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Showing papers in "IEEE Journal of Quantum Electronics in 1979"



Journal Article
TL;DR: In this paper, the subject of quantum electrodynamics is presented in a new form, which may be dealt with in two ways: using redundant variables and using a direct physical interpretation.
Abstract: THE subject of quantum electrodynamics is extremely difficult, even for the case of a single electron. The usual method of solving the corresponding wave equation leads to divergent integrals. To avoid these, Prof. P. A. M. Dirac* uses the method of redundant variables. This does not abolish the difficulty, but presents it in a new form, which may be dealt with in two ways. The first of these needs only comparatively simple mathematics and is directly connected with an elegant general scheme, but unfortunately its wave functions apply only to a hypothetical world and so its physical interpretation is indirect. The second way has the advantage of a direct physical interpretation, but the mathematics is so complicated that it has not yet been solved even for what appears to be the simplest possible case. Both methods seem worth further study, failing the discovery of a third which would combine the advantages of both.

1,398 citations


Journal ArticleDOI
TL;DR: In this paper, the spontaneous emission factor of planar stripe laser with narrow stripe is calculated and it is shown that spontaneous emission is approximately proportional to the solid angle of laser radiation and nearly independent of transverse active layer dimensions.
Abstract: The fraction of spontaneous emission going into an oscillating laser mode has been calculated. It is shown that this fraction strongly depends on the strength of astigmatism in the laser output beam. Therefore the spontaneous emission factor in planar stripe lasers with narrow stripe is in the order of 10-4and by one order of magnitude larger than in injection lasers with a comparable active layer volume and with a built-in index waveguide. It is shown that the spontaneous emission factor is approximately proportional to the solid angle of laser radiation and nearly independent of the transverse active layer dimensions. Owing to the large spontaneous emission factor, the spectral width of narrow planar stripe lasers is significantly broader compared to narrow stripe lasers with a built-in index waveguide. In addition the large spontaneous emission coefficient also yields a much stronger damping of relaxation oscillations.

474 citations


Journal ArticleDOI
TL;DR: In this article, a complete quantum generalization of microwave mixer theory is constructed for nonlinear single-particle tunnel junctions, which represents a unification of the concepts used to describe these "classical" resistive mixers with the language of photon detection.
Abstract: A complete quantum generalization of microwave mixer theory is constructed for nonlinear single-particle tunnel junctions. The result represents a unification of the concepts used to describe these "classical" resistive mixers with the language of photon detection. Tunneling devices are predicted to undergo a transition from energy detectors to photon counters when operated at frequencies where the photon energy becomes comparable to the voltage scale of the dc nonlinearity. The small-signal video current response is found to approach one electron for each photon absorbed at high frequencies. In a heterodyne receiver, sufficiently nonlinear tunnel junctions are predicted to be capable of achieving the fundamental quantum noise limit for sensitivity in the detection of electromagnetic radiation. The theory presented here thus provides a framework for systematically extending the techniques of quantum electronics to considerably lower frequencies than are currently being exploited. Recent measurements of heterodyne mixer performance using superconductive tunneling devices are already beginning to approach quantum limited results at microwave and millimeter wave frequencies. Eventual application of tunnel barriers as photon detectors in the submillimeter and infrared spectral regions also appears to be possible, and the fast response times of such devices could give them an advantage over photoconductors even at the higher frequencies. The development of suitable nonlinear tunnel junctions contains the potential to bridge the present gap in quantum detectors between the infrared photon devices and microwave masers.

436 citations


Journal ArticleDOI
TL;DR: In this article, a detailed study of the optimum design parameters for the LiNbO 3 parametric oscillator is presented, considering practical factors that limit OPO performance such as laser beam quality and crystal damage mechanisms.
Abstract: This paper presents a detailed study of the optimum design parameters for the LiNbO 3 parametric oscillator. Theoretical and experimental studies of the optical parametric oscillator (OPO) threshold parameters and of linewidth control are presented. Consideration is given to practical factors that limit OPO performance such as laser beam quality and crystal damage mechanisms. In addition, stable single axial mode operation is reported.

431 citations


Journal ArticleDOI
Rogers Hall Stolen1
TL;DR: Raman and Brillouin gains in fibers are a factor of 2 higher if linear polarization is maintained as mentioned in this paper.Birefringent single-mode fibers are used to demonstrate this gain difference.
Abstract: Raman and Brillouin gains in fibers are a factor of 2 higher if linear polarization is maintained. Birefringent single-mode fibers are used to demonstrate this gain difference. Threshold powers of 200 mW have been achieved in Raman oscillators.

