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Michael Raymer

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Oleg Yu Vorobyev

Siberian Federal University

Katherine Butler Schofield

King's College London

Alejandra B Osorio

Wellesley College

Norwegian University of Science and Technology

University of Florida

The University of Texas at Austin

Shabib H . Syed

University of the Punjab, Lahore, Pakistan

Javier Marín-López

Universidad de Jaén

Homi Bhabha National Institute (HBNI, BARC, MUMBAI)

ELCHİN SULEYMANOV

Azerbaijan National Academy of Sciences

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Papers by Michael Raymer

Near quantum-limited phase memory in an optical amplifier

Optical Society of America Annual Meeting

Probing the quantum noise level with respect to a coherent input has recently received much atten... more Probing the quantum noise level with respect to a coherent input has recently received much attention. Several researchers have probed this question by examining the level of external optical input needed to influence the output field of a quantum noise amplifier. For example, it has been found that it takes, on average, about one photon per (temporal) mode to control the phase of the output field of a Raman amplifier.1 A similar result has been seen in optical parametric amplification.2 In contrast to using light to seed the amplification, we have investigated the level of initial molecular coherence needed to control the phase of the output field of a Raman amplifier. Two laser pulses, separated in time, were used to pump a common set of hydrogen molecules producing two Stokes pulses via stimulated Raman scattering. The relative phase of the two Stokes pulses was measured interferometrically. The variance of this relative phase is a direct measure of the memory of the molecular co...

Coherent propagation of Stokes light in a collisionally broadened three-level amplifier

Physical Review A, 1989

We undertake a theoretical investigation of the coherent optical propagation of Stokes light in a... more We undertake a theoretical investigation of the coherent optical propagation of Stokes light in a collisionally broadened three-level Raman amplifier. The Stokes light consists of two distinct spec- tral components: off-resonance stimulated Raman scattering and on-resonance stimulated fluores- cence, induced by collisional transfer of population to a near-resonant intermediate state of the atomic system. Our model is based on the semiclassical Maxwell-Bloch formalism where the sepa- ration of the Stokes light into two components results in an expansion from the usual 9 to 13 atomic variables. We investigate the model both analytically and numerically. We point out the physical contributions to the simultaneous evolution of pump, fluorescence, and Raman light. We discuss the development during propagation of these separate pulses, emphasizing the nonlinear effects that lead to saturation.

Delay-time statistics of cooperative emission in the presence of homogeneous line broadening

Physical Review A, 1989

We have developed a theoretical model that allows us to study the delay-time statistics of superf... more We have developed a theoretical model that allows us to study the delay-time statistics of superfluorescent pulses for the case of collisional broadening with a Lorentzian line shape. Our mode1 is based upon a more robust definition of delay time, based upon an energy rather than an in- tensity reference. We calculate the probability distribution of delay times in the initiation regime of superfluorescence, where the inversion is essentially constant. We find that, as the collisional de- phasing rate is increased, the mean delay time increases and the distribution broadens. We compare our results with those for the case of inhomogeneous broadening with a Lorentzian line shape and find the unexpected result that the statistical behavior is identical.

Theory of time-dependent intense-field collisional resonance fluorescence

Physical Review A, 1983

The time-dependent theory of Courtens and SzBce is generalized using the approach of Burnett et a... more The time-dependent theory of Courtens and SzBce is generalized using the approach of Burnett et al. to derive time-dependent spectral intensities of resonance fluorescence from atoms driven by a pulsed laser in the presence of collisions. These results are valid both for laser detunings inside and outside the usual impact region of the spectrum, including Zee- man degeneracy effects. We apply this theory to a simple but important example (J=0 to J=1) to obtain quantitative predictions for the observable scattered-light spectrum which can be directly compared with recent experiments.

