Abstract: A controllable single-photon source having a single illuminated molecule in a condensed phase host is provided. The single molecule is illuminated with a pulse of radiation having a wavelength such that the molecule is excited to a vibrational state higher in energy than an associated excited electronic state. The molecule rapidly, incoherently and irreversibly decays, with a lifetime Tvib, from the vibrational state to the excited electronic state by transferring the corresponding vibrational energy to the host. The excited electronic state has a lifetime T, and with high probability the single molecule makes a radiative transition from this state to emit a single photon. The pump pulse duration Tp satisfies the condition Tvib<Tp<T. Room temperature operation and spectral separation of pump and single-photon radiation are thereby provided. A semiconductor nanocrystal can be used instead of a molecule.

Abstract: A controllable single-photon source having a single illuminated molecule in a condensed phase host is provided. The single molecule is illuminated with a pulse of radiation having a wavelength such that the molecule is excited to a vibrational state higher in energy than an associated excited electronic state. The molecule rapidly, incoherently and irreversibly decays, with a lifetime Tvib, from the vibrational state to the excited electronic state by transferring the corresponding vibrational energy to the host. The excited electronic state has a lifetime T, and with high probability the single molecule makes a radiative transition from this state to emit a single photon. The pump pulse duration Tp satisfies the condition Tvib<Tp<T. Room temperature operation and spectral separation of pump and single-photon radiation are thereby provided. A semiconductor nanocrystal can be used instead of a molecule.

Abstract: The present invention provides for the generation of a controllable source of single photons generated one at a time using optical pumping of a single molecule at room temperature. A single fluorescent molecule is pumped by a light source so that the molecule is placed in its electronic excited state with high probability. The molecule then de-excites via the emission of a single photon, which can be collected by a means for collecting. The room temperature source of single photons is far more convenient and therefore more widely applicable. A high probability of single-photon emission for each incident pump pulse is provided, a property which is useful for transmission of sensitive data bits by the methods of quantum cryptography.

Abstract: Photochromic fluorescent protein moiety having two or more stable states having excitation or emission spectra that are shifted from one wavelength region to another wavelength region in the two states are described. The photochromic material switches between states by irradiation with light of appropriate wavelengths. The two states are preferably stable at room temperature and in the dark. The switching between states can be reversible.

Abstract: The present invention relates to a three-component optical photorefractive article having improved diffraction efficiency. The article comprises (i) nonphotoconductive polymer, (ii) benzimidazoline, and (iii) a sensitizer.

Abstract: The present invention relates to polymeric materials that exhibit an erasable photorefractive effect which can be fabricated into optical devices such as optical wave guides.

Abstract: The present invention relates to an improved process for producing photorefractive net gain two beam coupling utilizing polymeric materials.

Abstract: The present invention relates to polymeric materials that exhibit an erasable photorefractive effect which can be fabricated into optical devices such as optical wave guides.

Abstract: A phase-sensitive ultrasonic modulation method for the detection of strain-sensitive spectral features involves the use of an ultrasonic field with well-defined wavefronts and a light beam of spot size less than the ultrasonic wavelength and of linewidth less than that of the spectral feature. When the light wavelength coincides with the wavelength of the spectral feature, the ultrasonic wave shifts, splits, or broadens the absorption lineshapes of the various centers contributing to the spectral feature thereby changing the amplitude or phase of the light beam or emitted fluorescence in synchrony with the ultrasonic field.