285 citations


Journal ArticleDOI
TL;DR: In this article, a detailed theoretical and experimental study of optical parametric amplification is presented, which is an important method for power generation in the optical and infrared spectral range, with high conversion efficiency and wide tuning range.
Abstract: This paper presents a detailed theoretical and experimental study of optical parametric amplification. Experimental measurements in KD*P pumped at 354.7 nm and LiNbO 3 pumped at 1064 nm by a Q -switched Nd:YAG source are in excellent agreement with theory. The large gains, high conversion efficiency, and wide tuning range make optical parametric amplification an important method for power generation in the optical and infrared spectral range.

256 citations


Journal ArticleDOI
H. Taylor1
TL;DR: A design for an optical analog-to-digital converter using channel waveguide modulators is described, and the implications of signal sampling with a repetitively pulsed light source are discussed.
Abstract: A design for an optical analog-to-digital converter using channel waveguide modulators is described. Optical and electrical power requirements and factors which limit the speed of operation are analyzed, and the implications of signal sampling with a repetitively pulsed light source are discussed.

233 citations


Journal ArticleDOI
TL;DR: In this paper, the backward Raman amplifier is shown to be a promising candidate for this application and gain, saturation, and limits to amplifier performance are described, and design tradeoffs and possible techniques for further improving the performance of such amplifiers are discussed.
Abstract: Application of efficient ultraviolet excimer lasers such as the 248 nm KrF laser to laser fusion requires that long laser pulses be efficiently converted to short pulses at high intensity. The backward Raman amplifier is shown to be a promising candidate for this application. Gain, saturation, and limits to amplifier performance are described. It is shown that pump beams of poor spatial quality may be converted to output beams of high spatial quality. Several common gaseous vibrational Raman scatterers are discussed, and it is shown that a simple KrF-pumped backward Raman amplifier using methane at atmospheric pressure will have a saturation fluence near 1 J/cm2and can produce an output five times as intense as the pump in a ten times shorter pulse with an efficiency of about 50 percent. Design tradeoffs and possible techniques for further improving the performance of such amplifiers are discussed.

190 citations


Journal ArticleDOI
TL;DR: In this paper, the authors investigated the origin, qualitative, and quantitative properties of low frequency noise appearing in the light output of the laser diode, which is strongly coupled to optical fibers.
Abstract: This paper describes the theoretical investigation of the origin, qualitative, and quantitative properties of the low frequency noise appearing in the light output of the laser diode, which is strongly coupled to optical fibers. This kind of noise has caused serious problems for reliable optical communications, especially for analog-modulation systems. It is shown that there are two different phenomena which generate such noise. One of them is the double cavity state, and the other is the external light injection state. The cause of our noise considered in the double cavity state is the phase variation due to the variation of the equivalent length between the laser and the reflection point generated by mechanical vibrations. On the other hand, the cause in the external light injection state is the random generations of locking and unlocking states due to the frequency variation (or mode jumping) caused by the variation of the internal temperature of the laser diode. We conclude from our theory that an effective method to reduce such noise is to operate the laser diode at well above the threshold current. The complete elimination will be attained by use of the optical isolator inserted between the laser diode and the transmission lines.

158 citations


Journal ArticleDOI
TL;DR: In this article, an analysis of resonator properties for a cavity bounded by a phase conjugate mirror, which is generated by a degenerate four-wave nonlinear optical interaction, is presented.
Abstract: We present an analysis of resonator properties for a cavity bounded by a phase conjugate mirror, which is generated by a degenerate four-wave nonlinear optical interaction. Using a ray matrix formalism to describe the conjugate mirror, resonator stability conditions are derived. Longitudinal and transverse mode characteristics are discussed. Results are compared with an experiment where laser oscillation was observed at 6943 A using carbon disulfide as the nonlinear interacting medium comprising the phase conjugate mirror.

Journal ArticleDOI
TL;DR: The performance of urea as a nonlinear optical crystal for phase-matched second-harmonic generation and sum-frequency mixing in the UV was reported in this paper, where the nonlinear coefficient of Urea was measured and found to be 2.5 times that of ADP.
Abstract: The performance of urea as a new nonlinear optical crystal for phase-matched second-harmonic generation and sum-frequency mixing in the UV is reported. Tunable radiation down to 229 nm was obtained. In particular, efficient doubling at room temperature of CW argon laser lines from 488 to 528 nm was achieved. The nonlinear coefficient of urea was measured and found to be 2.5 times that of ADP. Angle tuning curves for type II SHG, several type II frequency mixing schemes, temperature tuning data, and comparison to other nonlinear materials are presented. More accurate Sellmeier constants were also obtained using the measured angle tuning curve for type I SHG.