Measuring the Quantum Polarization State of Light

Quantum Communication, Computing, and Measurement 2

Quantum-state tomography is proposed as a means to achieve a complete measurement of the quantum ... more Quantum-state tomography is proposed as a means to achieve a complete measurement of the quantum polarization state of a light wave. A set of measurements using dual-polarization balanced homodyne detection is shown to be tomographi-cally complete with respect to the statistics of the SU(2) Stokes operators on the Poincaré sphere. Complete reconstruction of the polarization sector of the density matrix

High-Efficiency, Ultrafast Photon-Number Statistics from Phase-Averaged Homodyne Detection

Coherence and Quantum Optics VII, 1996

The measurement of photon-number statistics is an essential element of quantum optics. Neverthele... more The measurement of photon-number statistics is an essential element of quantum optics. Nevertheless, conventional techniques are limited in their ability to measure the photon-count distribution p(n) with high quantum efficiency (QE), high number resolution, and high spatial-temporal resolution. The present work reviews a recently developed technique --phase-averaged homodyne detection -- which can provide a nearly ideal method for measuring photon statistics.[1] Its QE can approach 100%, while maintaining high number resolution (can distinguish between p(n) and p(n +1)), as well as sub-picosecond temporal resolution and single-mode spatial discrimination. In addition, it provides simultaneous temporal and spectral resolution. [2]

Simultaneous Observations of Stimulated Raman Scattering and Stimulated Collision-Induced Fluorescence

Physical Review Letters, 1977

We have observed collisional redistribution of laser light scattered by a three-level atom, thall... more We have observed collisional redistribution of laser light scattered by a three-level atom, thallium, in the presence of argon. The two observed spectral components correspond to Raman scattering and collision-induced fluorescence. We have seen the growth of both components from spontaneous to stimulated scattering as the laser intensity is increased. While the gain for the Raman component agrees with theory, the observed gain of the collision-induced fluorescence is over an order of magnitude lower than predicted.

Observation of Moving Wave Packets Reveals Their Quantum State

Physical Review Letters, 1996

We show how to infer the quantum state of a wave packet from position probability distributions m... more We show how to infer the quantum state of a wave packet from position probability distributions measured during the packet's motion in an arbitrary potential. We assume a nonrelativistic onedimensional or radial wave packet. Temporal Fourier transformation and spatial sampling with respect to a newly found set of functions project the density-matrix elements out of the probability distributions. The sampling functions are derivatives of products of regular and irregular wave functions. We note that the ability to infer quantum states in this way depends on the structure of the Schrödinger equation.

Separability criterion for separate quantum systems

Physical Review A, 2003

Two-photon wave mechanics

Physical Review A, 2006

The position-representation wave function for multi-photon states and its equation of motion are ... more The position-representation wave function for multi-photon states and its equation of motion are introduced. A major strength of the theory is that it describes the complete evolution (including polarization and entanglement) of multi-photon states propagating through inhomogeneous media. As a demonstration of the two-photon wave function's use, we show how two photons in an orbitalangular-momentum entangled state decohere upon propagation through a turbulent atmosphere.

Complete experimental characterization of the quantum state of a light mode via the Wigner function and the density matrix: application to quantum phase distributions of vacuum and squeezed-vacuum states

Physica Scripta, 1993

We have used the recently demonstrated method of optical homodyne tomography (OHT) to measure the... more We have used the recently demonstrated method of optical homodyne tomography (OHT) to measure the Wigner quasiprobability distribution (Wigner function) and the density matrix for both a squeezed-vacuum and a vacuum state of a single spatial-temporal mode of the electromagnetic field. This method consists of measuring a set of probability distributions for many different Hilbert-space representations of the field-quadrature amplitude,

Turn-on transient statistics and dynamics in a multimode, short-cavity laser

Optics Letters, 1992

The statistics of turn-on delay times for a longitudinal mode and the total intensity from a mult... more The statistics of turn-on delay times for a longitudinal mode and the total intensity from a multimode, standingwave, short-cavity dye laser are measured and compared with numerical simulations of a multimode theory of laser dynamics. Differences between the measurements and the theory for the average and standard deviation of the turn-on time are due to transitory modes that decay as a result of frequency-dependent losses and gains. Associated with this phenomenon is a kink in the time evolution of the mode intensity that represents a transition in the dynamics from domination by independent growth of all modes to domination by competition between modes with differing net gains. This unequal competition increases the average and standard deviation of the mode turn-on time. Valuable discussions with M. Belsley, H. J.

