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Quantum Electronics, IEEE Journal of

Issue 6 • Date Jun 1995

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Displaying Results 1 - 25 of 25
  • A new photoreceiver concept using InGaAs-transferred-electron devices

    Publication Year: 1995 , Page(s): 1152 - 1157
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (480 KB)  

    A new optical receiver is proposed incorporating an InGaAs-transferred-electron device with Schottky gate-electrode (STED) and an InGaAs-metal-semiconductor-metal detector (MSM). This photoreceiver is applicable to the detection of digital, intensity modulated signals and can be integrated on an InP-substrate. The monolithically integrated circuit has been fabricated. Both the integrated STED and the MSM detector has been characterized. From the measurements the receiver can be expected to offer high current gain and inherent pulse shaping. Based on experiments the sensitivity and the gain of the photoreceiver as a function of the bit-rate has been calculated View full abstract»

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  • Analysis of FM and AM responses of a tunable three-electrode DBR laser diode

    Publication Year: 1995 , Page(s): 1009 - 1014
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (416 KB)  

    Starting with the wave propagation equation, neglecting spatial and spectral hole-burning effects, and using a solving method based on the Green's function, the rate equations are derived for a multielectrode laser. By applying them to a three-electrode DBR laser, tunability and linewidth performance are evaluated, and the modulation characteristics such as the amplitude response and the frequency response are analyzed. It is shown that amplitude modulation can be completely suppressed, and at the same time, a pure frequency modulation obtained if currents are related by an adequate equation. Since this laser diode has many advantages such as a wide wavelength tunability and a narrow spectral linewidth, it will be suitable as a lightwave oscillator or transmitter in future communication systems View full abstract»

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  • Modeling and experimental observation of parametric fluorescence in periodically poled lithium niobate waveguides

    Publication Year: 1995 , Page(s): 997 - 1008
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (908 KB)  

    We present a theoretical and experimental study of parametric generation in a guided wave quasi-phase-matched configuration. A numerical model taking into account inverted domain shape, electrooptic and photorefractive effects, as well as waveguide profiles allows calculation of the observed phase matching curves. The observed parametric fluorescence efficiencies can be explained by assuming a slight reduction of nonlinear coefficient and/or a partial degradation of the nonlinear grating. Optimization of the grating depth profile would permit room temperature parametric oscillation using pump wavelengths and powers attainable with diode lasers View full abstract»

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  • Refractive index modulation based on excitonic effects in GaInAs-InP coupled asymmetric quantum wells

    Publication Year: 1995 , Page(s): 988 - 996
    Cited by:  Papers (24)  |  Patents (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (728 KB)  

    The effect of excitons in GaInAs-InP coupled asymmetric quantum wells on the refractive index modulation, is analyzed numerically using a model based on the effective mass approximation. It is shown that two coupled quantum wells brought in resonance by an applied electric field will, due to the reduction in the exciton oscillator strengths, have a modulation of the refractive index which is more than one order of magnitude larger than in a similar quantum well structure based on the quantum confined Stark effect, but with no coupling between the quantum wells. Calculations show that combining this strong electrorefractive effect with self-photo-induced modulation in a biased-pin-diode modulator configuration, results in an optical nonlinearity with a figure of merit of 20 cm3/J at a wavelength of 1.55 μm. This value is large compared to optical nonlinearities originating from band edge resonance effects in III-V semiconductor materials View full abstract»

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  • A 70-period high-precision microwiggler for free electron lasers

    Publication Year: 1995 , Page(s): 1158 - 1165
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (676 KB)  

    We have designed, constructed, and operated a 70-period microwiggler for free electrons lasers (FEL's). The device is a pulsed ferromagnetic-core electromagnet with a period of 8.8 mm, which generates an on-axis peak magnetic field of 4.2 kG. The pulses, of 0.5 ms duration, are generated at a rate of 0.5 Hz. Each field peak is independently tunable. We employed a novel tuning regimen to reduce the RMS spread in the peak amplitudes to 0.12%, the lowest value thus far attained in a sub-cm-period periodic magnetic field View full abstract»

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  • Repetitively pulsed, 70-J photolytic iodine laser with excellent optical and long/reliable operation

