Abstract: An external-resonator laser system having multiple laser elements is configured to permit each laser to undergo individual amplification notwithstanding optical beam combination. In this way, overall output power may be scaled in a desired fashion, depending on the selected characteristics of the optical amplifier elements. To achieve additional power, each of the amplifiers may implemented as a phased array. Viewed more generally, a phased-array configuration affords beam combining in two stages, with each contributing input source itself composed of multiple sources whose outputs have been combined. If each phased-array source emits at a different wavelength, this design offers a multi-wavelength output whose power level may be scaled in accordance with the number and character of the devices forming each phased array.

Abstract: A single laser crystal is driven with multiple pumping sources to obtain discrete, collimated outputs without substantial thermal crosstalk, so that the action of one pumping source does not adversely interfere with the action of another source driving the same crystal; that is, an imaging output emanating from one crystal region will neither defeat nor spuriously cause an imaging output in another region.

Abstract: An interactive exercise apparatus engages a user's mind and body. The apparatus comprises an exercise mechanism and a steering mechanism for manipulation by the user to achieve exercise and to indicate a direction of motion. The exercise mechanism can be, for example, the steps of a stair climbing simulator or the pedals of a bicycle, preferably a recumbent bicycle. A simulated environment (e.g., an interactive simulated three-dimensional environment or an interactive simulated three-dimensional fluid environment) is generated by a computer and displayed on a display system for the user. The user manipulates. the exercise mechanism and the steering mechanism to travel substantially unrestricted throughout the simulated environment. The computer controls the exercise mechanism and monitors the exercise mechanism and the steering mechanism to determine user position in the simulated environment. The display provides a visual display of the user's position in the simulated environment.

Abstract: A liquid cooled plasma arc cutting torch system includes a plasma arc torch, a torch receptacle and a cooling system. The torch is removably mounted to the receptacle. The cooling system includes a liquid storage tank, supply and return lines providing fluid communication paths between the tank and the receptacle and a pump for pumping the cooling liquid from the tank through the supply line, the receptacle, the torch and the return line. A valve coupled to the return line includes a nozzle that directs liquid toward an inside top surface of the tank. A flow restriction member may be provided to equalize pressure in the supply with atmospheric pressure when the pump is not operating. A pressurized gas source may be utilized to substantially clear the receptacle, torch and return line of liquid when the pump is not operating.