We explore a single-photon approach to Rydberg state excitation and Rydberg blockade. Using detailed theoretical models, we show the feasibility of direct excitation, predict the effect of background electric fields, and calculate the required interatomic distance to observe Rydberg blockade. We then measure and control the electric field environment to enable coherent control of Rydberg states. With this coherent control, we demonstrate Rydberg blockade of two atoms separated by 6.6(3) µm. When compared with the more common two-photon excitation method, this singlephoton approach is advantageous because it eliminates channels for decoherence through photon scattering and ac Stark shifts from the intermediate state while moderately increasing Doppler sensitivity.

We measure and model parametric gain and oscillation for two crystals arranged for walkoff compensation. We show how the orientation of the crystals determines the relative sign of the nonlinear mixing coefficient in the two crystals. This sign dramatically influences small signal gain and oscillator performance, and we show how to determine the correct crystal orientation from parametric-gain measurements. The performance of two-crystal oscillators is examined with particular attention to beam tilts, conversion efficiency, and beam quality. We find reduced efficiency and increased oscillation threshold when the coefficients have opposite signs in a two-crystal ring oscillator. Sign reversal seems to have little influence on spectral purity or far-field beam profiles when the oscillator is seeded.

We report on the first demonstration of ZGP OPO based on Rotated Image Singly-Resonant Twisted RectAngle (RISTRA) cavity. For the OPO signal wave we achieved a near diffraction-limited beam at 3.4 mum with pulse energy of 10 mJ at repetition rate up to 500 Hz. As a pump source for the ZGP OPO, we utilized a 2-mum, TEM00, Ho:YLF MOPA system producing > 55 mJ energy per pulse at repetition rate range from single shot to 500 Hz.

We use the separated-beams method to measure the second-order nonlinear optical tensors of the crystals KTiOPO4, KTiOAsO4, RbTiOPO4, and RbTiOAsO4 for second-harmonic generation of 1064-nm light. Our results agree well with most previous measurements but have improved precision.

Pulsed power accelerators compress electrical energy in space and time to provide versatile experimental platforms for high energy density and inertial confinement fusion science. The 80-TW “Z” pulsed power facility at Sandia National Laboratories is the largest pulsed power device in the world today. Z discharges up to 22 MJ of energy stored in its capacitor banks into a current pulse that rises in 100 ns and peaks at a current as high as 30 MA in low-inductance cylindrical targets. Considerable progress has been made over the past 15 years in the use of pulsed power as a precision scientific tool. This paper reviews developments at Sandia in inertial confinement fusion, dynamic materials science, x-ray radiation science, and pulsed power engineering, with an emphasis on progress since a previous review of research on Z in Physics of Plasmas in 2005.