Abstract: A method for intracavity frequency conversion includes end-pumping a solid-state gain medium in a laser resonator with a pump laser beam to generate an intracavity laser beam circulating in the laser resonator, and frequency-converting a portion of the intracavity laser beam in a nonlinear crystal, located in the laser resonator, to generate a frequency-converted laser beam. The method controls the output power and at least one output beam parameter of the frequency-converted laser beam by adjusting (a) the pump power and (b) a resonator loss imposed on the intracavity laser beam. Taking advantage of both the pump laser beam and the intracavity laser beam contributing to thermal lensing in the gain medium, this control scheme is capable of controlling the output power and the output beam parameter(s) independently of each other.

Abstract: This disclosure provides methods and apparatuses which advantageously stabilize beam parameters and elongate crystal lifetime. In one aspect, a UV laser apparatus includes a non-linear crystal, a laser source, a beam-crystal displacer, a beam parameter monitor, and a laser control unit. The laser source directs a source beam to the non-linear crystal to produce a UV beam and the beam-crystal displacer shifts the non-linear crystal relative to the source beam at a plurality of shift speeds. The beam parameter monitor measures the UV beam and outputs a measurement of a beam parameter. The laser control unit: receives the measurement; determines, based on the measurement, an adjustment in shift speed that steers the beam parameter toward a target value; and outputs the adjustment to the beam-crystal displacer.

Abstract: In an optical arrangement for pumping solid-state lasers, there is the object of producing an intensity distribution across the beam cross section of the pump radiation with a rectangular intensity profile, which intensity distribution is homogeneous at least in a region corresponding to the Rayleigh range in the direction of the beam propagation without the beam quality being substantially impaired by the homogenization. The pump arrangement contains a rod-shaped homogenizer (1) with two opposed, polished end faces (2,3), planar side limit faces (4), which are arranged parallel to the optical axis and with a cross-sectional area at right angles to the optical axis, which forms a regular polygon, with the regular polygon being restricted to those number of sides which permit a plurality of polygons to be positioned against one another on a surface in such a way that they fill the space.

Abstract: A laser system, which is used in material processing to produce a radiation line of small width and uniform high intensity in the longitudinal direction, produces radiation that has different mode numbers M2 perpendicular to the propagation direction.

Abstract: A laser for generating pulsed laser radiation. An element is arranged in the resonator to generate laser radiation having the first wavelength by frequency conversion of the primary radiation. The resonator is switchable into a first state in which it is open to the primary radiation, and a second state in which it is closed to the primary radiation, and is open to laser radiation of the first wavelength in both states. A control unit switches the resonator from the first to the second state so that the primary radiation begins to oscillate and the pulse generation by frequency conversion begins, switches the resonator from the second to the first state, whereby primary radiation is coupled out from the resonator. It is possible to set the duration between both steps and/or the coupling-out behavior of the resonator to adjust the pulse duration via the control unit.

Abstract: A laser for generating pulsed laser radiation is provided. The laser includes a resonator, a laser-active medium arranged in the resonator, and an acousto-optic modulator arranged in the resonator. The modulator can be put in a first and a second state so as to set the resonator quality, the resonator quality being lower in the first state than in the second state, and comprising a control unit for controlling the modulator. The control unit effects phase-locked coupling of a high-frequency signal to be applied to the modulator in one of said two states, in order to generate a predetermined sound field in the modulator, and a switching signal designed to switch the modulator periodically between the two states.

Abstract: A laser for generating pulsed laser radiation. An element is arranged in the resonator to generate laser radiation having the first wavelength by frequency conversion of the primary radiation. The resonator is switchable into a first state in which it is open to the primary radiation, and a second state in which it is closed to the primary radiation, and is open to laser radiation of the first wavelength in both states. A control unit switches the resonator from the first to the second state so that the primary radiation begins to oscillate and the pulse generation by frequency conversion begins, switches the resonator from the second to the first state, whereby primary radiation is coupled out from the resonator. It is possible to set the duration between both steps and/or the coupling-out behavior of the resonator to adjust the pulse duration via the control unit.

