A passively, Q-switched laser is described. The laser may operate at an eye-safe lasing wavelength of 1.34 microns and use a gain element of Nd:YVO.sub.4 and a saturable absorber element of V:YAG with a space separating the gain element and saturable absorber element. The Q-switched laser is pumped by a grating stabilized laser diode. The laser may be used in laser ranging applications.

The present invention provides a blue laser transmitter operating at the H-beta Fraunhofer line at 486.13 nm wavelength. The subject blue laser is based on pulsed lasing action in thulium doped into lutetium sesquioxide (Tm:Lu.sub.2O.sub.3). The laser wavelength is restricted by volume

Bragg grating to the vicinity of 1944 nm wavelength. The laser is operated with a q-switch to generate high-energy pulses within the nanosecond regime. The output at the 1944 nm wavelength is then frequency quadrupled in a single pass through non-linear crystals to a wavelength near the center of the H-beta Fraunhofer line. The operation at the 1944 nm wavelength in Tm:Lu.sub.2O.sub.3 is very efficient because this wavelength is located on a shoulder of a substantially broad emission peak at 1945 nm. In addition, at the 1944 nm wavelength, Tm:Lu.sub.2O.sub.3 has only a modest saturation fluence of about 15 J/cm.sup.2, which allows for efficient energy extraction.

A light source apparatus (200) includes a gas discharge stage (210) and a metal fluoride trap (300). The gas discharge stage includes an optical amplifier (206) and a set of optical elements (250, 260). The optical amplifier includes a chamber (211) configured to hold a gas discharge medium (213), the gas discharge medium outputting a light beam. The set of optical elements is configured to form an optical resonator around the optical amplifier. The metal fluoride trap is configured to trap metal fluoride dust generated from the gas discharge stage. The metal fluoride trap includes an electrostatic precipitator (320) and a packed-bed filter (400, 402, 404) disposed around the electrostatic precipitator. The packed-bed filter includes a plurality of beads configured (406, 408) to absorb metal fluoride dust (208).

An apparatus may include a diode-pumped solid-state laser oscillator configured to output a pulsed laser beam, a modulator configured to modify an energy and a temporal profile of the pulsed laser beam, and an amplifier configured to amplify an energy of the pulse laser beam. A modified and amplified beam to laser peen a target part may have an energy of about 5J to about 10 J, an average power (defined as energy (J) x frequency (Hz)) of from about 25 W to about 200 W, with a flattop beam uniformity of less than about 0.2. The diode-pumped solid-state oscillator may be configured to output a beam having both a single longitudinal mode and a single transverse mode, and to produce and output beams at a frequency of about 20 Hz.

Apparatus and methods for altering one or more spectral, spatial, or temporal characteristics of a light-emitting device are disclosed. Generally, such apparatus may include a volume Bragg grating (VBG) element that receives input light generated by a light-emitting device, conditions one or more characteristics of the input light, and causes the light-emitting device to generate light having the one or more characteristics of the conditioned light.

The present invention benefits from the determination that pre-selected spectral bandwidths that avoid the spectrum of an electronic transition of a metal/alloy vapor allow for welds substantially free from detritus that may discolor the weld. Accordingly, the present invention provides analytical methods, welding methods and fiber lasers configured to provide high quality metal/alloy welds.

Orbital debt is removal (ODR) systems under the present approach may use a ground- or surface-based FEL and mirror system with sufficient power and both spatial and temporal resolution to both locate Category II OD (1 cm to 10 cm diameter) in low Earth orbit (LEO, 160 to 2000 km altitude) and remove these objects from orbit. Locating the Category II OD is performed by having, the light beam from an FEL and its beam director scan a volume of space of interest and then observing the light reflected from the OD. Removing the OD may include heating the OD to a sufficiently high temperature to evaporate the OD, changing the orbit of the OD such as to lower the perigee, or both. Megawatt-class MOPA FELs for, inter alia, removing OD, are described.

Orbital debt is removal (ODR) systems under the present approach may use a ground- or surface-based FEL and mirror system with sufficient power and both spatial and temporal resolution to both locate Category II OD (1 cm to 10 cm diameter) in low Earth orbit (LEO, 160 to 2000 km altitude) and remove these objects from orbit. Locating the Category II OD is performed by having, the light beam from an FEL and its beam director scan a volume of space of interest and then observing the light reflected from the OD. Removing the OD may include heating the OD to a sufficiently high temperature to evaporate the OD, changing the orbit of the OD such as to lower the perigee, or both. Megawatt-class MOPA FELs for, inter alia, removing OD, are described.

A laser amplifier device including an amplification element which includes a solid-state gain medium including a first main face and a second main face separated from each other by a distance which is smaller than the lateral dimensions. A heat spreader is thermally connected to, and substantially covering, the first main face. The heat spreader is optically transparent to a pump light and is in thermal contact with a heat sink. A first reflector substantially covers and faces the first main face and a second reflector substantially covers and faces the second main face; the reflectors being configured to reflect the pump light. The heat spreader and the first reflector are arranged such that the pump light passes through the heat spreader and through the first reflector and is reflected multiple times across the amplification element, between the first and second reflectors.

A laser apparatus that can generate a high-quality laser beam is provided. The laser apparatus is provided with a laser medium and an insulation layer. The laser medium has a first surface and a second surface. Incident laser light is incident on the first surface. The second surface totally reflects the incident laser light that is incident to the second surface at an incident angle equal to or larger than a critical angle. The insulation layer covers a second area of the second surface that surrounds a first area of the second surface, the first area totally reflecting the incident laser light. The laser medium is exposed in the first area.