Journal ArticleDOI
TL;DR: In this article, the dispersion characteristics of Ar, Kr, and Xe up to their first ionization levels were determined and the spectral regions in the VUV where these gases exhibit negative dispersion and so can be efficiently used for frequency tripling.
Abstract: Using experimentally determined oscillator strengths and photoionization cross-sectional data, we compute the dispersion characteristics of Ar, Kr, and Xe up to their first ionization levels and determine the spectral regions in the VUV where these gases exhibit negative dispersion and so can be efficiently used for frequency tripling. We then investigate the bandwidths over which efficient tripling can be achieved in phase-matched gas mixtures. The bandwidth is limited by the rapidly varying dispersion in the vicinity of resonance transitions in the gases. In particular, we look at the case of frequency tripling 3647 A radiation to 1215.7 A (hydrogen Lyman-α) and show, that for fundamental wavelength bandwidths as narrow as 1 A, the rapid change in refractive index with wavelength can preclude phase matching over the entire bandwidth of the radiation.

Journal ArticleDOI
TL;DR: In this paper, a three-level model for homonuclear diatomic (dimer) laser systems is presented, where the forward direction is strongly favored and in a ring laser system spontaneous unidirectional oscillation is obtained.
Abstract: Bound-bound electronic transitions in simple molecules are generally suited to realize efficient multiline laser oscillation in the visible and ultraviolet spectral region. By means of optical excitation with argon and krypton lasers, CW laser oscillation could be obtained for various homonuclear diatomic (dimer) molecules such as Li 2 , Na 2 , K 2 , Bi 2 , S 2 , Te 2 , and I 2 , with emission of several hundred laser lines in the spectral range of about 400-1350 nm. The principles of these lasers and the general dependence of threshold and output power on temperature, pressure, length of vapor zone, and some other parameters is discussed. To achieve satisfactory CW operation, low quenching losses for the upper laser level population and a sufficiently fast relaxation of the population of the lower laser level are necessary. Under optimum operation conditions, efficiencies up to 15 percent, multiline output powers up to 400 mW, and single line-single frequency output powers up to 200 mW were achieved. These dimer lasers are three-level laser systems. In case of coherent optical excitation, two-photon or Raman-type processes contribute to the amplification process. Due to these mechanisms the forward direction is strongly favored and in a ring laser system spontaneous unidirectional oscillation is obtained. By means of a suitable three-level model, analytical and numerical calculations of gain profiles are performed and compared with experiments. These optically pumped molecular lasers are suited for various spectroscopic and kinetic investigations, for frequency standards or as simple and efficient systems to convert pump laser radiation into other spectral regions.

Journal ArticleDOI
TL;DR: In this article, coupled multiple stripe (CMS) phase-locked, room-temperature diode lasers were used to generate high-power well-collimated beams, which potentially may be electronically scanned in the manner of phased array radar.
Abstract: Experimental and analytic studies of coupled multiple stripe (CMS) phase-locked, room-temperature diode lasers are reported. Such devices generate high-power well-collimated beams, which potentially may be electronically scanned in the manner of phased array radar. For the tested devices with ten conducting 3 μm stripe contacts on centers separated by D and coupled by curved waveguide sections, data from four stripe geometries with D ranging from 10 μm to 27.4 μm are compared and overall optimal characteristics occur for D = 10 \mu m. In that case, threshold current densities are comparable to solid area lasers, differential quantum efficiency is approximately 60 percent, and maximum observed pulsed power per facet is on the order of 1 W.

Journal ArticleDOI
R. Dixon1, W. Joyce1
TL;DR: In this article, a model explaining the origins of sustained oscillations in (Al,Ga)As double-heterostructure lasers is proposed and plausibility arguments of its applicability are given.
Abstract: A model explaining the origins of sustained oscillations in (Al,Ga)As double-heterostructure lasers is proposed and plausibility arguments of its applicability are given. The model relies on saturable-absorber Q -switching to produce the pulsations, with the saturable absorption located near the ends of the laser in regions where surface recombination reduces the injected-carrier density. The sides of the active volume, or defects which cause carrier recombination within the active volume, may also cause such pulsations according to this model.