Abstract: The object of a pulsed laser arrangement and a method for adjusting the pulse length of laser pulses is to change the pulse length over a wide range substantially independent from the laser output power, in particular to counteract a reduction in output and to prevent a negative change in the beam parameters when lengthening the pulse by means of varying the oscillator output. A multistage laser amplifier in which an amplifying medium with a small-signal amplification of more than 10 is provided in every stage (17-22) is arranged downstream of a diode-pumped Q-switched solid state laser oscillator with variable oscillator output for supplying oscillator pulses. The total small-signal amplification brought about by all of the amplifying media is greater than 1000. The pulsed laser arrangement and the method can be used for industrial and medical purposes requiring pulse lengths in the range of several hundred ns to several ?s at pulse repetition rates between 10 kHz and 200 kHz.

Abstract: In a laser arrangement and a method for generating a multimode operation with intracavity frequency doubling, the object of the invention is to eliminate fluctuations in output caused by the nonlinear coupling between the longitudinal modes due to sum frequency generation in a simple laser construction which has increased thermal and mechanical stability. Two multimode spectral regions are situated in the edge areas of the spectral gain region of a disk-shaped gain medium within which longitudinal modes have no gain advantage among one another for spatial hole burning, and in which oscillation of one of the two multimode spectral regions is prohibited.

Abstract: The object of a pulsed laser arrangement and a method for adjusting the pulse length of laser pulses is to change the pulse length over a wide range substantially independent from the laser output power, in particular to counteract a reduction in output and to prevent a negative change in the beam parameters when lengthening the pulse by means of varying the oscillator output. A multistage laser amplifier in which an amplifying medium with a small-signal amplification of more than 10 is provided in every stage (17-22) is arranged downstream of a diode-pumped Q-switched solid state laser oscillator with variable oscillator output for supplying oscillator pulses. The total small-signal amplification brought about by all of the amplifying media is greater than 1000. The pulsed laser arrangement and the method can be used for industrial and medical purposes requiring pulse lengths in the range of several hundred ns to several ?s at pulse repetition rates between 10 kHz and 200 kHz.

Abstract: The object in an arrangement for pumping an anisotropic laser crystal is to reduce the influence of the destruction limit of the laser crystal on increased pump power density and, in this connection, to achieve improved beam quality and increased efficiency of a diode-pumped solid state laser. At the same time, the pump volume and cross-sectional area are to be kept as small as possible along a length of the crystal corresponding at least approximately to the absorption length. The arrangement operates with an asymmetric pump beam whose pump beam cross section has different dimensions perpendicular to one another and with a laser beam cross section which is adapted to this asymmetry. That axis of the crystallographic axes of the anisotropic laser crystal in whose direction the highest value of the crystal breaking limit exists is oriented along the greatest temperature gradient in the direction of the smaller dimension of the pump beam cross section.

Abstract: The invention relates to an arrangement and a method for generating ultrashort laser pulses. The aim of the invention is to avoid the deterioration of the beam quality caused by the plurality of required revolutions, the accompanying loss of revolutions, and pulse broadening in regenerative amplifiers by means of a simpler and more cost-effective laser installation, and to provide ultrashort laser pulses with pulse repeat rates in an extended kHz range. In an installation consisting of a solid-state laser oscillator, a multi-stage laser amplifier which is arranged downstream therefrom and is used to increase the energy of pulses, and at least one switching element for selecting pulses from a pulse train provided by the solid-state laser oscillator, a small-signal gain higher than 10 is provided in an amplifying laser crystal in each amplification stage, the total small-signal gain produced by all amplifying laser crystals amounting to more than 100.

Abstract: Disclosed is an optical array for generating a broadband spectrum. The aim of the invention is to reduce the technical complexity of said optical array while keeping the source of laser radiation compact and adjusting in a simple manner the wavelength range of the broadband spectrum to the sensitivity range of conventional semiconductor detectors. Said aim is achieved by coupling in an optically adapted manner a passively mode-coupled solid body laser which supplies picosecond impulses having an initial wavelength that lies within the infrared range to a photonic fiber. A radiation performance interval of the broadband spectrum, which is maintained at an essentially steady intensity, is set within a wavelength range of 700 nm to 1000 nm below the initial wavelength by adjusting the dispersion of said photonic fiber to the initial wavelength.

