Abstract: A radiation source that provides high order harmonic radiation (HHG radiation) in an UV or XUV wavelength range comprising a resonant cavity that guides laser light pulses that includes at least two cavity mirrors, a first non-linear medium that provides the HHG radiation by harmonic generation based on an interaction of the laser light pulses with the first non-linear medium, wherein the first non-linear medium is arranged in the resonant cavity in an environment of reduced pressure, and a second non-linear medium arranged in the resonant cavity and adapted for at least one of amplifying the laser light pulses and phase locking longitudinal modes of the laser light pulses in the resonant cavity.

Abstract: Method and device for the generation of a comb of stabilized frequency lines and/or a train of ultrashort laser pulses for stabilization of the position of the carrier wave with respect to the amplitude envelope of few cycles laser pulses. Interference between spectral components generated by means of difference frequency generation and self phase modulation in one and the same non-linear crystal (4) allows detecting and stabilizing the temporal evolution of the carrier-envelope offset (CEO) phase. The described technique improves dramatically the accuracy of the stabilization and has very small insertion losses.

Abstract: Method and device for the generation of a comb of stabilized frequency lines and/or a train of ultrashort laser pulses for stabilization of the position of the carrier wave with respect to the amplitude envelope of few cycles laser pulses. Interference between spectral components generated by means of difference frequency generation and self phase modulation in one and the same non-linear crystal (4) allows detecting and stabilizing the temporal evolution of the carrier-envelope offset (CEO) phase. The described technique improves dramatically the accuracy of the stabilization and has very small insertion losses.

Abstract: A short pulse laser arrangement (11) with, preferably, passive mode-locking, comprising a resonator (12) containing a laser crystal (14) and several mirrors (M1-M7; OC), one of which forms a pump beam coupling-in mirror (M1) and one of which forms a laser beam out-coupling mirror (OC), and a multiple reflexion telescope (18) enlarging the resonator length, the resonator (12) in operation having a positive averaged dispersion over a wavelength range concerned; the adjustment of the positive averaged dispersion of the resonator (12) is effected by means of the mirrors (M1-M7, OC) of the resonator (12), at least a few of which are designed as dispersive mirrors.

Abstract: A dispersive multilayer mirror (1) comprising several individual layers (2, 3) applied to a carrier substrate (4) and adjoining each other via parallel, plane surfaces having different optical constants and different thicknesses, wherein a wedge-shaped glass platelet (5) is fastened to the outermost individual layer (2) facing away from the carrier substrate (4) by optical contact.

Abstract: A dental laser arrangement switchable between different modes of operation, the arrangement including a laser device operable as a laser oscillator and as a laser amplifier. The laser device includes a laser resonator having a pump unit and an active modelocker as well as an optic loss element that introduces selective losses in the resonator. The laser arrangement further includes a laser beam-out-coupling unit. The modelocker is connected to a control circuit for switching between a CW-mode of operation for coagulating soft tissue, in which the modelocker is switched off, and two short-pulse modes of operation in which high frequency signals of equal frequencies, but different powers are applied by the control circuit to the modelocker so as to generate laser pulses of a pre-determined duration.

Abstract: A cooling device for an optical amplifier or oscillator has Peltier elements enclosed in a housing with an optical crystal and extract heat from the optical crystal. The housing is sealed and can contain a desiccant for removing moisture and preventing particle deposition. Alternately, the housing can be evacuated with a vacuum to maintain a clean operating environment. The housing holds a Brewster window at a Brewster angle with an inident laser beam to permit passage of the laser beam. The housing also can be arranged on a platform providing liquid cooling.

Abstract: A cooling device for an optical amplifier or oscillator has Peltier elements enclosed in a housing with an optical crystal and extract heat from the optical crystal. The housing is sealed and can contain a desiccant for removing moisture and preventing particle deposition. Alternately, the housing can be evacuated with a vacuum to maintain a clean operating environment. The housing holds a Brewster window at a Brewster angle with an inident laser beam to permit passage of the laser beam. The housing also can be arranged on a platform providing liquid cooling.

Abstract: A multilayer mirror (1), in particular a multilayer dispersive mirror, comprising several individual layers (2, 3) of different properities applied to a substrate (4; 14) and following each other via parallel, plane interfaces (6), and a plane front face (5; 5?) on the side of beam impact which is inclined relative to the interfaces (6) between the individual layers (2, 3).

