BACKGROUND AND OBJECTIVES The process of altering the shape of cartilage using heat has been referred to as thermoforming, and presents certain clinical benefits in reconstructive surgical procedures within the head and neck. Thermoforming allows cartilage in the upper airway and face to be reshaped without the use of classic surgical maneuvers such as carving, morselizing, or suturing. The goa...

The Stark components of the F3=2, I9=2 and I11=2 manifolds have been characterized using the ̄uorescence spectra for the F3=2 ® I9=2 and F3=2 ® I11=2 transitions of Nd3‡in YVO4 laser host. The thermal e€ects on the width and position of the popular laser line at 1061.7 nm (R1 ® Y1) of the inter-Stark transition within the F3=2 ® I11=2 intermanifold transition of Nd3‡:YVO4 have also been investi...

A laminar boundary layer separates in a region of adverse pressure gradient on a flat plate, undergoes transition, and finally the turbulent boundary layer reattaches. Laminar-turbulent transition within this laminar separation bubble (LSB) is investigated by means of measurements with a Laser-Doppler-Anemometer (LDA), flow visualization in water and direct numerical simulation (DNS). The role ...

We investigate the absorption spectrum of a laser driven V system in which one of the upper levels is metastable. If the Rabi frequency of the laser driving the metastable transition is suuciently small we nd an extremely narrow peak in the stationary absorption spectrum of a weak probe on the strong transition. We give analytical expressions approximating the stationary absorption spectrum. Th...

A diode laser sensor was developed for partial pressure and temperature measurements using a single water vapor transition. The Lorentzian half-width and line intensity of the transition were calibrated for conditions relevant to proton exchange membrane (PEM) fuel cell operation. Comparison of measured and simulated harmonics from wavelength-modulation spectroscopy is shown to yield accuracy o...

The laser cooling and trapping of ultracold neutral dysprosium has been demonstrated recently using the broad, open, 421-nm cycling transition. Narrow-line magneto-optical trapping of Dy on longer wavelength transitions would enable the preparation of ultracold Dy samples suitable for loading optical dipole traps and subsequent evaporative cooling. We have identified the closed 741-nm cycling t...

We propose to use a cloud of laser-cooled atoms in a quasi-two-dimensional trap to investigate a nonequilibrium collapse phase transition in the presence of a gravitational-like interaction. Using theoretical arguments and numerical simulations, we show that, like in two-dimensional gravity, a transition to a collapsed state occurs below a critical temperature. In addition and as a signature of...

Under reducing conditions, single crystal of LiYF4 doped with 762 ppm of u3+ were obtained. Absorption andfluorescence spectra of this system are presented as well as the energy level scheme of the lasing 4 4 transition. Oscillator strength and laser cross section between Stark levels of the + 19,2 transition are calculated.

An extended-cavity diode laser at 852 nm has been built especially for the purpose of cooling and probing cesium atoms. It is a compact, self-aligned, and continuously tunable laser source having a 100-kHz linewidth and 60-mW output power. The electronic control of the laser frequency by the piezodriven external reflector covers a 4.5-kHz bandwidth, allowing full compensation of acoustic freque...

Monodispersed poly(N-isopropylacrylamide) (PNIPAM) nanoparticles, with hydrodynamic radius less than 50 nm at room temperature, have been synthesized in the presence of a large amount of emulsifiers. These microgel particles undergo a swollen–collapsed volume transition in an aqueous solution when the temperature is raised to around 34 °C. The volume transition and structure changes of the micr...