Journal ArticleDOI
R. Lang1
TL;DR: In this paper, a numerical analysis has been carried out on the behavior of semiconductor injection lasers with a stripe geometry double-heterostructure, taking into account spatial hole-burning and its effect on the waveguiding.
Abstract: A numerical analysis has been carried out on the behavior of semiconductor injection lasers with a stripe geometry double-heterostructure, taking into account spatial hole-burning and its effect on the waveguiding. It is shown that spatial hole-burning, the negative dependence of refractive index eta on the excited carrier density n (d_{eta}/ dn , and the lack of complete symmetry in any real laser structure are the three critical factors responsible for the lateral mode instability leading to such anomalous behaviors these lasers exhibit as a "kink" in the light output versus current relation and the lateral shift in the emission spot. Effects of rigid refractive index and gain-loss profiles built into the laser crystal on the mode stability have been examined, and conditions for kink-free, single lateral mode oscillations have been investigated.

Journal ArticleDOI
TL;DR: In this paper, the effects of length detuning on the synchronously mode-locked CW dye laser were investigated, and it was shown that an increase in cavity length sensitivity with intracavity bandwidth was associated with an asymmetric variation in the pulsewidth and pulse power.
Abstract: We present both theoretical and experimental details on the effects of cavity length deturning of the synchronously mode-locked CW dye laser. The theory predicts an increase in cavity length sensitivity with intracavity bandwidth, and an asymmetric variation in the pulsewidth and pulse power with length detuning from the "matched" position. The predictions are shown to be in close agreement with the results of our experiments on the Rhodamine 6G dye laser.

Journal ArticleDOI
TL;DR: In this article, the dependence of Raman gain upon laser bandwidth was analyzed in terms of a set of coupled mode equations, and it was shown that the Raman gains are independent of pump laser bandwidth within limitations set by dispersion in the RAMan medium.
Abstract: The dependence of Raman gain upon laser bandwidth is analyzed in terms of a set of coupled mode equations. The analysis predicts that the Raman gain is independent of pump laser bandwidth within limitations set by dispersion in the Raman medium. These results are verified for rotational and vibrational transitions in H 2 using a variable bandwidth Nd:YAG laser.

Journal ArticleDOI
TL;DR: A condition for single longitudinal mode operation (SMO) of index-guided injection lasers is given theoretically and supported by experiment in this article, where the transverse higher modes must be cut off by using a narrow-width index-guiding waveguide.
Abstract: A condition for single longitudinal mode operation (SMO, for short) of index-guided injection lasers is given theoretically and supported by experiment. For SMO, the transverse higher modes must be cut off by using a narrow-width index-guiding waveguide. Inclusion of the spontaneous emission into the lasing field must be reduced by using a thinner active region. In terms of the impurity concentration of the active region, the undoped case is the most stable for temperature variation. A heavily doped active region may also produce SMO. The thermal resistance must be reduced to increase temperature stability. MO with a fixed lasing wavelength is experimentally obtained by temperature control up to an injection current of twice threshold.

Journal ArticleDOI
TL;DR: In this paper, the authors investigated the effect of light reflected from an optical system on injection laser output intensity and spectrum, and showed that reflected light from a near-field region causes power deviation and an oscillating wavelength shift.
Abstract: Fluctuations in injection laser output intensity and spectrum caused by light reflected from an optical system are investigated theoretically and experimentally. The theoretical analysis is accomplished by applying the semiclassical theory to an injection laser, and introducing an optical feedback term. It is shown that light reflected from a near-field region causes power deviation and an oscillating wavelength shift. It is also shown that reflected light from a far-field region changes laser light spectrum and introduces frequency noise components in laser output power.

Journal ArticleDOI
TL;DR: In this article, the authors reveal the presence of strong coupling between TE and TM modes in a periodically corrugated optical-waveguide when the wave propagates obliquely with respect to grating vector.
Abstract: By employing a coupled-mode analysis, we reveal the presence of strong coupling between TE and TM modes in a periodically corrugated optical-waveguide when the wave propagates obliquely with respect to grating vector. The evidence of such mode coupling has been obtained by the polarized transmission and reflection experiment; then the measured strengths of coupling among various modes are successfully compared with calculated values. The effect of such coupling on the performance of a frequency demultiplexer is discussed with some preliminary experiments.

Journal ArticleDOI
TL;DR: In this article, broad-band nonresonant stimulated Raman scattering (SRS) in the media H 2, D 2, CH 4, and LN 2 was used to create new families of UV lines.
Abstract: The UV excimer lasers ArF, KrCl, KrF, and XeCl were utilized to create new families of UV lines by multiple orders of broad-band nonresonant stimulated Raman scattering (SRS) in the media H 2 , D 2 , CH 4 , and LN 2 . Mixed-media and excited-state SRS were also studied.

