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- Laser wakefield acceleration (3)
- Relativistic self-focusing (3)
- Electron self-injection (2)
- Laser wakefield acceleration (numerical support of the experiment) (2)
- Laser wakefield acceleration (theory) (2)
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- PIC simulations CALDER-Circ code (2)
- stimulated Brillouin scattering (SBS) (1)
- * Ammonia; * Linestrength; Collisional broadening coefficient; Voigt; Galatry (1)
- Atomic Physics (1)
- Blowout regime (1)
- Diode (1)
- Imaging System Evaluation (1)
- Injection into expanding bubble (1)
- Laser (1)
- Laser cooling (1)
- Laser trapping (1)
- Murdock (1)
- Non-linear optics (1)
- Nonlinear plasma lens (1)
- Optical fiber (1)
- Plasma channels, laser plasma acceleration, blowout regime, electron self-injection, relativistic optical chock, PIC simulations (1)
- Poster (1)
- Pulse propagation (1)
- Q-penalty (1)
- Slow light (1)
Articles 1 - 15 of 15
Full-Text Articles in Physical Sciences and Mathematics
All-Optical Control Of Electron Trapping In Plasma Channels, Serguei Y. Kalmykov, Bradley A. Shadwick, Xavier Davoine
All-Optical Control Of Electron Trapping In Plasma Channels, Serguei Y. Kalmykov, Bradley A. Shadwick, Xavier Davoine
Serge Youri Kalmykov
The accelerating bucket of a laser-plasma accelerator (a cavity of electron density maintained by the laser pulse radiation pressure) evolves slowly, in lock-step with the optical driver, and readily traps background electrons. The trapping process can thus be controlled by purely optical means. Sharp gradients in the nonlinear refractive index produce a large frequency red-shift, localized at the leading edge of the pulse. Negative group velocity dispersion associated with the plasma response compresses the laser pulse into a relativistic optical shock (ROS), slowing the pulse (and the bucket), reducing the electron dephasing length, and limiting energy gain. Even more importantly, …
Absorption-Induced Trapping In An Anisotropic Magneto-Optical Trap, Joel A. Greenberg, M. Oria, Andrew M.C. Dawes, Daniel J. Gauthier
Absorption-Induced Trapping In An Anisotropic Magneto-Optical Trap, Joel A. Greenberg, M. Oria, Andrew M.C. Dawes, Daniel J. Gauthier
Andrew M C Dawes
We report on a simple anisotropic magneto-optical trap for neutral atoms that produces a large sample of cold atoms confined in a cylindrically-shaped volume with a high aspect ratio (100:1). Due to the large number of trapped atoms, the laser beams that propagate along the optically thick axis of the trap to cool the atoms are substantially attenuated. We demonstrate that the resulting intensity imbalance produces a net force that spatially localizes the atoms. This limits both the trap length and the total number of trapped atoms. Rotating the cooling beams by a small angle relative to the trap axis …
Distortion Management In Slow-Light Pulse Delay, Michael D. Stenner, Mark A. Neifeld, Zhaoming Zhu, Andrew M.C. Dawes, Daniel J. Gauthier
Distortion Management In Slow-Light Pulse Delay, Michael D. Stenner, Mark A. Neifeld, Zhaoming Zhu, Andrew M.C. Dawes, Daniel J. Gauthier
Andrew M C Dawes
We describe a methodology to maximize slow-light pulse delay subject to a constraint on the allowable pulse distortion. We show that optimizing over a larger number of physical variables can increase the distortion-constrained delay. We demonstrate these concepts by comparing the optimum slow-light pulse delay achievable using a single Lorentzian gain line with that achievable using a pair of closely-spaced gain lines. We predict that distortion management using a gain doublet can provide approximately a factor of 2 increase in slow-light pulse delay as compared with the optimum single-line delay. Experimental results employing Brillouin gain in optical fiber confirm our …
780 Nm Diode Lasers For Atomic Physics, Bryson Vivas, Simone Carpenter, Jenny Novak, Andrew M. C. Dawes
780 Nm Diode Lasers For Atomic Physics, Bryson Vivas, Simone Carpenter, Jenny Novak, Andrew M. C. Dawes
Andrew M C Dawes
This poster presents the results of the summer research project conducted by Bryson Vivas, Simone Carpenter, and Jenny Novak. The research was supervised by Dr. Andrew Dawes and conducted in the Photonics and Quantum Optics Lab of Pacific University.
