Towards an in situ, full-power gauge of the focal-volume intensity of petawatt-class lasers.

About 50 years ago, Sarachick and Schappert [Phys. Rev. D. 1, 2738-2752 (1970)] showed that relativistic Thomson scattering leads to wavelength shifts that are proportional to the laser intensity. About 28 years later, Chen et al. [Nature 396, 653-655 (1998)] used these shifts to estimate their laser intensity near 1018 W/cm 2. More recently, there have been several theoretical studies aimed at exploiting nonlinear Thomson scattering as a tool for direct measurement of intensities well into the relativistic regime. We present the first quantitative study of this approach for intensities between 1018 and 1019 W/cm 2. We show that the spectral shifts are in reasonable agreement with estimates of the peak intensity extracted from images of the focal area obtained at reduced power. Finally, we discuss the viability of the approach, its range of usefulness and how it might be extended to gauge intensities well in excess of 1019 W/cm 2.

Direct visualization of light confinement and standing wave in THz Fabry-Perot resonator with Bragg mirrors.

We report for the first time the ability to perform time resolved imaging of terahertz (THz) waves propagating within a Fabry-Perot resonator on a LiNbO3 slab. Electro-optic effect is used to record the full spatiotemporal evolution of THz fields inside the resonator. In addition to revealing the real-space behavior, the data further demonstrate the confinement and the standing wave modes of THz in the cavity in frequency domain. The experimental results are in good agreement with numerical simulations. Using the coherent imaging technique to gain real-time information about a resonator system provides a unique path to study the physics of optical cavity.

Contact resistance and phase slips in mesoscopic superfluid atom transport.

We have experimentally measured transport of superfluid, bosonic atoms in a mesoscopic system: a small channel connecting two large reservoirs. Starting far from equilibrium (superfluid in a single reservoir), we observe first resistive flow transitioning at a critical current into superflow, characterized by oscillations. We reproduce this full evolution with a simple electronic circuit model. We compare our fitted conductance to two different microscopic phenomenological models. We also show that the oscillations are consistent with LC oscillations as estimated by the kinetic inductance and effective capacitance in our system. Our experiment provides an attractive platform to begin to probe the mesoscopic transport properties of a dilute, superfluid, Bose gas.

Spatial shaping for generating arbitrary optical dipole traps for ultracold degenerate gases.

We present two spatial-shaping approaches - phase and amplitude - for creating two-dimensional optical dipole potentials for ultracold neutral atoms. When combined with an attractive or repulsive Gaussian sheet formed by an astigmatically focused beam, atoms are trapped in three dimensions resulting in planar confinement with an arbitrary network of potentials - a free-space atom chip. The first approach utilizes an adaptation of the generalized phase-contrast technique to convert a phase structure embedded in a beam after traversing a phase mask, to an identical intensity profile in the image plane. Phase masks, and a requisite phase-contrast filter, can be chemically etched into optical material (e.g., fused silica) or implemented with spatial light modulators; etching provides the highest quality while spatial light modulators enable prototyping and realtime structure modification. This approach was demonstrated on an ensemble of thermal atoms. Amplitude shaping is possible when the potential structure is made as an opaque mask in the path of a dipole trap beam, followed by imaging the shadow onto the plane of the atoms. While much more lossy, this very simple and inexpensive approach can produce dipole potentials suitable for containing degenerate gases. High-quality amplitude masks can be produced with standard photolithography techniques. Amplitude shaping was demonstrated on a Bose-Einstein condensate.

Analogs of basic electronic circuit elements in a free-space atom chip.

Using a thermal sample of laser-cooled rubidium atoms, we have constructed a neutral-atom circuit analogous to an electronic capacitor discharged through a resistor. The atoms are confined using what we call a free-space atom chip, an optical dipole trap created using a generalized phase-contrast imaging technique. We have also calculated theoretical values for the capacitance and resistance, which agree with our experiments, as well as theoretical value for an atomic analog of electrical inductance. We show that atomic capacitance is analogous to the quantum capacitance, the atomic resistance is analogous to the ballistic, or Sharvin resistance, and the atomic inductance is analogous to kinetic inductance.

Superflow in a toroidal Bose-Einstein condensate: an atom circuit with a tunable weak link.

We have created a long-lived (≈40 s) persistent current in a toroidal Bose-Einstein condensate held in an all-optical trap. A repulsive optical barrier across one side of the torus creates a tunable weak link in the condensate circuit, which can affect the current around the loop. Superflow stops abruptly at a barrier strength such that the local flow velocity at the barrier exceeds a critical velocity. The measured critical velocity is consistent with dissipation due to the creation of vortex-antivortex pairs. This system is the first realization of an elementary closed-loop atom circuit.