    Publication Year: 1995 , Page(s): 1069 - 1081
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1064 KB)  

    The performance of a repetitively pulsed, 70 joule, closed cycle 1.3 μM photolytic atomic iodine laser with excellent beam quality (BQ=1.15) is presented. This BQ was exhibited in the fundamental mode from a M=3.1 confocal unstable resonator at a 0.5 Hz repetition rate. A closed cycle scrubber/laser fuel system consisting of a condensative-evaporative section, two Cu wool I2 reactor regions, and an internal turbo-blower enabled the laser to operate very reliably with low maintenance. The fuel system provided C3F 7I gas at 10-60 torr absent of the photolytic quenching by-product I2. Using a turbo-molecular blower longitudinal flow velocities greater than 10 m/s were achieved through the 150 cm long by 7.5×7.5 cm2 cross sectional photolytic iodine gain region. In addition to the high laser output and excellent BQ, the resulting 8-12 μs laser pulse had a coherence length greater than 45 meters and polarization extinction ratio better than 100:1. Projections from this pulsed photolytic atomic iodine laser technology to larger energies, higher repetition rates, and variable pulse widths are discussed View full abstract»

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  • Internal Q-switching in semiconductor lasers: high intensity pulses of the picosecond range and the spectral peculiarities

    Publication Year: 1995 , Page(s): 1015 - 1021
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (672 KB)  

    Optical pulses of ~100 ps duration, and ~102 W power were obtained from the industrial single heterostructure lasers with a standard pulse generation power of ~10 W in the internal Q-switching mode. Temporal and spectral analyses allow three components to be distinguished in the laser optical pulses: ordinary delayed pulses of large duration at energies considerably lower than the energy gap, short optical pulses caused by the gain-switching effect at higher energies, and short optical pulses at the end of the current pulse (Q-switching mode) at the highest energies. A model is proposed involving band tail states as a saturable absorber causing large delays View full abstract»

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  • Two-photon optical bistability in polar molecules: vibrational coupling effects

    Publication Year: 1995 , Page(s): 1088 - 1097
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (656 KB)  

    Single-beam two-photon optical bistability in a two-level system where the levels have unequal electric dipole moments is analyzed theoretically. By means of unitary transformations the system is transformed into a two-level nonpolar system with a field-dependent effective transition dipole moment. Two-photon optical bistability is found to be favored as the difference between the dipole moments grows. When the excited electronic system is coupled to a vibrational normal mode of the nuclei, the susceptibility becomes three-valued and consequently a different type of optical bistability appears, which can coexists with the previous one View full abstract»

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  • Numerical studies on soliton propagation in dielectric media by the nonlinear Lorentz computational model

    Publication Year: 1995 , Page(s): 1098 - 1106
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (504 KB)  

    Soliton propagation in the dielectric media has been simulated by using the nonlinear Lorentz computational model, which was recently developed to study the propagation of electromagnetic waves in a linear and a nonlinear dielectric. The model is constructed by combining a microscopic model used in the semi-classical approximation for dielectric media and the particle model developed for plasma simulations. The carrier wave frequency is retained in the simulation so that not only the envelope of the soliton but also its phase can be followed in time. It is shown that the model may be useful for studying pulse propagation in the dielectric media View full abstract»

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  • Effect of the nonlinear gain in the visibility of a semiconductor laser with incoherent feedback in the coherence collapsed regime

    Publication Year: 1995 , Page(s): 1022 - 1028
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (516 KB)  

    We study the influence of the gain saturation parameter ε on the visibility of a semiconductor laser subject to optical feedback in the coherence collapsed state. The experimental measurements are compared with the results obtained integrating the Lang and Kobayashi equations and a good agreement is found varying the amount of feedback and using different values of ε. The analysis reveals that there is a best value of ε that fits the experimental measurements and that, for this value of ε, the values of γ found are in the expected relation with the attenuation used experimentally View full abstract»

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  • Dynamics of monolithic passively mode-locked semiconductor lasers

    Publication Year: 1995 , Page(s): 1051 - 1058
    Cited by:  Papers (29)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (676 KB)  

