Joseph A. Musser

Raman-excited spin coherences in nitrogen-vacancy color centers in diamond

Raman-excited spin coherences were experimentally observed in nitrogen-vacancy (N-V) diamond color centers by means of nondegenerate four-wave mixing and electromagnetically induced transparency. The maximal absorption suppression was found to be 17%, which corresponds to 70% of what is possible given the random geometric orientation of the N-V center in diamond. In the context of quantum computing in solids, this level of transparency represents efficient preparation of quantum bits, as well as the ability to perform arbitrary single-quantum-bit rotations.

Integrating cavities: temporal response

The temporal response of an integrating cavity is examined and compared with the results of a Monte Carlo analysis. An important parameter in the temporal response is the average distance d between successive reflections at the cavity wall; d was calculated for several specific cavity designs--spherical shell, cube, right circular cylinder, irregular tetrahedron, and prism; however, only the calculation for the spherical shell and the right circular cylinder will be presented. A completely general formulation of d for arbitrary cavity shapes is then derived, d =4V/S where V is the volume of the cavity, and S is the surface area of the cavity. Finally, we consider an arbitrary cavity shape for which each flat face is tangent to a single inscribed sphere of diameter D (a curved surface is considered to be an infinite number of flat surfaces). We will prove that for such a cavity d =2D/3, exactly the same as d for the inscribed sphere.

Flow-through integrating cavity absorption meter: experimental results

We report experimental results from a flow-through integrating cavity absorption meter. The operating range of the device is from 0.004 m(-1) to over 80 m(-1) of absorption. Absorption coefficients have been measured with 8% or less change in the presence of over 200 m(-1) of scattering in the medium. The instrument signal has been shown to be independent of flow rate up to 20 liters/min and thus independent of turbulence. This large operational range along with the ability to measure absorption independently of adverse scattering affects allows the instrument to be utilized in a wide range of environmental conditions.

First observation of ultraslow group velocity of light in a solid

We report ultraslow group velocities of light in a solid. Light speeds as slow as 45 m/s were observed, corresponding to a group delay of 66 microsecond(s) in a 3-mm thick, optically dense crystal of Pr doped Y2SiO5. Reduction of the group velocity is accomplished by using a sharp spectral feature in absorption and dispersion that is produced by resonance Raman excitation of a ground-state spin coherence. Potential applications of slow and stopped light for the highly efficient storage and recall of optical data are discussed.

An Instrument to Measure the Backscattering Coefficient b b for Arbitrary Phase Functions

We present the ocean optics community with the first instrumentation to directly measure the backscattering coefficient of natural waters for arbitrary phase functions. It is suitable for in situ applications and has the requisite resolution.

Ring-Down Absorption Spectroscopy in an Integrating Cavity

A new diffuse reflector has been developed whose reflectivity in the 250 nm to 1 micron spectral region is so high that ring-down spectroscopy of scattering aerosols in an integrating cavity is now possible.

Raman-excited spin coherences in N-V diamond

Raman excited spin coherences were experimentally observed in nitrogen-vacancy (N-V) diamond color centers via nondegenerate four-wave mixing (NDFWM) and electromagnetically induced transparency (EIT). The maximal EIT-induced absorption suppression was found to be 17%, which corresponds to 70% of what is possible given the four possible geometric orientations of the N-V center in diamond. The properties of these coherences are discussed in the context of potential applications to solid-state quantum computing and high-temperature spectral hole burning memories.

Raman excited spin coherences in N-V diamond

Summary form only given. The use of optical Raman interactions to excite spin coherences in solids has numerous potential applications, ranging from low-power nonlinear optics to high-temperature spectral hole burning memories to solid-state quantum computing. The interest in Raman excitation lies in the fact that the spin coherences can be efficiently excited and manipulated using optical laser fields yet are weakly coupled to the environment and hence have the long coherence lifetimes needed for optical memories and quantum computing. The interest in nitrogen-vacancy (N-V) color centers in diamond is its large optical oscillator strength. For memory, a large oscillator strength is important for high temperature operation. For quantum computing, the high optical transition rate enables the higher gate speed and the larger number of quantum logic operations that can be performed within the spin coherence lifetime.