Abstract: Operating an optical frequency comb assembly includes operating an optical frequency comb source to generate laser light constituting an optical frequency comb and introducing the laser light into a common light path and seeding at least one branch light path by the laser light from the common light path, the branch light path comprising at least one optical element. For the branch light path, a phase difference of a first frequency mode ?1 of the optical frequency comb is determined between laser light coupled out at a reference point within the frequency comb assembly upstream of the at least one optical element and laser light coupled out at a measurement point provided in the branch light path downstream of the at least one optical element. Phase correction for the laser light from the branch light path is based on a deviation of the determined phase difference from a target value.

Abstract: The invention relates to a system (1) for generating a (high-frequency) beat signal. The system has a first light source (3) with a multimode spectrum, a second light source (4) and a coupler and filter arrangement (5) with a first port (6) for coupling in light from the first light source (3), and a second port (7) for coupling in light from the second light source (4). Furthermore, a detector (11) is provided to which light of both light sources (3, 4) can be supplied. The coupler and filter arrangement (5) has a spectral filter (20, 28) for filtering out one or several modes from the spectrum of the first light source (3), and a first fiber-optical coupler (17, 23, 26) for coupling the light of the second light source (4) and the not yet filtered or the already filtered light of the first light source (3). The coupler and filter arrangement (5) is configured to be merely fiber-optical.

Abstract: A laser (12, 18) with a laser resonator (13), the laser resonator (13) having a non-linear optical loop mirror (1, 1?), NOLM, which is adapted to guide counter-propagating portions of laser pulses, and to bring the counter-propagating portions of laser pulses into interference with each other at an exit point (4) of the NOLM (1, 1?). The non-linear optical loop mirror (1, 1?) has a non-reciprocal optical element (7, 7?).

Abstract: The invention relates to an optical arrangement (20) and to a method of examining or processing an object (46). Here, a first laser pulse with a first central wavelength and a second laser pulse with a second central wavelength different from the first central wavelength are generated. Both pulses are superimposed in or on the object (46) such that multi-photon absorption takes place there with the involvement of at least one photon of the first laser pulse and at least one photon of the second laser pulse.

Abstract: The invention relates to an optical assembly (1) comprising a pulsed light source (2) for generating primary light pulses (4), a pulse splitter (5) for splitting said primary light pulses (4) into first and second secondary light pulses (7), and a delay element (8) for delaying said second secondary light pulses (7) relative to said first secondary light pulses (6), where the pulse repetition rate of said pulsed light source (2) is variable in order to change a temporal delay between different secondary light pulses (6,7) The invention is characterized in that said optical assembly (1) comprises a thermal insulation (12), a temperature stabilizer (16) or a temperature compensator (13) for said delay element (8) and/or a control circuit (27) for determining and controlling a drift of said pulse repetition rate.

Abstract: A device for generating or receiving electromagnetic radiation in a frequency range from 10 GHz to 100 THz is provided. The device includes a housing and a wave guide fiber leading into the housing. The wave guide fiber is adapted for guiding pulsed laser light with a first central wavelength. Within the housing, a terahertz converter is provided for generating or receiving the electromagnetic radiation in the terahertz range. The device also includes a frequency converter for converting the light exiting from the wave guide fiber to a second central wavelength being arranged between the end of the wave guide fiber and the terahertz converter in such a way that the terahertz converter is impinged by the frequency converted light.

Abstract: A method for generating two delayed pulses, in particular in terahertz spectroscopy and/or in pump-probe experiments, with the following method steps: generating a pulsed beam using a beam source, in particular a pulsed laser; dividing the pulsed beam, where a first partial beam contains a first pulse and a second partial beam contains a second pulse; directing the two pulses onto a respective target area, the first pulse directly reaching a first target area and the second pulse reaches a second target area after covering a delay path, and the two target areas may coincide; using the two pulses, in particular for a measuring method, where a time delay of the two pulses in the respective target area is adjustable by a pulse repetition rate of the pulsed beam.

Abstract: A device for generating or receiving electromagnetic radiation in a frequency range from 10 GHz to 100 THz is provided. The device includes a housing and a wave guide fiber leading into the housing. The wave guide fiber is adapted for guiding pulsed laser light with a first central wavelength. Within the housing, a terahertz converter is provided for generating or receiving the electromagnetic radiation in the terahertz range. The device also includes a frequency converter for converting the light exiting from the wave guide fiber to a second central wavelength being arranged between the end of the wave guide fiber and the terahertz converter in such a way that the terahertz converter is impinged by the frequency converted light.

Abstract: The invention concerns a laser system with a frequency comb generator for generating a comb of optical frequencies having an offset frequency and a plurality of equidistant modes. The laser system further preferably includes at least one stabilizer for stabilizing the frequency comb onto a certain offset frequency and/or onto a certain mode spacing. The laser system further includes an optical amplifier for amplifying the frequency comb coupled out of the frequency comb generator, the amplification factor of this amplifier being variable; and the amplifier is followed by a Raman medium for generating a Raman shift of the frequency comb.

Abstract: A description is given of an optical structure (100), in particular for determining and stabilizing the relative phase of short pulses, which contains a broadening device (6) for broadening the frequency spectrum of pulses of electromagnetic radiation, and a frequency multiplier device (8) for multiplying at least one frequency component of the pulses, wherein a focusing lens optic (7) is arranged between the broadening device and the frequency multiplier device, which focusing lens optic can be used to focus the pulses into the frequency multiplier device (8). Uses of this optical structure are also described.