Frequency tuning of a distributed feedback dye laser with two transmission gratings.

Distributed feedback dye lasers, which use a holographic grating, present a very simple and reliable way to generate ultrashort pulses. We have developed a new technique for wavelength tuning of this type of laser by projecting the image of a second grating into the dye cell. Single-line operating and tuning was demonstrated with transform-limited output pulses on a picosecond time scale.

Generation of intense 10-ps, 193-nm pulses using simple distributed feedback dye lasers and an ArF(*) amplifier.

A pair of holographic distributed feedback dye lasers is used to generate 10-ps pulses at two selected wavelengths that are mixed in a BBO crystal to produce a pulse ~ 10 ps in duration at 193 nm. This seed pulse is subsequently amplified in an ArF(*) excimer laser to an energy of 10-15 mJ with <40 microJ in amplified spontaneous emission. The pulses are nearly transform limited and diffraction limited.

Harvey A.K. Whitney lecture. Taking charge of the profession.

The relationship between pharmacists' attitudes toward the profession and their career opportunities is described. Pharmacists must be committed to the idea that pharmacy is an essential component of health care. Pharmacy education needs to instill an attitude of service and excellence and an expectation of success. Social, political, economic, and professional change has challenged fundamental assumptions and values that made life predictable in the past. Pharmacists have permitted others to establish the scope and limits of professional pharmacy practice; it is time for pharmacists themselves to determine the future of their profession by focusing on providing services to fulfill unmet health-care needs. The profession as a whole will suffer if pharmacists view certain practice roles or settings as inferior. When all pharmacists accept "drug-use control" as the primary ethic that drives pharmaceutical decisions, the public, the government, and other health-care providers will respect that role for pharmacists. Studying the pharmacy literature can enhance pharmacists' positive feelings about their contributions. Pharmacists alone are responsible for the status of the profession and for changing what needs to be changed. By changing their thinking about the profession, pharmacists can broaden their career opportunities.

Study of particulate matter in carbenicillin disodium using scanning electron microscopy and microbeam x-ray spectrography.

A scanning electron microscopy membrane filtration study was conducted to determine the particulate contamination of samples of carbenicillin disodium which had been manufactured by bulk filling and by lyophilization. The bulk-filled product contained more contaminating particles than the lyophilized product. In both products, the number of particles increased logarithmically with decreasing particle size in the range measured (exceeding 0.1 micron). X-ray spectrographic analysis of particles larger than 0.5 micron revealed that the major particulate contaminates in both products were composed primarily of elements below atomic number 10. It is concluded that packaging of carbenicillin disodium by lyophilization of a solution results in significantly less submicrometer particulate contamination than packaging by sterile bulk filling of spray-dried powder.

Pharmacist-managed patient assessment and medication refill clinic.

The effectiveness of a pharmacist in determining the appropriateness of prescription renewal for patients appearing at a hospital-based refill clinic was investigated. In part 1, data were collected on the clinic as it traditionally functioned with staff physicians evaluating the patients. In parts 2 and 3, data were collected with the pharmacist assuming the assessment function. In part 2, a physician reviewed the pharmacist's decisions before the patient left. In part 3, the pharmacist functioned without supervision and the physician reviewed patient records retrospectively. Physician agreement with the pharmacist's decisions was the primary criterion for determining effectiveness, and was found to be 99% in part 2, for a total of 105 patients. In part 3, physician agreement remained at the 99% level for a total of 106 patients. Patient waiting time was about the same in each part of the study because of clinic procedures beyond the pharmacist's control. A pharmacist can be cost-effective in this role if the task is combined with regular pharmaceutical functions.

Saturated-interference spectroscopy.

The background in saturation spectroscopy is decreased by balancing the probe beam, in amplitude and phase, against a second probe, using a configuration like a Jamin interferometer. This improves the signal-to-noise ratio. If the phase is adjustable to provide best balance while the laser is tuned, the signal is proportional to the square of the absorption, and the line width is accordingly reduced.

Sperm antibodies after vasectomy with fulguration.

Whether antisperm antibodies develop after vasectomy probably depends on several variables, 1 of which may be the surgical technique. The levels of serum antisperm antibodies were compared in men vasectomized by 1 techniques: vasoligation and fulguration. No difference in the incidence of spermagglutinating antibody was found in the 2 groups. However, immobilizing antibodies were observed in 43 per cent of the men undergoing vasoligation but in only 29 per cent of the men vasectomized by fulguration.