Abstract: A diffraction limited working beam at a given frequency is amplified without degrading its diffraction limited quality by diverting a minor portion of the beam as a probe beam, and amplifying the remaining portion of the working beam with a high power pump beam at a different wavelength. The amplification takes place in a host medium that has a rare earth dopant with an energy transition from the pump beam's wavelength to the wavelength of the working beam. The resulting amplified working beam is non-diffraction limited. The probe beam is frequency modulated and coupled with the amplified working beam in a second host medium that also has a rare earth dopant. Energy is transferred from the amplified working beam to the modulated probe beam through a resonant energy transfer in the second host medium, producing an amplified output beam at the working beam frequency that retains the diffraction limited quality of the probe beam.

Abstract: When an optical signal is modulated at two modulation frequencies, third order intermodulation distortion (IMD) is eliminated by inducing an out-of-phase signal that is complementary to the modulated signal, and cross-coupling the two signals with each other to remove the third order terms. An optical beam in a first waveguide is electro-optically modulated and coupled with a second waveguide to induce the out-of-phase complementary beam therein. A second optical coupler is provided that cross-couples the beams in the two waveguides downstream from the first optical coupler. The optical coupling coefficients, the coupler lengths, and the differential between the optical propagation coefficients of the two waveguides within the first coupler are selected empirically to substantially negate third order IMD. The differential in propagation coefficients is established by the DC bias of the modulation signal.

Abstract: A molecular beam epitaxy (MBE) growth method and apparatus is disclosed which achieves a significantly improved sticking coefficient for materials like Hg upon a substrate, and thus a higher efficiency. A highly ionized, low pressure plasma is formed consisting of a mixture of ions of one substance of a compound to be epitaxially grown, neutral particles of the substance and electrons, and also preferably both ionization and excitation radiation. The plasma is directed onto a substrate together with a flux of the other substance in the compound; the flux can be in the form of either a vapor, or a second plasma. Radiation assisted epitaxial growth for Hg compounds in which ionization and excitation radiation are formed from Hg vapor and used to assist epitaxial growth with neutral Hg particles is also described. The plasma is formed in a special discharge chamber having a hollow cathode with an emissive-mix-free cathode insert.

Abstract: A molecular beam epitaxy (MBE) growth method and apparatus is disclosed which achieves a significantly improved sticking coefficient for materials like Hg upon a substrate, and thus a higher efficiency. A highly ionized, low pressure plasma is formed consisting of a mixture of ions of one substance of a compound to be epitaxially grown, neutral particles of the substance and electrons, and also preferably both ionization and excitation radiation. The plasma is directed onto a substrate together with a flux of the other substance in the compound; the flux can be in the form of either a vapor, or a second plasma. Radiation assisted epitaxial growth for Hg compounds in which ionization and excitation radiation are formed from Hg vapor and used to assist epitaxial growth with neutral Hg particles is also described. The plasma is formed in a special discharge chamber having a hollow cathode with an emissive-mix-free cathode insert.

Abstract: A type II staggered alignment multiple quantum well (MQW) is integrated into a laser cavity to implement an active Q-switched device. The MQW initially absorbs and stores energy to prevent the device from lasing. In response to an applied electric field, the MQW experiences a sudden charged carrier population inversion and emits a strong, short duration pulse having a directionality conincident with that of the beam within the lasing cavity. A generalization of the invention involves optical amplification in which photon energy is first stored in a type II staggered alignment MQW, followed by the simultaneous application of an electric field and an optical beam to the MQW, such that the stored energy is released in a sudden pulse which is amplified with respect to the applied optical beam, and is co-directional with the applied beam.