    Monolithic colliding pulse mode-locking (CPM) in semiconductor lasers is compared with self colliding pulse mode-locking (SCPM) through a large signal dynamic computer model which incorporates most of the significant features of semiconductor lasers. These include gain saturation, spontaneous emission, the gain-frequency relation, and the line-width enhancement factor. This new model replicates many of the published experimental results and also gives additional insight into the internal operation of the device. In particular, gain saturation combined with the standing waves created by colliding pulses within the saturable absorber produce a transient gain grating. This is found to have significant effects in locking either the even or the odd modes together in CPM. A performance comparison between CPM and SCPM is completed and some key design parameters of both configurations are explored View full abstract»

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  • Optical frequency conversions in nonlinear medium with periodically modulated linear and nonlinear optical parameters

    Publication Year: 1995 , Page(s): 981 - 987
    Cited by:  Papers (17)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (548 KB)  

    A new method considering both linear and nonlinear optical parameter modulation and propagation loss is proposed to treat second-order nonlinear optical interactions in nonlinear media having periodic structures. Mathematical expressions are derived for difference frequency generation (DFG) and compared with those for second-harmonic generation (SHG). Wavelength conversions around 1.55 μm, which are very interesting in optical communication systems, are studied for semiconductor DFG devices with periodic structures. Semiconductor (e.g., AlGaAs) DFG devices of standard device lengths (several mm) and pump light intensities (105 kW/cm2) are shown capable of practical level conversion efficiencies (~10%) and extremely wide bandwidths (⩾100 nm). Effects of propagation loss in DFG devices are also examined View full abstract»

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  • Evaluation of the tolerance of asymmetric Fabry-Perot modulators with respect to realistic operating conditions

    Publication Year: 1995 , Page(s): 1140 - 1151
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1088 KB)  

    This paper is concerned with asymmetric Fabry-Perot modulators (AFPM's) that use the electroabsorptive effect in GaAs-AlGaAs multiple quantum wells (MQW) to yield optical modulation. Although these devices may attain excellent peak-performance characteristics, their resonant nature makes them susceptible to variations in manufacture and to the operational conditions and this will ultimately limit their actual practical implementation. We examine in detail the tolerance of an AFPM to concurrent fluctuations of the main parameters that affect the performance, and evaluate the limitations of the current state-of-the-art. Thus we develop a procedure by which the overall tolerance of resonant structures may be realistically calculated, and identify a parameter of merit that enables an optimization in that respect. A number of ways to minimize the effect on the final performance are also addressed View full abstract»

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  • Determination of the thermal lens in solid-state lasers with stable cavities

    Publication Year: 1995 , Page(s): 1082 - 1087
    Cited by:  Papers (11)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (496 KB)  

    A useful method to determine the thermal lens in a thermally loaded material inside a laser resonator under operation is presented. The laser beam emitted is focused with a lens placed exactly at the distance of its focal length behind the output mirror. For stable spherical resonators this focusing is not astigmatic even for an astigmatic cavity. This fact is used to experimentally determine the thermal lens including the beam quality factor (beam propagation factor) M2 of the laser beam. Measurements are presented for an end-pumped rod and a longitudinally pumped slab laser serving as an example for an astigmatic cavity View full abstract»

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  • Derivation of gain spectra of laser diodes from spontaneous emission measurements

    Publication Year: 1995 , Page(s): 1047 - 1050
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (368 KB)  

    The use of detailed balance relationships between absorption and emission to obtain a gain spectrum from a spontaneous emission spectrum is a relatively easy method of measuring the gain from a semiconductor laser. It has been shown that the usual theoretical gain and emission spectra do not satisfy these relationships casting doubt on the validity of the procedure. We show that this arises from the incorrect implementation of spectral broadening that leads to a situation where the carriers and photons are no longer in thermal equilibrium and the relationship between absorption and gain in the calculations breaks down. We show that with a more exact implementation of spectral broadening thermal equilibrium is preserved and that the relationship between absorption and emission remains valid. We discuss the accuracy of the measurements required to obtain a correct gain spectra View full abstract»

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  • Complete statistical characterization of signal and noise in optically amplified fiber channels

    Publication Year: 1995 , Page(s): 1114 - 1122
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (648 KB)  