Quantum state entanglement and readout of collective atomic-ensemble modes and optical wave packets by stimulated Raman scattering

Journal of Modern Optics, 2004

A proposal is made for the creation of macroscopic quantum states of collective atomic-ensemble v... more A proposal is made for the creation of macroscopic quantum states of collective atomic-ensemble variables by the use of stimulated Raman scattering (SRS), followed by conditional optical measurement. After the completion of the SRS process, one is able to reverse the process and to return all the atoms to their ground states in such a way that reads out an arbitrary quantum state of the collective atomic field and writes this state onto the outgoing optical field. This scheme can be used for the creation of entanglement between two distant atomic ensembles. The quantum analysis of the SRS process treats one-dimensional spatial-temporal propagation accurately. Remarkably, it is found that this multimode problem can be simplified to a twomode problem involving spatial-temporal wave-packet modes of the optical and atomic collective fields. This improves the understanding of the entanglement created in this system.

Linear optical sampling

IEEE Photonics Technology Letters, 2003

Observation of Kastler ring emission from a short-cavity laser

Applied Optics, 1993

Conical ring emission from a short-cavity dye laser has been observed and modeled as Kastler ring... more Conical ring emission from a short-cavity dye laser has been observed and modeled as Kastler rings, that is, the high-angle emission modes of a plano-plano (Fabry-Perot) laser cavity in agreement with the predictions made 31 years ago by Kastler [Appl. Opt. 1, 17 (1962)]. The excitation of the discrete rings is due to a transfer of energy from the axial modes rather than to spontaneous emission. The mechanism for energy transfer is argued to be scattering of light from imperfections on the mirror surfaces.

Pairwise entanglement and readout of atomic-ensemble and optical wave-packet modes in traveling-wave Raman interactions

Physical Review A, 2006

Experimental quantum key distribution using macroscopic non-classical optical pulses

Conference on Lasers and Electro-Optics/International Quantum Electronics Conference and Photonic Applications Systems Technologies, 2004

We present experimental results for a proof-of-principle demonstration of a quantum key-distribut... more

Twin photon beams resulting from the interference of independent broadband squeezed vacua

Physical Review A, 1992

ABSTRACT We show theoretically that by interfering two independent, equally squeezed vacuum field... more ABSTRACT We show theoretically that by interfering two independent, equally squeezed vacuum fields on a simple 50-50 beam splitter one can produce twin beams with perfect intensity correlation. Using a broadband theory of traveling-wave, parametric down-conversion, we calculate the noise statistics of the difference intensity of the two fields leaving the beam splitter as a function of the relative phase between the two independent squeezed fields. The noise statistics are found to vary from twin photon beams to superthermal fluctuations for a broad range of electronic detection frequencies near zero frequency (dc). In the case of ideal detectors, essentially perfect noise cancellation is predicted for arbitrary degrees of squeezing when the two beams are mixed with the proper phase. The results are fairly robust with respect to the effects of imperfect detection efficiency and unequal squeezing strengths in the two fields.

