Showing papers by "Amnon Yariv published in 1980"
TL;DR: In this paper, a nonlinear optical processor using a photorefractive medium Bi12SiO20 and demonstrated that it is capable of convolving and correlating objects with spatial information.
Abstract: We report the application of four‐wave mixing to real‐time image processing. We constructed a nonlinear optical processor using a photorefractive medium Bi12SiO20 and demonstrated that it is capable of convolving and correlating objects with spatial information.
224 citations
TL;DR: The possibility of detecting magnetic fields by a magnetostrictive straining of optical fibers is investigated and the effect of shot noise and the limiting sensitivity are considered.
Abstract: The possibility of detecting magnetic fields by a magnetostrictive straining of optical fibers is investigated. The effect of shot noise and the limiting sensitivity are considered.
153 citations
TL;DR: It is demonstrated theoretically that the distortion-correction property of phase-conjugate beams propagating in reverse through aberrating media is also operative when the indices of refraction of the media depend on the intensity.
Abstract: We demonstrate theoretically that the distortion-correction property of phase-conjugate beams propagating in reverse through aberrating media is also operative when the indices of refraction of the media depend on the intensity. A necessary condition is that the phase-conjugate mirror that generates the reflected beam possess a unity (magnitude) "reflection" coefficient.
136 citations
TL;DR: In this paper, a GaAlAs double-heterostructure laser was integrated with a heterojunction bipolar transistor on a GaAs substrate by means of a mutually compatible structure formed by Be ion implantation.
Abstract: A GaAlAs double-heterostructure laser has been monolithically integrated with a heterojunction bipolar transistor on a GaAs substrate. Integration is achieved by means of a mutually compatible structure formed by Be ion implantation. Typical pulsed threshold currents for the laser are 60 mA, and the transistors have a typical common-emitter current gain of 900.
68 citations
TL;DR: The generation of conjugate wave fronts by degenerate four-wave mixing in the isotropic phase of the nematic substance p-methoxy-benzylidene p-n-butylaniline is reported and the dependence of the nonlinear reflectivity on the pump-wave power and the temperature of the medium is discussed.
Abstract: We report the generation of conjugate wave fronts by degenerate four-wave mixing in the isotropic phase of the nematic substance p-methoxy-benzylidene p-n-butylaniline. The temporal and spatial properties of the conjugate wave fronts are verified. The dependence of the nonlinear reflectivity on the pump-wave power and the temperature of the medium is discussed.
38 citations
TL;DR: In this article, the bond-charge dielectric theory of Phillips and Van Vechten is applied to the calculation of the electro-optic tensor coefficients and the agreement of theoretical predictions with experimental values in the case of zinc blende and wurtzite crystals is very good.
Abstract: The bond-charge dielectric theory of Phillips and Van Vechten is applied to the calculation of the electro-optic tensor coefficients The agreement of the theoretical predictions with experimental values in the case of zinc blende and wurtzite crystals is very good
28 citations
TL;DR: In this article, the authors present an experimental and theoretical study of a self-pulsing (GaAl)As injection laser operating in an external cavity, and they have observed suppression of the selfpulsations when the external cavity is in the range 6
Abstract: We present an experimental and theoretical study of a self‐pulsing (GaAl)As injection laser operating in an external cavity. We have observed suppression of the self‐pulsations when the external cavity is in the range 6
27 citations
TL;DR: In this article, the authors investigated the dependence of the pulsation characteristics on the external cavity length using a saturable absorber model for self-pulsing and non-Pulsing lasers coupled to external cavities.
Abstract: The behavior of self-pulsing and nonpulsing lasers coupled to external cavities is investigated experimentally and theoretically. We investigate the dependence of the pulsation characteristics on the external cavity length using a saturable absorber model for self-pulsing lasers. It was found that quenching of self-pulsation occurs only for a certain limited range of external cavity length, and the frequencies of external-cavity induced pulsations lies within a certain range determined by the coupling coefficient. Small-signal analysis allows these ranges to be derived analytically. Hitherto, complex pulsation phenomena can be explained very intuitively by interpreting the combined laser-external cavity system as a microwave oscillator with a limited gain band and discrete mode structure.
24 citations
TL;DR: In this article, double heterostructure lasers are described in which light is guided by total internal reflection along a dielectric interface formed by the perimeter of an etched mesa.
Abstract: Double heterostructure lasers are described in which light is guided by total internal reflection along a dielectric interface formed by the perimeter of an etched mesa. By means of the crowding effect, injection current is restricted to a narrow strip adjacent to the edge of the mesa. This results in the preferential excitation of optical modes which are localized in the vicinity of the dielectric interface. Both half-ring lasers formed at a single cleaved facet and quarter-ring lasers formed at a cleaved corner were fabricated.
22 citations
TL;DR: In this article, a double heterostructure laser has been fabricated on a semi-insulating GaAs substrate, with threshold currents as low as 15 mA for a cavity length of 100 μm.
Abstract: Be implanted stripe geometry double heterostructure lasers have been fabricated on a semi-insulating GaAs substrate, with threshold currents as low as 15 mA for a cavity length of 100 μm. The laser has been monolithically integrated with a metal-semiconductor field-effect transistor.
