Emission and excitation spectra of chromone and 6-fluorochromone have been measured in the vapor phase at different temperatures and pressures along with the absorption spectra. The emission is shown to consist of the (n, *) phosphorescence accompanied by weak S1(n, *) delayed fluorescence. It is inferred from the temperature dependence of the phosphorescence intensity that the (n, *) state ...

Fluorescence measurements are easily made with the aid of a cryogenic fiber optic probe. Emission wavelength time matrixes, excitation emission matrixes, and time-resolved excitation emission matrixes are rapidly collected with a pulsed tunable dye laser, a spectrograph, and an intensified charged-coupled device. Compound identification is based on spectral and lifetime information. The potenti...

We present an experimental and theoretical study on the gain mechanism in a photonic-crystal-cavity nanolaser with embedded quantum dots. From time-resolved measurements at low excitation power we find that four excitons are coupled to the cavity. At high excitation power we observe a smooth low-threshold transition from spontaneous emission to lasing. Before lasing emission sets in, however, t...

Dipicolinic acid (DPA) and the Ca2+ complex of DPA (CaDPA) are major chemical components of bacterial spores. With fluorescence being considered for the detection and identification of spores, it is important to understand the optical properties of the major components of the spores. We report in some detail on the room-temperature fluorescence excitation and emission spectra of DPA and its cal...

We discuss the rotational excitation of small interstellar grains and the resulting electric dipole radiation from spinning dust. Attention is given to excitation and damping of grain rotation by: collisions with neutrals; collisions with ions; “plasma drag”; emission of infrared radiation; emission of electric dipole radiation; photoelectric emission; and formation of H2 on the grain surface. ...

Coupling between spatially separated zero-dimensional states has been observed in a system of selfassembled In0.55Al0.45As quantum dots. Photoluminescence excitation spectra, taken at 4.2 K with a near-field scanning optical microscope, reveals narrow resonances in the emission lines of individual dots when the excitation energy is tuned below the barrier band edge. A fraction of these resonanc...

Cathodoluminescence spectroscopy has been performed on silver nanoparticles in a scanning electron microscopy setup. Peaks appearing in the visible range for particles fabricated on silicon substrate are shown to arrive from excitation of out-of-plane eigenmodes by the electron beam. Monochromatic emission maps have been shown to resolve spatial field variation of resonant plasmon mode on lengt...

BACKGROUND AND OBJECTIVE The objective of this study was to explore whether fluorescence spectroscopy signatures differed between normal variations within the ovary, benign neoplasms, and ovarian cancer. STUDY DESIGN/MATERIALS AND METHODS Ovarian tissue fluorescence emission spectra were collected sequentially at 18 excitation wavelengths ranging from 330 to 500 nm from 11 patients undergoing...

Using combined excitation–emission spectroscopy we have studied the erbium incorporation into GaN and InGaN for in situ doped MOCVD-grown layers and compared them to samples grown by MBE. A smaller up-conversion efficiency for the main site is observed compared to minority sites in the same sample as well as versus all sites from MBE grown samples. Furthermore, we show that the 1.54 lm emission...

We present medium-resolution (R ∼ 700) near-infrared (λ = 1 − 2.5 μm) spectra of a sample of planetary nebulae (PNe). A narrow slit was used which sampled discrete locations within the nebulae; observations were obtained at one or more positions in the 41 objects included in the survey. The PN spectra fall into one of four general categories: H I emission line-dominated PNe, H I and H2 emission...