Theory of stimulated Raman scattering with broad-band lasers

Physical Review A, 1979

I'll V SI (A I 111 > II » \ VOM Ml. I i), MM Uli; (. 00 o iH iH 9 Cu Theory of .'.timuLttod Maman... more I'll V SI (A I 111 > II » \ VOM Ml. I i), MM Uli; (. 00 o iH iH 9 Cu Theory of .'.timuLttod Maman «•litlerinR with broad-band l:v.cn> M. (j. K:i\imT,* J. Moslinv.ki.' and J U ( . { "'< , 'w ! Joint ttniiiuk' l»r (^bttrawfk' Aitrofltyitt'K tV.ii.'iwH' of CO/IIFU.«'-' ami Xuthmal tturniu vf SU'nijrUt, PmiUer. Calutado 80i09 (Kc>nn-.l It. IV..ciul.i-r i<*1ft The auihon h.wc c^irnJeil the tlunrv of Mmuilirc^ Iv.^man Kcatfrfmt: to include the cfT(vt\ of laser bdtitjuijlhv in IH«II t!;r transient arul sl.v.I».state fr^nrcs. 1 he t;:sc of two ii'liTacting laser beams, a ptnip laser KIKI a proln-(M^kcs) laser, is tre.ittil. t'sing ,he piiasr-UitTusum niiKtcl k>i laser haiiJ»Klth, tliu autlmrs demonstrate that in the absence of dupmrnn, the foruaul Katiian gain is essentially mdcjH-iulcut of the laser banduidths in the hit'hY.ain limit, v.title in the low pain limit the .gain locMiiinit is mvcisely pro|HYtiunal to the sum of the batuUtilths. It is förther sliown that nhen the pump-laser bandwidth is murh larger than the linewidth *»f the Raman medium, tlie stu.ralatcd Stnl.es ftitpnl assumes the janie »iscttrum as llie pump User in (he high-gam limit. A po.sible jrHerffc-ation of Ihe5c results is discussed assuming a "p!ia'.e Kickinf" of the Stokes phase to the fluu-aiions in [he pump-laser phase, due to the nonlinea. interaction of the two beams throu(h the Raman medium. I. INTRODUCTtON The eftecls of finite laser bandwidth are being recognized as important in Ihe study u( nunlincar optical processes. Resonance fluorescence,'*' two-photon absorption,''" recond harmonic tcneralion,* mulliplioton ionization, , °'" and Ktimulatcd Raman ucattcrlng are all areas in which key elemenla of uiulcrstanding Ueiiend on the aliilily to model the laser, not as a monochromatic wave of definite phrtse and amplitude, hut as a mulltmode broad-band wave wMi fluctuating phase and amplitude. The problem c' stimulated Raman scattering (SRS) is (specially timely In liRht of ongoing efforts to use it as method (or developing new coherent light sources 14 as well ai compressing high-energy laser pulses to achieve higher peak powers for use in laser fusion." In applications of these types a detailed understanding of all the factors influencing the efficiencies of the processes is obviously desirable. However, one Important (actor, laser bandwidth, has not yet been fully explored. Recently, two groups"'" have observed a Urge (orward-buckwArd asymmetry of the Raman gain, which they attribute to the broad-band nature o( the pump laser used These were in the absence of other effects, such aö Holf-fucusing or extraneous feedback, which iai) known to produce anomalous gains." These aEjüiinelries arc consistent with several llieorcttcal '-ediclions 14 " that in the backward direction (uoiintcrpropagating pump and Stokes wave:) the gain ewlftcienl is proportional to (r ♦ r^r'i where T and l L are the spectral widths of Ihe Hainan mc-dmm and lite pump laser, respectively; while, in tliv forward direction, in the absence of disporsiun o( the Stokes wave relative to the pump wave, the gain cocHicient is 19 proportional to T' 1 alone. Carman el at." refer to this as "the rather startling conclusion.., that the Stokes gain is independent of the (requency spectrum of tl«? (pump) laser... even if this spectrum is much broader than r," Thus when r 1 is much larger than r the forward gain is much larger than the backward gain. These results go against intuition based on the idea that gain should depend on the number of photons per unit frequency in the pump beam. Apparently, the concept of photons as independent incoherent bundles is inadequate to describe the subtleties in the SRS problem. The purpose of this paper is to further develop the theory of SRS, including the effects of finite laser bandwidths, in a way that allows explicit calculation of thv gain and spectrum of the Stokes wave. We consider, as in Fig, , a medium of three-level atoms interacting with two classical FIQ. 1, Tliivc-linel atom Interacting with a pump laser with (niiuemty uj, and a pro*«! (Stolxs) later with tioquoncy w ( . T'liu eumnhttivc detimin^.s are A L and A 4 .. mi