    A very simple model is found for phase insensitive laser amplification. Signal and noise along the active fiber are modeled as marked Poisson processes (corresponding to flows of photon bunches of random size) and are dealt with as independent processes. A probabilistic approach, founded on the theory of birth-and-death processes, enables us to give a simple characterization of the amplifier in terms of the statistics of the random gain, of the time intensity of the ASE (amplified spontaneous emission) noise bunches, and finally of the statistics of their sizes. The theory is limited to the linear amplification range, while is valid also for nonhomogeneous inversion along the active fiber. The model can be easily applied for the evaluation of the statistics of the global gain and of the accumulated ASE noise in optically amplified links View full abstract»

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  • Laser radiation scattering by the optical breakdown plasma

    Publication Year: 1995 , Page(s): 1172 - 1177
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (548 KB)  

    The spatial distribution measurements of laser radiation, scattered in the laser spark, were accomplished for various laser radiation wavelengths (1060, 530, 353, and 265 nm) and various pressures of the gas (air at 10-760 mm Hg). The interference structure of the laser light scattering cone behind the laser spark was observed for the first time. It is proposed to consider the observed structure as a result of interference of the laser radiation, scattered by two or more self-focusing centers in laser spark air plasma. The experimental dependence of the maximal angle of the light scattering on the gas pressure and on the laser radiation wavelength was obtained View full abstract»

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  • Inter-transverse-mode injection locking and subthreshold gain measurements in a CO2 waveguide laser

    Publication Year: 1995 , Page(s): 1064 - 1068
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (376 KB)  

    A higher order CO2 waveguide laser resonator mode has been studied both above and below threshold, by reinjecting a frequency shifted portion of the laser output back into the resonator. The relative reinjected (autodyne) gain profile in the vicinity of the subthreshold transverse mode is shown to shift in frequency, reduce in spectral width, and increase in magnitude as the subthreshold mode is brought nearer to threshold by tilting one of the resonator mirrors. Once above threshold, inter-transverse-mode injection locking has been demonstrated, and close to the locking-point higher order terms from the nonlinear interaction are clearly evident View full abstract»

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  • Study and design of step-index channel waveguide bends with large-angle and low-loss characteristics

    Publication Year: 1995 , Page(s): 1131 - 1139
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (712 KB)  

    By using micro-prisms, improved three-dimensional (3-D) bends of the embedded and buried waveguides of step-index profile are proposed. A simple phase compensation rule for the optimal design of the micro-prism is also presented. Through the simulation of 3-D semivectorial finite-difference beam propagation method, the transmission characteristics of the improved bends are shown to have been enhanced dramatically as compared with those of the conventional ones. Even for a bend angle of as large as 10°, the normalized transmitted power can still be greater than 95%. These results of 3-D bends are then compared with those of the two-dimensional (2-D) ones which are simplified from 3-D structures by the effective index method, and physical explanation of the discrepancy between the 3-D and 2-D results is introduced. The influences of waveguide structures and prism parameters on the transmission characteristics are discussed in detail. Some criteria for the design of large-angle low-loss 3-D improved bends are also accessed View full abstract»

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  • A higher order electron wave propagation method

    Publication Year: 1995 , Page(s): 1107 - 1113
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (464 KB)  

    A finite-difference propagation scheme for simulating electron currents through arbitrary quantum structures is presented in this paper. It is shown that due to the strong interaction of external fields and electrons, the trajectories predicted using higher order propagation operators are a significant improvement over that of lower order schemes, especially in cases where the longitudinal electron momentum is not accurately known. A novel boundary condition based on the popular transparent boundary condition is used for minimizing unphysical reflections off the computation boundaries even in the presence of strong lateral electric fields. The application of this scheme is illustrated through a few examples View full abstract»

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  • Optimization of the optical output in a C-to-C pulsed gas laser

    Publication Year: 1995 , Page(s): 1059 - 1063
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (328 KB)  

