Composite Ground Modification System: Vibroreplacement and Dynamic Compaction, Salt Lake County Detention Center, Utah

The site for a new Adult Detention Center currently under construction in Salt Lake City, Utah, is underlain by loose sands and soft clayey lake deposits. Due to bearing capacity, static settlement, and liquefaction concerns, a hybrid ground improvement program consisting of both dynamic compaction and vibroreplacement was implemented. Stone columns were concentrated under spread and wall footings; dynamic compaction was performed over the whole site. A comprehensive quality assurance/ quality control program was executed, with a significant number of cone penetration tests, standard penetration tests, 10 plate load tests, and deceleration readings taken with an accelerometer mounted on the dynamic compaction weight. This large body of data enabled the authors to assess the effectiveness of the ground improvement program, as well as analyze the results of the experimental deceleration readings

Counter-propagating entangled photons from a waveguide with periodic nonlinearity

The conditions required for spontaneous parametric down-conversion in a waveguide with periodic nonlinearity in the presence of an unguided pump field are established. Control of the periodic nonlinearity and the physical properties of the waveguide permits the quasi-phase matching equations that describe counter-propagating guided signal and idler beams to be satisfied. We compare the tuning curves and spectral properties of such counter-propagating beams to those for co-propagating beams under typical experimental conditions. We find that the counter-propagating beams exhibit narrow bandwidth permitting the generation of quantum states that possess discrete-frequency entanglement. Such states may be useful for experiments in quantum optics and technologies that benefit from frequency entanglement.Comment: submitted to Phys. Rev.

Picosecond laser source at 1 MHz with continuous tunability in the visible red band

We report the first demonstration to our knowledge of a continuously tunable picosecond laser operating around 1 MHz. The emission can be tuned from 640 to 685 nm and the repetition rate from 200 kHz to 1 MHz with a pulse duration of less than 200 ps. The system is based on a Nd:YVO4 passively Q-switched microchip laser providing a few tens of nJ per pulse. Two cascaded stages of amplification are then used to increase the pulse energy to several microJ . The frequency doubled radiation is then used to pump a periodically-poled-niobate-lithium (PPLN)-based optical parametric generator in an all-solid-state architecture. 20 nJ of tunable signal radiation are obtained. We also demonstrated 300-ps pulses generation in the UV (355 nm) at 1 MHz

Physical Basis of the Domain Engineering in the Bulk Ferroelectrics

We present a review of our theoretical and experimental investigations of the domain engineering aspects of domain structure development. Particular attention is paid to the processes governing the fabrication of periodic domain patterns