Abstract: A power MOSFET linear amplifier includes a plurality of paralleled MOSFETS having a gate-to-source resistor to ensure simultaneous turn-on and sharing of the load current. An arc lamp is connected in series with a 400 volt power supply and a variable ballast element in the form of the power MOSFET linear amplifier. The linear amplifier includes four similar modules. Each module is a hybrid circuit constructed with eight MOSFETs connected in parallel. Each MOSFET includes a similar gate-to-source resistor in addition to an appropriate gate resistor and source resistor. Under operating load current conditions, the gate-to-source resistors are laser trimmed to establish precise equalized current sharing in response to the specified operating input voltages. The module is set with the gate voltage slightly above the operating threshold voltage range of the MOSFET.

Abstract: A dye laser system especially useful for generating short pulses in response to excitation laser pulses directed to an appropriate dye contained between opposing mirrors that form a short cavity within a small, easily replaceable cell. The spacing of the mirrors is adjustable by application of a force from outside of the cell, thereby allowing control of the frequency of the laser output. The cell is self-contained, including a dye reservoir maintained in continuous liquid communication with the cavity for providing fresh dye to it.