Abstract: A laser communication system includes a first laser to generate a laser signal with femtosecond pulses. A first grating spectrally disperses the femtosecond pulses of the laser signal. A modulator converts the femtosecond pulses of the laser signal into coded words. A second grating spectrally recombines the coded words of the laser signal. A first telescope launches the laser signal. A second telescope receives the laser signal. A second laser generates a set of reference pulses. A non-linear crystal combines the set of reference pulses and the laser signal so as to create an output signal only when the laser signal and the reference pulses temporally coincide. A detector records the output.

Abstract: An apparatus and method for enabling the creation of multiple extended conduction paths in the atmosphere including a chirped-pulse amplification laser system having a high peak-power laser capable of transmitting through the atmosphere a high-peak power ultrashort laser pulse. The laser pulse is configured to have a rough spacial profile and is of sufficient energy to create multiple electrically conductive ionized channels in the atmosphere.

Abstract: The present invention provides an arrangement for analyzing or reconstructing incoming pulses of electromagnetic energy in which there is detected (a) the spectral amplitude of at least one pulse and (b) the phase shifts of portions of the pulse with respect to a non-phase shifted portion, and applying an inverse Fourier transform to the detected energy thereby producing the temporal profile of the pulse.

Abstract: An arrangement for discharge of electricity or lightning in the atmosphere to prevent formation of space charges that would reduce the strength of electric fields therein by transmitting through a path in the atmosphere one or more first leaser pulses of wavelength essentially within the ultraviolet range and of duration sufficient to create an electrically conductive ionized channel in the atmosphere and simultaneously transmit in said path one or more second laser pulses of longer wavelength than the ultraviolet pulses to maintain the conductivity of the channel for a time long enough for lightning to occur therein.

Abstract: An improvement for a ring laser gyro employs insertion of a wavefront conjugating coupling element inside a laser cavity to reduce the lock-in threshold and to reduce the imbalance between the amplitudes of the opposite direction traveling waves (ODTW) in homogeneously broadened rotating ring lasers.

Abstract: A method of irradiating a collection of particles by ultrashort pulses of light with isotopic selectivity having application in various methods of isotope separation (two step photoionization, photochemical separation or radiation pressure). In particular there is disclosed a method and apparatus for the efficient acceleration and collection of particles by means of radiation pressure, exemplified by separating a preselected isotope species from a gaseous mixture of isotopes. The gaseous mixture is irradiated with ultrashort, repetitious pulses of coherent light, each pulse having an intensity, frequency and duration selected to create momentum changes in the preselected gaseous isotope whereby to spatially isolate the isotope. Preferably, irradiation is carried out in the cavity of a mode-locked laser into which the gaseous mixture is injected.