Abstract: A wavelength conversion device 10 comprises a laser device 12 for radiating light beams, a collimeter lens system 18 including lenses 14, 16 for adjusting the wavefront and diameter of a light beam to condense light, a resonator 26 comprising mirrors 22, 24 of the same radius of curvature, and a crystal 20 located inside the resonator 26 near beam-condensing sites and having a large receptive angle. The resonator 26 is a confocal resonator wherein the focus and center of curvature of the mirror 22 are equal to those of the mirror 24 and the radius of curvature of the mirrors 22, 24 exceeds the curvature of the wavefront of light beams from the collimeter lens system 18. Therefore, when a light beam is reflected from the mirrors 22, 24, the curvature of its wavefront is changed and an SHG light comprising only light beams that pass through the forward path is output efficiently.

Abstract: Laser light radiated from a laser device 12 enters a resonator 16, and an electric field applied to a BBO crystal 14 inside the resonator 16 modulates the resonance frequency of the resonator 16. The BBO crystal 14 has a modulation electrode 32 and a feedback electrode 34, and a photodetector 18 detects laser light modulated by the BBO crystal 14. A signal in proportion to an error in resonance frequency obtained from the photodetector 18 causes an electric field to be applied to the BBO crystal 14 via the electrode 32 to change the resonance length. Negative feedback control is thus provided to the resonance frequency of the resonator 16 which is determined by the electric field applied to the BBO crystal 14 to substantially eliminate error, thereby synchronizing the resonator 16.

Abstract: A wavelength conversion apparatus using a nonlinear optical element for generating light different in wavelength from an incident fundamental wave. This apparatus utilizes a nonlinear optical element or a focusing lens element in the conversion apparatus to spatially separate light generated by the nonlinear optical element from the fundamental wave. For example, a cylindrical lens 13 for adjusting the size of the light beam is placed at least behind a wavelength conversion nonlinear optical crystal 12, and a light beam from the crystal 12 is passed through the lens near its edge, at a distance, from the central axis of the lens 13. The light beam is subject to a prism effect, and the generated beam B is separated from fundamental wave A as a result of the refractive index dispersion of the lens 13 and is transmitted.

Abstract: A sensing technique uses a variable precharge voltage sensing with a single bitline swing in a DRAM cell or array of DRAM cells so that the power dissipation is reduced. The bitline precharge voltage varies from one RAS cycle to the next RAS cycle depending upon the level of the data in the accessed cells. Such an arrangement eliminates the need for a reference voltage generator since the precharge voltage is not the same voltage for each RAS cycle.

Abstract: An apparatus for wavelength conversion of laser light which can prevent optical destruction of a wavelength conversion element and achieve a high wavelength conversion efficiency. The apparatus for wavelength conversion of laser light has an optical focusing system for focusing the input laser light on the wavelength conversion element in an optical cavity, which optical focusing system makes the cross-sectional shape of a light beam non-circular, for example, elliptical.

Abstract: A wordline driver circuit is shown for a DRAM, the circuit comprising a PMOS transistor structure having one contact coupled to a wordline, a second contact coupled to a negative voltage supply and a gate coupled to a control input, the transistor having an N-well about the gate, first and second contacts. An isolating structure is positioned about the N-well to enable it to be a separately controlled from surrounding N-well structures. Pulse circuits are coupled to the transistor for applying, when activated, a potential that enables the wordline to transition to a more negative potential. A bias circuit is also provided for biasing the N-well at a first potential and a second lower potential, the second lower potential applied when the pulse circuits are activated. As a result, body effects in the PMOS transistor are minimized while at the same time enabling a boost potential to be applied to the wordline.