Direct Observation Of Optical Precursors In A Region Of Anomalous Dispersion, Heejeong Jeong, Andrew M.C. Dawes, Daniel J. Gauthier
Direct Observation Of Optical Precursors In A Region Of Anomalous Dispersion, Heejeong Jeong, Andrew M.C. Dawes, Daniel J. Gauthier
Andrew M C Dawes
We create optical precursors by propagating a step-modulated optical pulse through a linear resonant dielectric absorber. The field emerging from the dielectric consists of a several-nanosecond-long spike with near 100% transmission, which decays to a constant value expected from Beer’s law. This high transmission spike might be useful for imaging applications requiring penetrating optical radiation. We compare our observations to two different theories, revealing that the spike consists of both the Sommerfeld and Brillouin precursors.
All-Optical Switching With Transverse Optical Patterns, Andrew M.C. Dawes, Lucas Illing, Joel A. Greenberg, Daniel J. Gauthier
All-Optical Switching With Transverse Optical Patterns, Andrew M.C. Dawes, Lucas Illing, Joel A. Greenberg, Daniel J. Gauthier
Andrew M C Dawes
We demonstrate an all-optical switch that operates at ultra-low-light levels and exhibits several features necessary for use in optical switching networks. An input switching beam, wavelength λ, with an energy density of 10−2 photons per optical cross section [σ=λ2 / (2π)] changes the orientation of a two-spot pattern generated via parametric instability in warm rubidium vapor. The instability is induced with less than 1 mW of total pump power and generates several μWs of output light. The switch is cascadable: the device output is capable of driving multiple inputs, and exhibits transistor-like signal-level restoration with both saturated and intermediate response …
Using Transverse Optical Patterns For Ultra-Low-Light Optical Switching, Andrew M.C. Dawes
Using Transverse Optical Patterns For Ultra-Low-Light Optical Switching, Andrew M.C. Dawes
Andrew M C Dawes
All-optical devices allow improvements in the speed of optical communication and computation systems by avoiding the conversion between the optical and electronic domains. The focus of this thesis is the experimental investigation of a new type of all-optical switch that is based on the control of optical patterns formed by nonlinear interactions between light and matter. The all-optical switch consists of a pair of light beams that counterpropagate through warm rubidium vapor. These beams induce a nonlinear optical instability that gives rise to mirrorless parametric self-oscillation and generates light in the state of polarization that is orthogonal to that of …
Broadband Sbs Slow Light In An Optical Fiber, Zhaoming Zhu, Andrew M.C. Dawes, Daniel J. Gauthier, Lin Zhang, Alan E. Willner
Broadband Sbs Slow Light In An Optical Fiber, Zhaoming Zhu, Andrew M.C. Dawes, Daniel J. Gauthier, Lin Zhang, Alan E. Willner
Andrew M C Dawes
In this paper, we investigate slow light via stimulated Brillouin scattering (SBS) in a room temperature optical fiber that is pumped by a spectrally broadened laser. Broadening the spectrum of the pump field increases the linewidth Δωp of the Stokes amplifying resonance, thereby increasing the slow-light bandwidth. One physical bandwidth limitation occurs when the linewidth becomes several times larger than the Brillouin frequency shift ΩB so that the anti-Stokes absorbing resonance substantially cancels out the Stokes amplifying resonance and, hence, the slow-light effect. We find that partial overlap of the Stokes and anti-Stokes resonances can actually lead to an enhancement …
Stable, Tunable, Quasimonoenergetic Electron Beams Produced In A Laser Wakefield Near The Threshold For Self-Injection, Sudeep Banerjee, Serguei Y. Kalmykov, Nathan D. Powers, Gregory Golovin, Vidiya Ramanathan, Nathan J. Cunningham, Kevin J. Brown, Shouyuan Chen, Isaac Ghebregziabher, Bradley A. Shadwick, Donald P. Umstadter, Benjamin A. Cowan, David L. Bruhwiler, Arnaud Beck, Erik Lefebvre
Stable, Tunable, Quasimonoenergetic Electron Beams Produced In A Laser Wakefield Near The Threshold For Self-Injection, Sudeep Banerjee, Serguei Y. Kalmykov, Nathan D. Powers, Gregory Golovin, Vidiya Ramanathan, Nathan J. Cunningham, Kevin J. Brown, Shouyuan Chen, Isaac Ghebregziabher, Bradley A. Shadwick, Donald P. Umstadter, Benjamin A. Cowan, David L. Bruhwiler, Arnaud Beck, Erik Lefebvre
Donald P. Umstadter
