Abstract: Sterically stabilized second-order nonlinear optical chromophores and devices incorporating the same are embodied in a variety of chromophore materials. An exemplary preferred chromophore includes an electron donor group, an electron acceptor group and a bridge structure therebetween, with the electron acceptor group being double bonded to the bridge structure. In a preferred embodiment, the bridge structure also includes at least one bulky side group. Another exemplary preferred chromophore includes an electron donor group, an electron acceptor group and a ring-locked bridge structure between the electron donor group and the electron acceptor group. The bridge structure comprises, for example, two protected alicyclic rings or ring-locked trienone. Another exemplary preferred chromophore includes an electron donor group, a ring-locked tricyano electron acceptor group, and a bridge structure therebetween. In a preferred embodiment, the electron acceptor group comprises an isophorone structure.

Abstract: Second-order nonlinear optical (NLO) polyene-based chromophores sterically stabilized with a dioxine ring and NLO chromophores containing bithiophene derivatives, and devices incorporating the same, are disclosed. An exemplary preferred chromophore includes an aminophenyl electron donor group and a dioxine-containing bridge structure. Another exemplary preferred chromophore includes a ring-locked bridge structure with a dioxine unit and a bithiophene unit. Another exemplary preferred chromophore includes a bridge structure with a bithiophene unit and an isophorone-derived cyclohexene unit.

Abstract: Sterically stabilized polyene-bridged second-order nonlinear chromophores and devices incorporating the same are embodied in a variety of chromophore materials, and particularly in chromophore materials are configured within an oxygen-free operating environment. An exemplary preferred chromophore includes an electron donor group, an electron acceptor group and a &pgr;-conjugate bridge structure therebetween. The bridge is a polyene structure having a five-, six- or seven-membered ring to lock one carbon-carbon double bond. The bridge contains an unlocked conjugate diene unit which connects the bridge ring and the acceptor. Another exemplary preferred chromophore includes an electron donor group, an electron acceptor group and a ring-locked bridge structure between the electron donor group and the electron acceptor group. The bridge structure includes a fused double-or triple-ring structure which functions to lock two or three double bonds.

Abstract: A new class of high hyperpolarizability organic chromophores and a process for synthesizing the same. The chromophores incorporate at least one organic substituent and are formed in consideration of molecular shapes and a spatial anisotropy of intermolecular interactions. The chromophores are processed into hardened material lattices to lock-in poling induced electric-optic activity. Preferred organic substituents are alkyl, aryl, and isophorone groups. A composite including the organic chromophore, in a preferred embodiment, includes a polymer such as a poly(methylmethacrylate), polyimide, polyamic acid, polystyrene, polycarbonate or polyurethane. The optimized chromophores result in hardened electro-optic polymers suitable for electro-optic modulators and other devices such as optical switches. These modulators can be configured to work at high frequencies and in arrays for applications in communications and network connections.

Abstract: Multiple quantum wells within an impact avalanche transit time device (IMPATT) utilizing a plurality of gallium arsenide/aluminum gallium arsenide heterojunctions are used to provide a high power, high frequency, high efficiency device operating at 50 GHz and up. The multiple quantum wells defined by the heterojunctions between pairs of gallium arsenide quantum wells and aluminum gallium arsenide barrier layers improves the nonlinearity of the avalanche process within the gallium arsenide quantum wells and reduces the ionization rate saturation limitations. Optical injection locking of the current through the IMPATT device is achieved by irradiating the active layer of the IMPATT device with modulated laser light.

Abstract: A millimeter wave power generator combines two laser beams, tuning the beat frequency to the desired millimeter wave value with an opposing pair of millimeter wave cavities. The combined beam is diffracted onto a plurality of externally powered, modulation doped field effect photodetectors (MDFEPs). A plurality of antennas is provided, one between each pair of adjoining MDFEPs. The antennas are parallel, and each is driven by the MDFEPs at its ends. The back propagating millimeter wave radiation is reflected forward by a wire grid parallel to the antennas. The grid is situated between the diffractor and the MDFEPs, and is spatially tuned to constructively interfere the reflected back propagating with the forward propagating millimeter wave radiation.

Abstract: A near millimeter bistable device having a source of electromagnetic radiation in optical alignment with a variable reflecting means in the form of a Schottky barrier diode corner cube assembly. Interposed between the radiation source and the variable reflecting means is a beam splitter which reflects a beam of energy from the variable reflecting means through another beam splitter to a detector. The voltage produced by the detector is fed through a feedback circuit back to the variable reflecting means in order to vary the reflectivity thereof. In this manner the output of the device emanating from the other beam splitter has two stable conditions, one of relatively high output power and one of relatively low output power.

Abstract: A modulator and tunable oscillator capable of reliable operation in the near millimeter wavelength region. The modulator is made up of a pair of reflectors and a beamsplitter interposed therebetween with one of the reflectors having variable reflectivity. In addition, the reflectors are spaced apart a preselected distance such that a resonant condition is achieved with respect to an incoming beam of near millimeter wavelength radiation. By applying a signal to the variable reflector a beam of radiant energy is generated at a wavelength at which a non-resonant condition is achieved between the reflectors. This generated beam of radiation is directed out of the modulator by the beamsplitter. The oscillator utilizes the same elements as the modulator and in addition incorporates therein an additional beam splitter and a detector as well as a feedback circuit between the detector and variable reflector.

Abstract: An optically pumped submillimeter laser system having a laser cavity which contains therein a diffraction grating. The diffraction grating is used simultaneously as an efficient first order diffractor for coupling in the short wavelength pump radiation and as a zero order or highly reflecting plane mirror for the production of an output of (long wavelength) submillimeter wavelength.