Abstract: A Laser arrangement (1) comprising a pump unit (2) containing a pumped laser crystal (3), and means, such as a saturable absorber (15), for passive mode-locking, wherein two separate, alternatively switchable resonator arms (11, 12) are provided, one resonator arm (11) of which, which is active in a pulse forming phase (21), comprises the saturable absorber (15), whereas the other resonator arm (12), which is active in an amplifying phase (22), is free from components that introduce losses.

Abstract: A dental laser arrangement switchable between different modes of operation, comprising a laser device (1) operable as a laser oscillator and as a laser amplifier, comprising a laser resonator (8) which includes a pump unit (12) and an active modelocker (16) as well as an optic loss element (17′) introducing selective losses in the resonator (8), and further comprising a laser beam-out-coupling unit (21), wherein the modelocker (16) is connected to a control circuit (27) for switching between a CW-mode of operation (C) for coagulating soft tissue, in which the modelocker (16) is switched off, and two short-pulse modes of operation (A, S) in which high frequency signals of equal frequencies, but different powers (P1, P2) are applied by the control circuit (27) to the modelocker (16) so as to generate laser pulses of a pre-determined duration, one of the two short-pulse modes of operation (A) being provided for ablation of hard tooth tissue, and the other short-pulse mode of operation (S), in which the las

Abstract: A dispersive multilayer mirror (1) comprising several individual layers (2, 3) applied to a carrier substrate (4) and adjoining each other via parallel, plane surfaces having different optical constants and different thicknesses, wherein a wedge-shaped glass platelet (5) is fastened to the outermost individual layer (2) facing away from the carrier substrate (4) by optical contact.

Abstract: A cooling device for an optical amplifier or oscillator has Peltier elements enclosed in a housing with an optical crystal and extract heat from the optical crystal. The housing is sealed and can contain a desiccant for removing moisture and preventing particle deposition. Alternately, the housing can be evacuated with a vacuum to maintain a clean operating environment. The housing holds a Brewster window at a Brewster angle with an incident laser beam to permit passage of the laser beam. The housing also can be arranged on a platform providing liquid cooling.

Abstract: A passively mode-locked short pulse laser arrangement (1) comprising a laser resonator to which a pump beam (3) is supplied, a laser crystal (4), in particular a titanium-sapphire-(Ti:S-) laser crystal, and laser mirrors (M1 to M7), the laser crystal (4), which is subjected to a thermal load on account of the beam focussing, being mounted on a cooling body (10) provided for the removal of heat, which cooling body includes a bore (13) for the passage of the laser beam (3; 8), and on which a, particularly platelet-shaped, crystal mount (11) of a material with good heat conducting properties, preferably of copper, is provided for an improved removal of heat, the laser crystal (4) being held in an opening (14) of this crystal mount (11) by lateral abutment on oppositely arranged walls (15, 16) of the opening (14) of the crystal mount (11), the opening (14) in the crystal mount (11) being in alignment with the bore (13) in the cooling body (10).

Abstract: In a passively mode-locked short pulse laser arrangement including a laser resonator to which a pump beam is supplied, a titanium-sapphire (Ti:S) laser crystal, an optical Kerr element formed by the laser crystal itself, and an aperture restricting the resonator laser beam, the aperture has an arcuate or polygonal shape for adaptation to the beam cross-section.

Abstract: Dispersive dielectric mirror exhibiting a monotonic, more particularly nearly linear group delay versus frequency function over a wide frequency range within the high reflectivity band of the mirror, which group delay is introduced on electromagnetic wavepackets, more particularly, on light pulses, when the electromagnetic wave is reflected on the mirror. The dispersive dielectric mirror can be well applied for dispersion control in electromagnetic impulse technique from microwave frequencies to X-rays, more particularly, in ultrashort-pulse-laser technique and its applications. One of the concrete applications of the dispersive dielectric mirrors is to solid-state-laser intracavity dispersion control of femtosecond pulse solid-state-laser oscillators instead of using of prism pairs. The laser built in this way is more compact, reliable and user friendly than its prism-pair-dispersion controlled predecessors.