Abstract: An arrangement which generates red, green and blue laser radiation comprise a laser radiation source whose first beam (&lgr;l) is split in the infrared wavelength range, wherein the first part of this beam is frequency-doubled and green light (&lgr;G) results and another part is used to generate light of the primary colors red (&lgr;R) and blue (&lgr;B). Another part of the first beam (&lgr;l) is fed to a wavelength converter which generates another beam (&lgr;2, &lgr;4) in the infrared wavelength range which has a greater wavelength than the first beam (&lgr;l), further, the colors red (&lgr;R) and blue (&lgr;B) result from the further beam (&lgr;2, &lgr;4) or from a part thereof by another nonlinear process by sum frequency mixing or by frequency doubling or by sum frequency mixing and frequency doubling.

Abstract: A fiber amplifier is disclosed comprising a signal source (oscillator), an amplifier fiber and a pump laser. The amplifier fiber is arranged between two polarizers and a portion of the beam that is depolarized in the amplifier fiber is coupled out at the amplifier output, returned to the amplifier input, coupled into the amplifier fiber with the radiation from the signal source and amplified again, and another portion, as linearly polarized beam, exits the fiber amplifier as useful beam.

Abstract: An RGB laser radiation source comprising a first laser radiation source whose first beam (1) is divided in the infrared wavelength region, wherein the first part thereof is frequency-doubled and green (G) light results and another part thereof is used to generate light of another primary color. It is wherein a second beam (2) is split in the infrared wavelength region from a second laser radiation source, wherein a first part of the second beam (2) together with a second part of the first beam (1) is supplied to a first sum frequency mixing and red (R) light results, and, further, a second part of the second beam (2) is frequency-doubled. This frequency-doubled beam (3) together with a third part of the first beam (1) is supplied to a second sum frequency mixing and blue (B) light results.