Beam-pointing fluctuations in gain-guided amplifiers

Physical Review Letters, 1991

We report a measurement of the quantum-mechanical beam-pointing fluctuations in the output of a g... more We report a measurement of the quantum-mechanical beam-pointing fluctuations in the output of a gain-guided, single-pass amplifier using stimulated Raman scattering. The experimental result is in reasonable agreement with a theoretical model that incorporates the effects of excess spontaneous noise associated with the transverse modes of a gain-guided amplifier

Near quantum-limited phase memory in an optical amplifier

Optical Society of America Annual Meeting

Probing the quantum noise level with respect to a coherent input has recently received much atten... more Probing the quantum noise level with respect to a coherent input has recently received much attention. Several researchers have probed this question by examining the level of external optical input needed to influence the output field of a quantum noise amplifier. For example, it has been found that it takes, on average, about one photon per (temporal) mode to control the phase of the output field of a Raman amplifier.1 A similar result has been seen in optical parametric amplification.2 In contrast to using light to seed the amplification, we have investigated the level of initial molecular coherence needed to control the phase of the output field of a Raman amplifier. Two laser pulses, separated in time, were used to pump a common set of hydrogen molecules producing two Stokes pulses via stimulated Raman scattering. The relative phase of the two Stokes pulses was measured interferometrically. The variance of this relative phase is a direct measure of the memory of the molecular co...

Coherent propagation of Stokes light in a collisionally broadened three-level amplifier

Physical Review A, 1989

We undertake a theoretical investigation of the coherent optical propagation of Stokes light in a... more We undertake a theoretical investigation of the coherent optical propagation of Stokes light in a collisionally broadened three-level Raman amplifier. The Stokes light consists of two distinct spec- tral components: off-resonance stimulated Raman scattering and on-resonance stimulated fluores- cence, induced by collisional transfer of population to a near-resonant intermediate state of the atomic system. Our model is based on the semiclassical Maxwell-Bloch formalism where the sepa- ration of the Stokes light into two components results in an expansion from the usual 9 to 13 atomic variables. We investigate the model both analytically and numerically. We point out the physical contributions to the simultaneous evolution of pump, fluorescence, and Raman light. We discuss the development during propagation of these separate pulses, emphasizing the nonlinear effects that lead to saturation.

Delay-time statistics of cooperative emission in the presence of homogeneous line broadening

Physical Review A, 1989

We have developed a theoretical model that allows us to study the delay-time statistics of superf... more We have developed a theoretical model that allows us to study the delay-time statistics of superfluorescent pulses for the case of collisional broadening with a Lorentzian line shape. Our mode1 is based upon a more robust definition of delay time, based upon an energy rather than an in- tensity reference. We calculate the probability distribution of delay times in the initiation regime of superfluorescence, where the inversion is essentially constant. We find that, as the collisional de- phasing rate is increased, the mean delay time increases and the distribution broadens. We compare our results with those for the case of inhomogeneous broadening with a Lorentzian line shape and find the unexpected result that the statistical behavior is identical.

Theory of time-dependent intense-field collisional resonance fluorescence

Physical Review A, 1983

The time-dependent theory of Courtens and SzBce is generalized using the approach of Burnett et a... more The time-dependent theory of Courtens and SzBce is generalized using the approach of Burnett et al. to derive time-dependent spectral intensities of resonance fluorescence from atoms driven by a pulsed laser in the presence of collisions. These results are valid both for laser detunings inside and outside the usual impact region of the spectrum, including Zee- man degeneracy effects. We apply this theory to a simple but important example (J=0 to J=1) to obtain quantitative predictions for the observable scattered-light spectrum which can be directly compared with recent experiments.