19 citations
TL;DR: An exact treatment of the space charge effect in the single-electron analysis of a freeelectron laser is presented to calculate its small-signal gain this paper, where the trajectory of an electron can be solved from a generalized equation which includes a space-charge term.
Abstract: An exact treatment of the space-charge effect in the single-electron analysis of a free-electron laser is presented to calculate its small-signal gain. With the inclusion of the repulsive force between electrons, it is found that the trajectory of an electron can be solved from a generalized equation which includes a space-charge term. The results show the gain is saturated with decreasing growth rate due to high electron density. The radiation frequency is found to increase with the electron density and approach the value at plasma resonance. The condition ωpL/c = π clearly defines the boundary between the noninteracting and the collective regime of an electron beam, where ωp is the plasma frequency, L is the device length, and c is the light velocity in vacuum.
TL;DR: In this paper, double-heterostructure stripe geometry lasers have been fabricated using be ion implantation Pulsed threshold currents as low as 21 mA have been found The light vs current characteristics were kink free up to 10 mW output power and the measured differential quantum efficiency was 45%
Abstract: (GaAl)As double‐heterostructure stripe geometry lasers have been fabricated using Be ion implantation Pulsed threshold currents as low as 21 mA have been found The light‐vs‐current characteristics were kink‐free up to 10 mW output power and the measured differential quantum efficiency was 45%
TL;DR: In this article, nonlinear distortion characteristics of GaAs/GaAlAs injection lasers under analog current modulation were experimentally investigated and it was shown that both fundamental and harmonic responses of a self-pulsing laser is indistinguishable from that of a laser with no R.O. resonance.
Journal Article•
TL;DR: In this article, the electron-field coherent quasi-classical states of a free electron laser were defined and the photon number and electron momentum were given by a Poisson distribution centered on the classical trajectories.
Abstract: Abstract We define electron-field coherent quasi-classical states of a free electron laser. In these states both the photon number and the electron momentum are given by a Poisson distribution centered on the classical trajectories.
TL;DR: In this paper, the characteristics of an optical fiber external resonator in conjunction with (GaAl)As stripe geometry lasers are described, and a model that uses the conventional semiconductor rate equations modified by the addition of saturable electron traps and the effects of the external cavity.
Abstract: The characteristics of an optical fiber external resonator in conjunction with (GaAl)As stripe geometry lasers are described. We have observed a 6–10% reduction in the threshold current and have obtained 150 ps pulses at gigahertz repetition rates. The fiber resonator has also been used to quench self‐pulsations in a (GaAl)As injection laser. In order to explain many of our results we have used a model that uses the conventional semiconductor rate equations modified by the addition of saturable electron traps and the effects of the external cavity. Our results predict many of the self‐locking effects observed in injection lasers operating in an external cavity. Furthermore, the degree of self‐locking will be a strong function of the external cavity length and the density of saturable absorbers.
TL;DR: In this paper, a new type of AlGaAs injection laser was described, which consists of alternating p-and n-type layers of GaAs and AlxGa1−xAs.
Abstract: A new type of AlGaAs injection laser is described. The structure consists of alternating p- and n-type layers of GaAs and AlxGa1−xAs . The electrical mode of operation of the device is that of a Shockley diode (SCR). Optically the device operates as a large optical cavity. Single transverse mode operation was observed with optical cavities larger than 4 µm.
TL;DR: Using a bipolar drive current pulse shape and very low threshold (9 mA) lasers, zero-background pseudorandom optical pulses were generated and detected at a rate of up to 4 Gbit/s without a pattern effect as discussed by the authors.
01 Jan 1980
TL;DR: In this paper, a method for producing ultrashort pulses which employs a combination of electrical and optical pumping was described, which can produce pulses tens of picoseconds in duration.
Abstract: Pulses tens of picoseconds in duration have been produced from semiconductor lasers both by injection of short current pulses [1] and by mode-locking [2, 3]. Below we describe a method for producing ultrashort pulses which employs a combination of electrical and optical pumping.
TL;DR: In this paper, a double-heterostructure AlGaAs laser with an embedded optical waveguide has been developed, which exhibits operation in a single spatial and longitudinal mode, has differential quantum efficiencies exceeding 45%, and a characteristic temperature of 175° C.
Abstract: A new type of strip-geometry AlGaAs double-heterostructure laser with an embedded optical waveguide has been developed. The new structure is fabricated using a single step of epitaxial growth. Lasers with threshold currents as low as 9.5 mA (150 µm long) were obtained. These lasers exhibit operation in a single spatial and longitudinal mode, have differential quantum efficiencies exceeding 45%, and a characteristic temperature of 175° C. They emit more than 12 mW/facet of optical power without any kinks.
TL;DR: The interaction between the electrons and the radiation in a free-electron laser leads to a shift and a spread of the electron velocity distribution that can be increased through introduction of an adjustable drift distance between two identical wigglers.
Abstract: The interaction between the electrons and the radiation in a free-electron laser leads to a shift and a spread of the electron velocity distribution. The electron dynamics of a two-element system are studied in the small signal region. It is found that the efficiency and gain can be increased through introduction of an adjustable drift distance between two identical wigglers.