    An investigation of the optimum condition for maximum optical output in a C-to-C pulsed gas laser (N2 laser) showed that this condition does not happen when the two capacitances are equal (C 1=C2) as this happens in the “Doubling circuit” case, but when the peaking capacitance obtains a critical value. This behavior is attributed to the electric pumping pulse formed by the temporary loading of the peaking capacitor. This electric pumping pulse increases as the peaking capacitor increases. However, for low values of the peaking capacitor the optical output follows the rise of the electric pumping pulse. On the other hand, for higher values of the peaking capacitor than a critical one, a part of the electric energy arrives at the laser channel after the laser output, while the exploitable electric energy decreases causing reduction of the optical output View full abstract»

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  • Continuous-wave frequency synthesis of a laser diode based on discrete-time negative frequency feedback. I. Experiment

    Publication Year: 1995 , Page(s): 1038 - 1046
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (696 KB)  

    The absolute frequency synthesis of a distributed-feedback (DFB) laser diode (LD) is demonstrated by use of a loss-compensated optical ring circuit with a frequency shifter and a frequency-stabilized master laser system containing an acetylene (13C2H2 ) absorption cell. A lightwave from the master laser is modulated into a pulse and circulated around the ring to shift its frequency in the 0~100 GHz range. A continuous-wave from the DFB LD is mixed with a recirculated pulse with a desirable reference frequency, and their beat frequency is counted in order to obtain the error signal. The absolute frequency of the DFB LD is locked to the reference frequency based on discrete-time negative frequency feedback control for the injection current. The accuracy of the absolute frequency was experimentally confirmed to be within a few MHz for an averaging time of 1 s and an operation time of 1 hour View full abstract»

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  • Nonuniform injection current induced unusual chirp behavior of a four-electrode bistable distributed Bragg reflector laser

    Publication Year: 1995 , Page(s): 1029 - 1037
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (704 KB)  

    A complete analysis of the chirp of a four-electrode bistable distributed Bragg reflector laser is given in theory and by experiment. Experimentally, the chirp investigation is realized by a Mach-Zehnder interferometer. In small-signal regime, the modulus and phase of 2β/m, frequency and amplitude modulation index ratio, is measured for different injection currents and shows an unusual behavior against the modulation frequency. A theoretical model including nonuniform injection current shows the same behavior of 2β/m against the modulation frequency and proves that the nonuniform carrier distribution inside the cavity is the origin of the specific behavior. The large-signal analysis provides a study of the instantaneous chirp behavior during optical switching View full abstract»

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  • Optical fiber-polymer guide coupling by a tapered graded index glass guide

    Publication Year: 1995 , Page(s): 1123 - 1130
    Cited by:  Papers (5)  |  Patents (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (668 KB)  

    A new four layer tapered coupler (FLTC) has been studied and tested, able to transfer light efficiently from a monomode fiber to a polymer film guide by means of an auxiliary graded index glass waveguide. A simple theory has been developed to calculate the maximum efficiency of these structures. Experiments have been performed, at λ=1.321 μm, on several FLTC samples, containing K+-Na+ ion-exchanged glass waveguides and spin coated poly-3BCMU films. Insertion losses in the range 3-6.5 dB have been measured, depending on the taper configuration. The agreement between theoretical and experimental data is good, provided that a suitable ripple of the taper profile is assumed. The application of the new coupler to future integrated waveguide systems, including passive glass components and polymer based all optical devices, is assessed View full abstract»

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  • The free-electron laser as a laboratory instrument

    Publication Year: 1995 , Page(s): 1166 - 1171
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (456 KB)  

    A free-electron laser (FEL) with a component cost, including the accelerator, of approximately $300k, has lased at a wavelength of 85 μm with ≈12 ps micropulse duration, achieving a power growth four orders of magnitude greater than the coherent spontaneous emission, and with a small-signal, single-pass gain of 21%. The price is about an order of magnitude less than other FELs for the far infrared, and transforms the device from the role of a national facility to that of a laboratory instrument. Cost reduction was achieved by employing several novel features: a microwave cavity gun for the accelerator, a staggered-array wiggler, and an on-axis hole in the upstream cavity mirror for electron ingress and radiation egress View full abstract»

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Aims & Scope

The IEEE Journal of Quantum Electronics is dedicated to the publication of manuscripts reporting novel experimental or theoretical results in the broad field of the science and technology of quantum electronics..

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Aaron R. Hawkins
Brigham Young University