Measuring the Quantum Polarization State of Light

Quantum Communication, Computing, and Measurement 2

Quantum-state tomography is proposed as a means to achieve a complete measurement of the quantum ... more Quantum-state tomography is proposed as a means to achieve a complete measurement of the quantum polarization state of a light wave. A set of measurements using dual-polarization balanced homodyne detection is shown to be tomographi-cally complete with respect to the statistics of the SU(2) Stokes operators on the Poincaré sphere. Complete reconstruction of the polarization sector of the density matrix

High-Efficiency, Ultrafast Photon-Number Statistics from Phase-Averaged Homodyne Detection

Coherence and Quantum Optics VII, 1996

The measurement of photon-number statistics is an essential element of quantum optics. Neverthele... more The measurement of photon-number statistics is an essential element of quantum optics. Nevertheless, conventional techniques are limited in their ability to measure the photon-count distribution p(n) with high quantum efficiency (QE), high number resolution, and high spatial-temporal resolution. The present work reviews a recently developed technique --phase-averaged homodyne detection -- which can provide a nearly ideal method for measuring photon statistics.[1] Its QE can approach 100%, while maintaining high number resolution (can distinguish between p(n) and p(n +1)), as well as sub-picosecond temporal resolution and single-mode spatial discrimination. In addition, it provides simultaneous temporal and spectral resolution. [2]

Simultaneous Observations of Stimulated Raman Scattering and Stimulated Collision-Induced Fluorescence

Physical Review Letters, 1977

We have observed collisional redistribution of laser light scattered by a three-level atom, thall... more We have observed collisional redistribution of laser light scattered by a three-level atom, thallium, in the presence of argon. The two observed spectral components correspond to Raman scattering and collision-induced fluorescence. We have seen the growth of both components from spontaneous to stimulated scattering as the laser intensity is increased. While the gain for the Raman component agrees with theory, the observed gain of the collision-induced fluorescence is over an order of magnitude lower than predicted.

Observation of Moving Wave Packets Reveals Their Quantum State

Physical Review Letters, 1996

We show how to infer the quantum state of a wave packet from position probability distributions m... more We show how to infer the quantum state of a wave packet from position probability distributions measured during the packet's motion in an arbitrary potential. We assume a nonrelativistic onedimensional or radial wave packet. Temporal Fourier transformation and spatial sampling with respect to a newly found set of functions project the density-matrix elements out of the probability distributions. The sampling functions are derivatives of products of regular and irregular wave functions. We note that the ability to infer quantum states in this way depends on the structure of the Schrödinger equation.

Separability criterion for separate quantum systems

Physical Review A, 2003

Two-photon wave mechanics

Physical Review A, 2006

The position-representation wave function for multi-photon states and its equation of motion are ... more The position-representation wave function for multi-photon states and its equation of motion are introduced. A major strength of the theory is that it describes the complete evolution (including polarization and entanglement) of multi-photon states propagating through inhomogeneous media. As a demonstration of the two-photon wave function's use, we show how two photons in an orbitalangular-momentum entangled state decohere upon propagation through a turbulent atmosphere.

Complete experimental characterization of the quantum state of a light mode via the Wigner function and the density matrix: application to quantum phase distributions of vacuum and squeezed-vacuum states

Physica Scripta, 1993

We have used the recently demonstrated method of optical homodyne tomography (OHT) to measure the... more We have used the recently demonstrated method of optical homodyne tomography (OHT) to measure the Wigner quasiprobability distribution (Wigner function) and the density matrix for both a squeezed-vacuum and a vacuum state of a single spatial-temporal mode of the electromagnetic field. This method consists of measuring a set of probability distributions for many different Hilbert-space representations of the field-quadrature amplitude,

Turn-on transient statistics and dynamics in a multimode, short-cavity laser

Optics Letters, 1992

The statistics of turn-on delay times for a longitudinal mode and the total intensity from a mult... more The statistics of turn-on delay times for a longitudinal mode and the total intensity from a multimode, standingwave, short-cavity dye laser are measured and compared with numerical simulations of a multimode theory of laser dynamics. Differences between the measurements and the theory for the average and standard deviation of the turn-on time are due to transitory modes that decay as a result of frequency-dependent losses and gains. Associated with this phenomenon is a kink in the time evolution of the mode intensity that represents a transition in the dynamics from domination by independent growth of all modes to domination by competition between modes with differing net gains. This unequal competition increases the average and standard deviation of the mode turn-on time. Valuable discussions with M. Belsley, H. J.