Journal ArticleDOI
TL;DR: In this article, the advantages and limitations of combined backward wave Raman pulse compression and pulse stacking for inertial fusion applications are discussed, and a description of the major technological limitations which drive the designs of large (200 kJ) systems and some nominal systems parameters for a terawatt prototype stacker-compressor laser system are given.
Abstract: The advantages and limitations of combined backward wave Raman pulse compression and pulse stacking for inertial fusion applications are discussed. A description of the major technological limitations which drive the designs of large (200 kJ) systems and some nominal systems parameters for a terawatt prototype stacker-compressor laser system are given. It is shown that aviable short wavelength laser fusion driver employing this concept can be expected to provide an overall power multiplication of 50 with a total systems efficiency of over 3 percent.

Journal ArticleDOI
TL;DR: In this article, a simple phenomenological theory of the optogalvanic effect based on the multiplication of an electron within the plasma is presented, and the dependence of the signal on current and pressure and its temporal behavior are predicted for atoms irradiated by chopped CW lasers and pulsed lasers.
Abstract: We present a simple phenomenological theory of the optogalvanic effect based on the multiplication of an electron within the plasma. The dependence of the signal on current and pressure and its temporal behavior are predicted for atoms irradiated by chopped CW lasers and pulsed lasers. Experimental data obtained by pulsed lasers are presented and interpreted.

Journal ArticleDOI
TL;DR: In this article, a moving light scattering object was placed across the output beam of a LiNdP 4 O 12 (LNP) laser to suppress the intensity fluctuations due to external perturbations using a YIG Faraday rotation optical isolator.
Abstract: Resonance-like behaviors and spiking oscillations were observed in the LiNdP 4 O 12 (LNP) laser by placing a moving light scattering object across the output beam. Intensity fluctuations, corresponding to relaxation oscillations, were observed when the LNP laser light beam was coupled to an optical modulator as well as to an optical fiber. Classical rate equations, including a loss modulation term, were given to explain the observed phenomena. All the intensity fluctuations due to external perturbations were found to be completely suppressed by using a YIG Faraday rotation optical isolator.


Journal ArticleDOI
TL;DR: In this article, the authors have studied the properties of copper vapor lasers configured as oscillators with unstable resonator optics and as power amplifiers, and demonstrated that a 26-fold reduction in the oscillator beam divergence has been achieved over the value observed with stable optics without any power degradation.
Abstract: We have studied the properties of copper vapor lasers configured as oscillators with unstable resonator optics and as power amplifiers. With the unstable resonator, a 26-fold reduction in the oscillator beam divergence has been achieved over the value observed with stable optics without any power degradation. Time-dependent beam divergence effects in the unstable resonator have also been measured and explained. Small-signal gain, saturation fluence, and available stored energy density parameters have also been measured in oscillator amplifier experiments for both the 510.6 and 578.2 nm transitions as a function of the copper number density. These results quantify the maximum power per unit length available from these devices and furthermore, demonstrate efficient extraction of power from copper vapor lasers operated as amplifiers.

Journal ArticleDOI
H. Yonezu1, M. Ueno, T. Kamejima, I. Hayashi
TL;DR: In this article, an AlGaAs "window structure" laser with a 5 μm wide stripe was used to achieve 80 mW optical power in CW operation, which was at least one order of magnitude higher than the threshold of the catastrophic optical damage threshold in conventional structures.
Abstract: Extremely high optical power density emission was achieved with an AlGaAs "window structure" laser in CW operation as well as pulsed operation by increasing the threshold of the catastrophic optical damage (COD) on mirrors. A Zn diffused "window stripe" laser consists of the Zn diffused p-type light emitting region with low effective energy gap in the central part and the n-type window regions with high effective energy gap at both ends of the cavity. The maximum available optical power in pulsed operation was at least one order of magnitude higher than the COD threshold in conventional structures. 80 mW optical power in CW operation was achieved in the Zn diffused window stripe laser with a 5 μm wide stripe. Furthermore, gradual degradation due to the photoenhanced mirror oxidation has been reduced significantly under long term CW operation.

Journal ArticleDOI
B. Levine1, C. Shank
TL;DR: In this article, the authors proposed a new method for studying surface vibrational spectroscopy based on an extension of the picosecond stimulated Raman gain technique, which is extremely surface sensitive and can detect coverages of 1 percent of a monolayer.
Abstract: We propose a new method for studying surface vibrational spectroscopy based on an extension of the picosecond stimulated Raman gain technique. This technique is extremely surface sensitive and can detect coverages of 1 percent of a monolayer. This technique does not require ultrahigh vacuums (as do electron spectroscopies), is an extremely sensitive probe of surface local fields, has very high frequency resolution (<1 cm-1) and very short time resolution (∼ 1 ps).