which the beam is reflected, as well as a means for changing the distance of these reflection means. The reflection means are arranged at an angle &bgr; to one another which lies between 0° and 45° so that the incident beam is thrown to and fro several times between the reflection means, until it is finally congruently thrown back.

Abstract: Systems, methods, and apparatus are provided for deriving the relative position of an eye by tracking a boundary of the eye such as the limbus (i.e., the interface between the white sclera and the colored iris). A technique for tracking the position of the eye of patient comprises directing light to an annular region of the eye between the sclera and the iris and receiving reflected light from that region. The intensity of the reflected light is then measured to determine a relative position of the eye. In some embodiments, the measured region is scanned around the boundary. In other embodiments, a light spot is scanned around a substantially annular trajectory radially outward from the pupil. The signals corresponding to the intensity of the reflected light are then processed and measured to determine the eye's position. A flap of tissue covering the boundary may be automatically detected so as to selectively measure the boundary away from the flap.

Abstract: A functionalized copolymer of the formulaA--B--Z--XwhereA is a block of vinylaromatic monomers of 8 to 20, preferably 8 to 12, carbon atoms,B is a block of alkadiene monomers of 4 to 12, preferably 4 to 8, carbon atoms,Z is a fundamental building block of a compound having sterically hindering groups andX is a functionalized fundamental building block,a process for its preparation, thermoplastic molding materials containing said copolymer, processes for their preparation, the use for the production of moldings and moldings comprising said molding materials.

Abstract: Graft copolymers are prepared by anionic polymerization which comprises reacting polymers (A) having at least one anionic chain end with polymers (B) which contain at least one nitrile group, in the presence of a solvent.

Abstract: A method and apparatus for reducing unwanted pressure changes generated during treatment of a target material in a liquid-filled space with a laser. A pilot pulse is generated to produce a gas bubble in a region of the liquid-filled space before a processing pulse is directed through the region and onto the target material. An impulse spacing between the pilot pulse and the processing pulse is optimized by detecting an oscillation period of the gas bubble. The pilot pulse and processing pulse may be generated by the same or separate laser sources and directed toward the target material by the same or separate conductors, respectively.

Abstract: A method of laser lithotripsy is disclosed that utilizes pulse stretched Q-switched solid state lasers in conjunction with relatively small diameter optical fibers to achieve effective breakup of calculi located within the body, such as kidney and gall stones.

Abstract: In a method for the machining of material using a laser with detection of the material to be machined, laser light is directed at the material via a laser optical system and the light re-emitted by the material is guided to a first detector arrangement which measures the intensity of the light and behind which there is connected an evaluation circuit for controlling the laser power or energy. The energy fed to the material via the laser optical system is measured, and the detector arrangement supplies to the evaluation circuit a display signal which indicates the beginning of the dielectric breakdown. The evaluation circuit reduces the power of the laser and/or interrupts the laser pulse if no display signal has as yet occurred at a predetermined time at which a predetermined energy was fed to the material.

Abstract: In a method and an apparatus for material processing with the aid of a laser the laser light is directed via a laser optical system onto the material and the light reemitted or scattered back by the material is conducted via the laser optical system onto a detector arrangement which is followed by an evaluating circuit for controlling the laser. The amplitude-versus-time profile of the light incident on the detector arrangement is evaluated and used to control the laser and/or an optical switch arranged in the output beam path of the laser.