Quantum state entanglement and readout of collective atomic-ensemble modes and optical wave packets by stimulated Raman scattering

Journal of Modern Optics, 2004

A proposal is made for the creation of macroscopic quantum states of collective atomic-ensemble v... more A proposal is made for the creation of macroscopic quantum states of collective atomic-ensemble variables by the use of stimulated Raman scattering (SRS), followed by conditional optical measurement. After the completion of the SRS process, one is able to reverse the process and to return all the atoms to their ground states in such a way that reads out an arbitrary quantum state of the collective atomic field and writes this state onto the outgoing optical field. This scheme can be used for the creation of entanglement between two distant atomic ensembles. The quantum analysis of the SRS process treats one-dimensional spatial-temporal propagation accurately. Remarkably, it is found that this multimode problem can be simplified to a twomode problem involving spatial-temporal wave-packet modes of the optical and atomic collective fields. This improves the understanding of the entanglement created in this system.

Linear optical sampling

IEEE Photonics Technology Letters, 2003

Observation of Kastler ring emission from a short-cavity laser

Applied Optics, 1993

Conical ring emission from a short-cavity dye laser has been observed and modeled as Kastler ring... more Conical ring emission from a short-cavity dye laser has been observed and modeled as Kastler rings, that is, the high-angle emission modes of a plano-plano (Fabry-Perot) laser cavity in agreement with the predictions made 31 years ago by Kastler [Appl. Opt. 1, 17 (1962)]. The excitation of the discrete rings is due to a transfer of energy from the axial modes rather than to spontaneous emission. The mechanism for energy transfer is argued to be scattering of light from imperfections on the mirror surfaces.

Pairwise entanglement and readout of atomic-ensemble and optical wave-packet modes in traveling-wave Raman interactions

Physical Review A, 2006

Experimental quantum key distribution using macroscopic non-classical optical pulses

Conference on Lasers and Electro-Optics/International Quantum Electronics Conference and Photonic Applications Systems Technologies, 2004

We present experimental results for a proof-of-principle demonstration of a quantum key-distribut... more

Twin photon beams resulting from the interference of independent broadband squeezed vacua

Physical Review A, 1992

ABSTRACT We show theoretically that by interfering two independent, equally squeezed vacuum field... more ABSTRACT We show theoretically that by interfering two independent, equally squeezed vacuum fields on a simple 50-50 beam splitter one can produce twin beams with perfect intensity correlation. Using a broadband theory of traveling-wave, parametric down-conversion, we calculate the noise statistics of the difference intensity of the two fields leaving the beam splitter as a function of the relative phase between the two independent squeezed fields. The noise statistics are found to vary from twin photon beams to superthermal fluctuations for a broad range of electronic detection frequencies near zero frequency (dc). In the case of ideal detectors, essentially perfect noise cancellation is predicted for arbitrary degrees of squeezing when the two beams are mixed with the proper phase. The results are fairly robust with respect to the effects of imperfect detection efficiency and unequal squeezing strengths in the two fields.