Abstract: A diode laser arrangement is disclosed wherein a radiation source is designed which can be scaled with respect to power such that different types of cooling can be applied and the configuration of the radiation field is suitable for adapting to different tasks in a simple manner. For this purpose, every diode laser is connected to a thermal contact surface of a separate, heat-spreading carrier which is fastened to a cooling surface of a common cooling element so as to be electrically insulated. The carriers are arranged adjacently in such a way that the line-shaped emission regions of the diode lasers are adjacent in series and the p-n junction planes extend parallel to the thermal contact surfaces. The diode laser arrangement is particularly suitable as a pump light source.

Abstract: A diode-pumped laser is disclosed with internal frequency doubling to prevent interfering power fluctuations in the laser radiation generated by the non-linear crystal at the start of the power adjustment in a simple and, therefore, inexpensive construction without power-reducing elements in the cavity or thermal effects having a negative impact on the laser behavior. The laser contains, as laser-active medium, a solid-state laser crystal with a temperature gradient directed substantially parallel to the cavity axis. The conversion of laser radiation of a fundamental laser wavelength into laser radiation of another wavelength is carried out by a non-linear optical crystal with a lower non-linear conversion efficiency than that required for achieving maximum power of the converted laser radiation. The laser can be used particularly for medical purposes, e.g., in the field of ophthalmology for coagulation of the retina as well as in the field of dermatology.

Abstract: In a diode-pumped laser amplifier the inventive object is to increase the tolerance of the amplifier arrangement relative to variations of the input parameters significantly, so that fine-tuning is no longer necessary for guaranteeing the stability of the amplifier. Into a laser-active solid-state medium where a thermal lens of a strength which is different in orthogonal planes is generated in consequence of the irradiated pump radiation, a laser beam to be amplified is directed into the laser-active solid-state medium while being focused in the plane with a strong thermal lens, wherein a beam waist that is being generated lies in the area of the thermal lens. The laser amplifier can be used for amplifying the radiation of an oscillator.

Abstract: A diode laser arrangement is disclosed wherein a radiation source is designed which can be scaled with respect to power such that different types of cooling can be applied and the configuration of the radiation field is suitable for adapting to different tasks in a simple manner. For this purpose, every diode laser is connected to a thermal contact surface of a separate, heat-spreading carrier which is fastened to a cooling surface of a common cooling element so as to be electrically insulated. The carriers are arranged adjacently in such a way that the line-shaped emission regions of the diode lasers are adjacent in series and the p-n junction planes extend parallel to the thermal contact surfaces. The diode laser arrangement is particularly suitable as a pump light source.

Abstract: The object in an arrangement for pumping an anisotropic laser crystal is to reduce the influence of the destruction limit of the laser crystal on increased pump power density and, in this connection, to achieve improved beam quality and increased efficiency of a diode-pumped solid state laser. At the same time, the pump volume and cross-sectional area are to be kept as small as possible along a length of the crystal corresponding at least approximately to the absorption length. The arrangement operates with an asymmetric pump beam whose pump beam cross section has different dimensions perpendicular to one another and with a laser beam cross section which is adapted to this asymmetry. That axis of the crystallographic axes of the anisotropic laser crystal in whose direction the highest value of the crystal breaking limit exists is oriented along the greatest temperature gradient in the direction of the smaller dimension of the pump beam cross section.

Abstract: In a diode-pumped laser amplifier the inventive object is to increase the tolerance of the amplifier arrangement relative to variations of the input parameters significantly, so that fine-tuning is no longer necessary for guaranteeing the stability of the amplifier. Into a laser-active solid-state medium where a thermal lens of a strength which is different in orthogonal planes is generated in consequence of the irradiated pump radiation, a laser beam to be amplified is directed into the laser-active solid-state medium while being focused in the plane with a strong thermal lens, wherein a beam waist that is being generated lies in the area of the thermal lens. The laser amplifier can be used for amplifying the radiation of an oscillator.

Abstract: The invention relates to a diode-pumped solid-state laser (DSSL) comprises a pumping light source having a diode stack. The inventive laser also comprises a laser rod and a pumping cavity, whereby the pumping light source accommodated in a separate housing can be exchanged as a pumping module with simple handles. As a result, the pumping light source is protected from electrostatic discharge of the diodes, mechanical stress and from contamination. Given that it is possible to accommodate alternative pumping light sources of varying pumping capacities in the pumping module, the user can exchange the pumping module when the pumping module is worn as well as when additional power is required.