Matthew John Dejneka

The luminescence and structure of novel transparent oxyfluoride glass-ceramics

Abstract New transparent oxyfluoride glass-ceramics can provide a low phonon energy fluoride environment for active rare earth ions while maintaining the formability and physical properties of an oxide glass. Transparent glass-ceramics were made by casting crucible melted glass onto a steel plate and subsequently heating the resultant glass patty above the glass transition temperature to nucleate and grow LaF3 crystals. Eu3+ doped glasses emit only red luminescence from the 5D0 level but after heat treatment emit blue, green, and red luminescence indicative of a low phonon energy rare earth environment. TEM micrographs and XRD show no features in the base glass, but do show extensive LaF3 crystallites after heat treatment that are responsible for the novel optical properties of these hybrid materials.

Rare earth-doped glass microbarcodes

The development of ultraminiaturized identification tags has applications in fields ranging from advanced biotechnology to security. This paper describes micrometer-sized glass barcodes containing a pattern of different fluorescent materials that are easily identified by using a UV lamp and an optical microscope. A model DNA hybridization assay using these “microbarcodes” is described. Rare earth-doped glasses were chosen because of their narrow emission bands, high quantum efficiencies, noninterference with common fluorescent labels, and inertness to most organic and aqueous solvents. These properties and the large number (>1 million) of possible combinations of these microbarcodes make them attractive for use in multiplexed bioassays and general encoding.

Effect of the matrix on the radiative lifetimes of rare earth doped nanoparticles embedded in matrices

The radiative lifetimes, τR, of the excited states of rare earth (RE) ions contained in nanocrystalline insulators are different compared to their values in crystallographically equivalent bulk crystals. Their lifetimes depend on the effective index of refraction of the media consisting of nanoparticles and the substance filling the space between them. Here the radiative rates were studied as a function of particle size and the amorphous matrices containing the nanoparticles. Effects due to the effective index of refraction and site distortions associated with the increased inhomogeneous broadening were observed.

Studies of the spectroscopic properties of Pr3+ doped LaF3 nanocrystals/glass

Abstract Emission and excitation spectra are presented for praseodymium (Pr 3+ , 0.01 at%) doped oxyfluoride glass host containing LaF 3 nanocrystals. Two types of Pr 3+ ions, those in LaF 3 nanocrystals and those in the glass host, are characterized by spectroscopic and dynamical studies. Pr 3+ ions in the glass are selectively excited by pumping the 4f5d band and UV emission is observed. For Pr 3+ ions in the glass, the relaxation of 3 P 0 is dominated by multi-phonon processes to 1 D 2 .

Spectroscopic properties of Er3+ and Eu3+ doped acentric LaBO3 and GdBO3

This work studies the spectroscopic behavior of Eu3+-doped and Yb3+/Er3+-codoped single crystals of orthorhombic LaBO3 and rhombohedral GdBO3. Emissions from Er3+ at ∼1535 nm are shown to exhibit multiple narrow linewidth emissions. Luminescence from the 5D0→7F1, 7F2 transitions of Eu3+ is found to depend on the choice of LaBO3 or GdBO3 as a parent phase in a well-defined manner. Phonon sideband spectroscopy of the Eu3+ 5D2 excitation, corroborated using Raman spectroscopy, indicates that the highest energy phonon is less than 1400 cm−1 for the LaBO3 and less than 1010 cm−1 for the GdBO3. Further, absorption spectrum to 190 nm is provided for the GdBO3 clearly showing the 6I manifold, and the rarely seen 6D levels. Excitation of the 6D7/2 state at 250 nm in GdBO3 is shown to yield a strong ultraviolet emission centered at 314 nm. This work marks the lanthanide borates as candidate single crystals for active and nonlinear materials for UV, visible, and telecommunication band applications.

Spectral hole burning in thulium-doped glass ceramics.

We have used spectral hole burning to measure the homogeneous linewidth of the (3)H(6)(1)- (3)F(3)(1) transition of Tm(3+) ions doped into oxyfluoride glass ceramics consisting of nanocrystals of LaF(3) in an aluminosilicate glass matrix. From the magnitude of the hole width in the nanocrystals and its dependence on temperature, we propose that excitation of tunneling modes in the adjacent glassy phase as well as of confined mechanical modes in the nanocrystals is responsible for the broadening.

Rare-earth fluorescence in novel oxyfluoride glasses and glass-ceramics

Transparent oxyfluoride glass-ceramics can provide a low- phonon energy fluoride environment for active rare earth ions while maintaining the durability, formability, and mechanical strength of an oxide glass. Fluorescence from RE doped samples indicate substantial partitioning into the fluoride crystals. Eu3+ doped glasses emit only red luminescence from the 5D0, but after treatment emit blue, green, and red luminescence, indicative of a low phonon energy rare earth environment. Er3+ doped samples show broadening and flattening of the 1530 emission band upon heat treatment, making them attractive for broad band amplifiers. Cerammed Pr3+ doped samples exhibit 240 microsecond(s) 1G4 fluorescent lifetimes, which indicates a 1310 nm quantum efficiency of 8%. It was determined that active rare earth partitioning into the LaF3 nanocrystallites that form upon heat treatment are responsible for the novel optical properties of these hybrid materials.

Progress in high-power fiber lasers

We review current work on fiber laser systems at Corning. In particular, we describe design and performance of all-glass double-clad laser fibers, broad-area laser pumps, and pump coupling optics. We discuss our approaches using single-polarization fiber and low-nonlinearity photonic band gap fiber as technologies for developing the next generation of high-power fiber lasers.

Interaction of rare earth ions doped in nanocrystals embedded in amorphous matrices with two-level systems of the matrix

The interactions of rare earth ions doped in nanoparticles with the amorphous matrix in which they are embedded are studied with hole burning and fluorescence line narrowing techniques. The results suggest that at low temperatures the homogeneous broadening of optical transitions of the rare earth ions are dominated by interactions with the two-level systems of amorphous matrix. At higher temperatures other phonon-induced processes which are seen in bulk single crystals dominate the dynamics.

69.2: Designing Strong Glass for Mobile Devices

Compared to plastic, glass is tougher, scratch resistant, offers optical quality and a richer look for consumer electronic applications. The mechanical performance of silicate glasses can be improved via ion-exchange in molten salts. Variables that affect the ion-exchange process, such as glass composition, thermal history, time, temperature, and bath chemistry will be discussed.