Theory of stimulated Raman scattering with broad-band lasers

Physical Review A, 1979

I'll V SI (A I 111 > II » \ VOM Ml. I i), MM Uli; (. 00 o iH iH 9 Cu Theory of .'.timuLttod Maman... more I'll V SI (A I 111 > II » \ VOM Ml. I i), MM Uli; (. 00 o iH iH 9 Cu Theory of .'.timuLttod Maman «•litlerinR with broad-band l:v.cn> M. (j. K:i\imT,* J. Moslinv.ki.' and J U ( . { "'< , 'w ! Joint ttniiiuk' l»r (^bttrawfk' Aitrofltyitt'K tV.ii.'iwH' of CO/IIFU.«'-' ami Xuthmal tturniu vf SU'nijrUt, PmiUer. Calutado 80i09 (Kc>nn-.l It. IV..ciul.i-r i<*1ft The auihon h.wc c^irnJeil the tlunrv of Mmuilirc^ Iv.^man Kcatfrfmt: to include the cfT(vt\ of laser bdtitjuijlhv in IH«II t!;r transient arul sl.v.I».state fr^nrcs. 1 he t;:sc of two ii'liTacting laser beams, a ptnip laser KIKI a proln-(M^kcs) laser, is tre.ittil. t'sing ,he piiasr-UitTusum niiKtcl k>i laser haiiJ»Klth, tliu autlmrs demonstrate that in the absence of dupmrnn, the foruaul Katiian gain is essentially mdcjH-iulcut of the laser banduidths in the hit'hY.ain limit, v.title in the low pain limit the .gain locMiiinit is mvcisely pro|HYtiunal to the sum of the batuUtilths. It is förther sliown that nhen the pump-laser bandwidth is murh larger than the linewidth *»f the Raman medium, tlie stu.ralatcd Stnl.es ftitpnl assumes the janie »iscttrum as llie pump User in (he high-gam limit. A po.sible jrHerffc-ation of Ihe5c results is discussed assuming a "p!ia'.e Kickinf" of the Stokes phase to the fluu-aiions in [he pump-laser phase, due to the nonlinea. interaction of the two beams throu(h the Raman medium. I. INTRODUCTtON The eftecls of finite laser bandwidth are being recognized as important in Ihe study u( nunlincar optical processes. Resonance fluorescence,'*' two-photon absorption,''" recond harmonic tcneralion,* mulliplioton ionization, , °'" and Ktimulatcd Raman ucattcrlng are all areas in which key elemenla of uiulcrstanding Ueiiend on the aliilily to model the laser, not as a monochromatic wave of definite phrtse and amplitude, hut as a mulltmode broad-band wave wMi fluctuating phase and amplitude. The problem c' stimulated Raman scattering (SRS) is (specially timely In liRht of ongoing efforts to use it as method (or developing new coherent light sources 14 as well ai compressing high-energy laser pulses to achieve higher peak powers for use in laser fusion." In applications of these types a detailed understanding of all the factors influencing the efficiencies of the processes is obviously desirable. However, one Important (actor, laser bandwidth, has not yet been fully explored. Recently, two groups"'" have observed a Urge (orward-buckwArd asymmetry of the Raman gain, which they attribute to the broad-band nature o( the pump laser used These were in the absence of other effects, such aö Holf-fucusing or extraneous feedback, which iai) known to produce anomalous gains." These aEjüiinelries arc consistent with several llieorcttcal '-ediclions 14 " that in the backward direction (uoiintcrpropagating pump and Stokes wave:) the gain ewlftcienl is proportional to (r ♦ r^r'i where T and l L are the spectral widths of Ihe Hainan mc-dmm and lite pump laser, respectively; while, in tliv forward direction, in the absence of disporsiun o( the Stokes wave relative to the pump wave, the gain cocHicient is 19 proportional to T' 1 alone. Carman el at." refer to this as "the rather startling conclusion.., that the Stokes gain is independent of the (requency spectrum of tl«? (pump) laser... even if this spectrum is much broader than r," Thus when r 1 is much larger than r the forward gain is much larger than the backward gain. These results go against intuition based on the idea that gain should depend on the number of photons per unit frequency in the pump beam. Apparently, the concept of photons as independent incoherent bundles is inadequate to describe the subtleties in the SRS problem. The purpose of this paper is to further develop the theory of SRS, including the effects of finite laser bandwidths, in a way that allows explicit calculation of thv gain and spectrum of the Stokes wave. We consider, as in Fig, , a medium of three-level atoms interacting with two classical FIQ. 1, Tliivc-linel atom Interacting with a pump laser with (niiuemty uj, and a pro*«! (Stolxs) later with tioquoncy w ( . T'liu eumnhttivc detimin^.s are A L and A 4 .. mi

Beam-pointing fluctuations in gain-guided amplifiers

Physical Review Letters, 1991

We report a measurement of the quantum-mechanical beam-pointing fluctuations in the output of a g... more We report a measurement of the quantum-mechanical beam-pointing fluctuations in the output of a gain-guided, single-pass amplifier using stimulated Raman scattering. The experimental result is in reasonable agreement with a theoretical model that incorporates the effects of excess spontaneous noise associated with the transverse modes of a gain-guided amplifier