This article presents a unified formulation and review of an extensive class of radiation effects and devices based on free or quasifree electrons. The effects and devices reviewed include slow-wave radiators [such as Cerenkov, Smith-Purcell, and TWT (traveling-wave tube) effects and devices], periodic bremsstrahlung radiators [such as undulator radiation, magnetic bremsstrahlung FEL's (free-electron lasers), and coherent bremsstrahlung in the crystal lattice], and transverse-binding radiators [such as the CRM (cyclotron resonance maser) and channeling radiation]. Starting from a general quantum-electrodynamic model, both quantum and classical effects and operating regimes of these radiation devices are described. The article provides a unified physical description of the interaction kinematics, and presents equations for the characterization of spontaneous and stimulated radiative emission in these various effects and devices. Universal relations between the spontaneous and stimulated emission parameters are revealed and shown to be related (in the quantum limit) to Einstein relations for atomic radiators and (in the classical limit) to the relations derived by Madey for magnetic bremsstrahlung FEL for on-axis radiative emission. Examples for the application of the formulation are given, estimating the feasibility of channeling radiation x-ray laser and optical regime Smith-Purcell FEL, and deriving the gain equations of magnetic bremsstrahlung FEL and CRM for arbitrary electron propagation direction, structure (wiggler) axis, and radiative emission angle.

We present a temperature-dependent Sellmeier equation for the refractive index of stoichiometric LiTaO3. The extraordinary refractive index, for the range 0.39-4.1 microm and for temperatures of 30-200 degrees C, are based on previously published data [Jpn. J. Appl. Phys. 41, 465 (2002)] and on measured data derived from quasi-phase-matched (QPM) resonances. We used the new Sellmeier coefficients that we obtained to calculate the QPM wavelengths for an optical parametric oscillator (OPO) based on periodically poled stoichiometric LiTaO3 pumped at 1064 nm. The measured wavelengths of the OPO were in good agreement with our predictions.

We describe the preparation of zirconia and hybrid zirconia-ORMOSIL planar waveguides by sol-gel technology at room temperature. Acetic acid was used as chelating agent to stabilize the zirconia precursor. Multimode light guiding was demonstrated for the first time in zirconia films prepared by the sol-gel method. The properties of the films, refraction index, thickness, and transparency as well as structural characterization using Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy (XPS), thermal analysis, and X-ray diffraction (XRD), were studied. The zirconia film contains propoxy, acetate, and hydroxyl ligands. In the zirconia-ORMOSIL films Zr-O-Si bonds were found, although homocondensation bonds are favored. The mechanism proposed for the structural results involves condensation of oligomeric species that react by ligand exchange. XRD show wide peaks at angles in area of 2Θ ) 4-10°. These peaks can be attributed to oligomeric structures with d spacing values of about 10 Å. The hybrid films are hydrophobic and XPS measurements shows that the surface is covered mainly by organic groups of the ORMOSIL. Films doped by pH indicator Methyl Red showed reversible response to acid and base vapors; this opens the possibility to use such films as waveguide-based optical sensors.

Room temperature persistent spectra hole burning in Sm2+doped silicate glasses prepared by the solgel process Appl.Planar waveguides of TiOrorganically modified silanes deposited on glass substrates were prepared by the sol-gel method, either in a pure form or doped by red perylimide laser dye, and their optical properties characterized. The refractive index increases and film thickness decreases as TiOz contents rise. Waveguiding in the pure film and the trapped luminescence in the doped films were measured. Typically three guided modes were observed.

Glass waveguiding films were prepared from titania and modified silica using the sol-gel method and doped by the laser dye rhodamine B. The guided and amplified fluorescence (pumped by a double frequency Nd-YAG laser) was coupled out either by static grating written on the film or by a prism. The gain of the emitted superradiance was determined from the amplified spontaneous emission intensity dependence on the pumped strip length. A maximum net gain of 54 dB/cm was measured.