Abstract: A laser diode driver with means for adjusting the compliance voltage to allow a current source to accurately reproduce a current command while simultaneously minimizing the power dissipation of the current source. For a slowly-varying or DC current command, the compliance voltage is continuously adjusted to limit the power dissipation of the current source to below a predetermined minimum. For a pulsed current waveform, the compliance voltage is maximized during periods of zero or low current demand so that sufficient energy is stored to faithfully reproduce the leading edge of a pulsed current command, and reduced during the plateau portion of a pulsed current command to minimize the power dissipation of the current source.

Abstract: A laser diode driver with means for adjusting the compliance voltage to allow a current source to accurately reproduce a current command while simultaneously minimizing the power dissipation of the current source. For a slowly-varying or DC current command, the compliance voltage is continuously adjusted to limit the power dissipation of the current source to below a predetermined minimum. For a pulsed current waveform, the compliance voltage is maximized during periods of zero or low current demand so that sufficient energy is stored to faithfully reproduce the leading edge of a pulsed current command, and reduced during the plateau portion of a pulsed current command to minimize the power dissipation of the current source.

Abstract: An adjustable bipolar current source for a load, such as a thermoelectric cooler, includes a voltage-controlled power supply having a unipolar output, and an H-bridge. At least one of the two active elements on a first side and at least one of the two active elements on a second side of the H-bridge comprises an active conductive element responsive to a control signal to set a magnitude of current flow through the active conductive element. Control logic provides the control signals to the active elements on the first and second sides to set the polarity of the current to the load. Logic coupled to the voltage-controlled power supply maintains a supply voltage sufficient to maintain a voltage drop across the active conductive elements within a linear range of operation of the conductive elements. The output of the voltage-controlled power supply is clamped at or near a minimum stable level.

Abstract: An adjustable bipolar current source for a load, such as a thermoelectric cooler, includes a voltage-controlled power supply having a unipolar output, and an H-bridge. At least one of the two active elements on a first side and at least one of the two active elements on a second side of the H-bridge comprises an active conductive element responsive to a control signal to set a magnitude of current flow through the active conductive element. Control logic provides the control signals to the active elements on the first and second sides to set the polarity of the current to the load. Logic coupled to the voltage-controlled power supply maintains a supply voltage sufficient to maintain a voltage drop across the active conductive elements within a linear range of operation of the conductive elements. The output of the voltage-controlled power supply is clamped at or near a minimum stable level.

Abstract: An optical system modifies the optical orientation of the individual sources of a laser diode array so that the illumination provided by said individual sources may be combined into a single target location, while providing illumination at said target with the brightness of the individual sources. A first set of uniformly-spaced parallel light beams, said parallel beams defining a horizontal plane, is repositioned into a second set of uniformly-spaced parallel light beams, also defining a second horizontal plane but propagating in a direction perpendicular to the original light beams, with said second horizontal plane offset from said first horizontal plane, while the relative orientation of the high-brightness and low-brightness axes of said light beams with respect to the horizontal is interchanged. Three transformers are used to accomplish this reorientation.

Abstract: A diode pumped laser wherein third harmonic generation at 355 nm is obtained from an intra-cavity-tripled diode-pumped Nd:YVO4 crystal utilizing an angle-tuned LBO doubler and tripler, and operated at high repetition rates and good overall efficiency. An average UV power of over 2 watts at 30 kHz and 1 watt at 100 kHz is typically obtained with a 20 watt diode array "bar" side-pumping a one percent (1%) Nd:YVO4 (vanadate) slab. The device utilizes room temperature intra-cavity doubling and takes advantage of a small beam waist at the doubler and tripler required with low-power CW diode pumping.

Abstract: A protective coating [26] and a method for applying the same on an optically pumped solid state laser [10] having a lasing medium in the form of a slab [12] with at least two opposed parallel pumping faces [18, 20] between which a laser beam [11] propagates along a zig-zag path dictated by total internal reflection between these pumping faces. The slab [12] has an input face [14] for coupling in the laser beam and an output face [16] for coupling it out. The protective coating [26] is an organic synthetic, processed thermoplastic, or thermosetting polymer. Preferred materials include polymethylmethacrylate (PMMA), polyvinylidene chloride (PVC), polyethylene, polyimide, and Mylar.The protective coating [26] is applied onto the slab [12] from a solution in which the solvent is selected from the group of materials consisting of ketones, esters, and perfluorinated solvents.

Abstract: Alignment of a birefringent device characterized by a first face and a second face cut at Brewster's angle so that a plane of polarization is defined. The optical device is secured in the optical path by a rotatable member having an axis of rotation that is normal to the Brewster faces of the optical device. Coupled with the rotatable member on the axis of rotation is a support allowing adjustment of the angular position about the axis of rotation of the rotatable member. An operator adjusts the angular position of the rotatable member until the C-axis lies in the plane of polarization. Even though the C-axis may not be parallel to the direction of polarization, the depolarization effects of the misalignment are eliminated by proper adjustment of the angular position relative to the plane of polarization. A tunable, solid state laser using the alignment apparatus with a birefringent filter achieves greater linear tuning range.

Abstract: Alignment of a birefringent tunable laser gain medium characterized by a first face and a second face cut at Brewster's angle so that a plane of polarization is defined. The gain medium is secured in the optical path by a rotatable member having an axis of rotation that is normal to the Brewster faces of the optical device. Coupled with the rotatable member is a support allowing adjustment of the angular position about the axis of rotation fo the rotatable member. An operator adjusts the angular position of the rotatable member until the C-axis of the gain medium lies in the plane of polarization. Even though the C-axis may not be parallel to the direction of polarization, the depolarization effects of the misalignment are eliminated by proper adjustment of the angular position relative to the plane of polarization. A tunable, solid state laser using the alignment apparatus with a birefringent filter achieves greater linear tuning range.

Abstract: A tunable solid state laser having a titanium:sapphire grain medium and a birefringent filter mounted within a resonant cavity is provided. The resonant cavity is longitudinally pumped. The cavity is enclosed in a casing which has a small window admitting the pump beam into the resonant cavity, and a small window with an anti-reflection coating allowing the laser output to exit the casing. The casing is maintained at a positive pressure of nitrogen gas during operation of the laser to purge the resonant cavity of air and water vapor.

Abstract: A longitudinally pumped laser is characterized by one segment in which the cavity mode is astigmatic. A solid state medium is mounted within the one segment, so that a volume of the astigmatic cavity mode within the laser medium defines a cavity mode volume. A pump beam is supplied collinearly with the cavity mode through a means causing astigmatic focusing of the pump beam in the laser medium to define a pumped volume within the laser medium. The astigmatically focusing means is mounted according to a precalculated parameter that achieves the best possible average match of the pumped volume with the cavity mode volume, in light of the physical limitations on layout of the resonant cavity. The one segment may be defined by a first off-axis spherical mirror and a second off-axis spherical mirror, with a Brewster-cut solid state medium mounted in between.