Abstract: A technique for generating variable pulse delays uses one or more nonlinear-optical processes such as cross-phase modulation, cross-gain modulation, self-phase modulation, four-wave mixing or parametric mixing, combined with group-velocity dispersion. The delay is controllable by changing the wavelength and/or power of a control laser. The delay is generated by introducing a controllable wavelength shift to a pulse of light, propagating the pulse through a material or an optical component that generates a wavelength dependent time delay, and wavelength shifting again to return the pulse to its original wavelength.

Abstract: A technique for generating variable pulse delays uses one or more nonlinear-optical processes such as cross-phase modulation, cross-gain modulation, self-phase modulation, four-wave mixing or parametric mixing, combined with group-velocity dispersion. The delay is controllable by changing the wavelength and/or power of a control laser. The delay is generated by introducing a controllable wavelength shift to a pulse of light, propagating the pulse through a material or an optical component that generates a wavelength dependent time delay, and wavelength shifting again to return the pulse to its original wavelength.

Abstract: A method and apparatus for generating a multi-wavelength pulse train use a technique referred to as time-lens compression. The time-lens is formed of a phase modulator in series with a dispersion element. In addition to pulse compression, this time-lens simultaneously displaces the pulses according to their center wavelengths, resulting in a temporally evenly spaced multi-wavelength pulse train. An aberration correction technique, based on the temporal analog of a spatial correction lens, can also be employed improve the quality of the compressed pulses. Through use of CW DFB lasers and electrooptic phase modulators, the all-fiber system allows complete tunability of temporal spacing, spectral profile and repetition rate.

Abstract: A technique for simultaneous spatial and temporal focusing of femtosecond pulses improves the signal-to-back-ground ratio (SBR) in multiphoton imaging. This is achieved by spatially separating spectral components of pulses into a “rainbow beam” and recombining these components at the spatial focus of an imaging system. The temporal pulse width becomes a function of distance, with the shortest pulse width confined to the spatial focus. The technique can significantly improve the axial confinement and reduce the background excitation in multiphoton microscopy, and thereby increase the imaging depth in highly scattering biological specimens.

Abstract: A method and apparatus for generating a multi-wavelength pulse train use a technique referred to as time-lens compression. The time-lens is formed of a phase modulator in series with a dispersion element. In addition to pulse compression, this time-lens simultaneously displaces the pulses according to their center wavelengths, resulting in a temporally evenly spaced multi-wavelength pulse train. An aberration correction technique, based on the temporal analog of a spatial correction lens, can also be employed improve the quality of the compressed pulses. Through use of CW DFB lasers and electrooptic phase modulators, the all-fiber system allows complete tunability of temporal spacing, spectral profile and repetition rate.

Abstract: A programmable, ultrafast optical delay line based on reversible frequency conversion uses a time-prism pair and no moving parts. A first electro-optic phase modulator acting as a first time-prism shifts the frequency of an incoming pulse train. The pulse train passes through a dispersion element, such as a dispersive fiber, which delays the pulse train by an amount that is directly proportional to the magnitude of the frequency shift, which in turn is proportional to the magnitude of the phase modulator drive voltage. A second electro-optic phase modulator is driven ? out of phase to the first modulator and restores the frequency of the delayed pulse train to the original frequency of the incoming pulse train. To reduce pulse broadening effects and enhance performance further, soliton propagation inducing elements can be employed between the time-prisms.

Abstract: Solid and liquid pesticidal concentrate and spray compositions are described which exhibit enhanced efficacy due to the addition thereto of a compound which increases EPSPS enzyme inhibition by the pesticide, cell membrane permeability, or expression of hydroxyproline-rich glycoproteins.

Abstract: A laser scanning microscope produces molecular excitation in a target material by simultaneous absorption of three or more photons to thereby provide intrinsic three-dimensional resolution. Fluorophores having single photon absorption in the short (ultraviolet or visible) wavelength range are excited by a beam of strongly focused subpicosecond pulses of laser light of relatively long (red or infrared) wavelength range. The fluorophores absorb at about one third, one fourth or even smaller fraction of the laser wavelength to produce fluorescent images of living cells and other microscopic objects. The fluorescent emission from the fluorophores increases cubicly, quarticly or even higher power law with the excitation intensity so that by focusing the laser light, fluorescence as well as photobleaching are confined to the vicinity of the focal plane.

Abstract: A laser scanning microscope produces molecular excitation in a target material by simultaneous absorption of three or more photons to thereby provide intrinsic three-dimensional resolution. Fluorophores having single photon absorption in the short (ultraviolet or visible) wavelength range are excited by a beam of strongly focused subpicosecond pulses of laser light of relatively long (red or infrared) wavelength range. The fluorophores absorb at about one third, one fourth or an even smaller fraction of the laser wavelength to produce fluorescent images of living cells and other microscopic objects. The fluorescent emission from the fluorophores increases cubicly, quarticly or even higher power law with the excitation intensity so that by focusing the laser light, fluorescence as well as photobleaching are confined to the vicinity of the focal plane.