Stable operation of a laser-plasma accelerator near the threshold for electron self-injection in the blowout regime has been demonstrated with 25–60 TW, 30 fs laser pulses focused into a 3–4 millimeter length gas jet. Nearly Gaussian shape and high nanosecond contrast of the focused pulse appear to be critically important for controllable, tunable generation of 250–430 MeV electron bunches with a low energy spread, ~ 10 pC charge, a few-mrad divergence and pointing stability, and a vanishingly small low-energy background. The physical nature of the near-threshold behavior is examined using three-dimensional particle-in-cell simulations. Simulations indicate that properly locating the nonlinear …
Stable, Tunable, Quasimonoenergetic Electron Beams Produced In A Laser Wakefield Near The Threshold For Self-Injection, Sudeep Banerjee, Serguei Y. Kalmykov, Nathan D. Powers, Gregory Golovin, Vidiya Ramanathan, Nathan J. Cunningham, Kevin J. Brown, Shouyuan Chen, Isaac Ghebregziabher, Bradley A. Shadwick, Donald P. Umstadter, Benjamin A. Cowan, David L. Bruhwiler, Arnaud Beck, Erik Lefebvre
Stable, Tunable, Quasimonoenergetic Electron Beams Produced In A Laser Wakefield Near The Threshold For Self-Injection, Sudeep Banerjee, Serguei Y. Kalmykov, Nathan D. Powers, Gregory Golovin, Vidiya Ramanathan, Nathan J. Cunningham, Kevin J. Brown, Shouyuan Chen, Isaac Ghebregziabher, Bradley A. Shadwick, Donald P. Umstadter, Benjamin A. Cowan, David L. Bruhwiler, Arnaud Beck, Erik Lefebvre
Serge Youri Kalmykov
Stable operation of a laser-plasma accelerator near the threshold for electron self-injection in the blowout regime has been demonstrated with 25–60 TW, 30 fs laser pulses focused into a 3–4 millimeter length gas jet. Nearly Gaussian shape and high nanosecond contrast of the focused pulse appear to be critically important for controllable, tunable generation of 250–430 MeV electron bunches with a low energy spread, ~ 10 pC charge, a few-mrad divergence and pointing stability, and a vanishingly small low-energy background. The physical nature of the near-threshold behavior is examined using three-dimensional particle-in-cell simulations. Simulations indicate that properly locating the nonlinear …
Measurements Of Nh3 Linestrengths And Collisional Broadening Coefficients In N2, O2, Co2, And H2o Near 1103.46 Cm−1, Kyle Owen, Et-Touhami Es-Sebbar, Aamir Farooq
Measurements Of Nh3 Linestrengths And Collisional Broadening Coefficients In N2, O2, Co2, And H2o Near 1103.46 Cm−1, Kyle Owen, Et-Touhami Es-Sebbar, Aamir Farooq
Dr. Et-touhami Es-sebbar
Laser-based ammonia gas sensors have useful applications in many fields including combustion, atmospheric monitoring, and medical diagnostics. Calibration-free trace gas sensors require the spectroscopic parameters including linestrengths and collisional broadening coefficients to be known. Ammonia's strong ν2 vibrational band between View the MathML source has the high absorption strength needed for sensing small concentrations. Within this band, the 1103.46 cm−1 feature is one of the strongest and has minimal interference from CO2 and H2O. However, the six rotational transitions that make up this feature have not been studied previously with absorption spectroscopy due to their small line spacing ranging from …
Dark-Current-Free Laser-Plasma Acceleration In Blowout Regime Using Nonlinear Plasma Lens, Serguei Y. Kalmykov
Dark-Current-Free Laser-Plasma Acceleration In Blowout Regime Using Nonlinear Plasma Lens, Serguei Y. Kalmykov
Serge Youri Kalmykov
It is demonstrated that a thin dense plasma slab (lens), placed before a multi-centimeter-length, low-density plasma (accelerator), overfocuses an incident petawatt laser pulse at a controlled location inside the accelerator, creating an expanding electron density bubble that traps plasma electrons over a brief time interval. As soon as the pulse stabilizes and self-guiding begins, the bubble stabilizes and transforms into the first (non-broken) bucket of a conventional three-dimensional nonlinear plasma wave, eliminating any chance for further injection. A well collimated, quasi-monoenergetic electron bunch with a zero low-energy background further accelerates to a multi-GeV energy.
Effects Of N2o And O2 Addition To Nitrogen Townsend Dielectric Barrier Discharges At Atmospheric Pressure On The Absolute Ground-State Atomic Nitrogen Density, Et. Es-Sebbar, N. Gherardi, F. Massines
Effects Of N2o And O2 Addition To Nitrogen Townsend Dielectric Barrier Discharges At Atmospheric Pressure On The Absolute Ground-State Atomic Nitrogen Density, Et. Es-Sebbar, N. Gherardi, F. Massines
Dr. Et-touhami Es-sebbar
Absolute ground-state density of nitrogen atoms N (2p3 4S3/2) in non-equilibrium Townsend dielectric barrier discharges (TDBDs) at atmospheric pressure sustained in N2/N2O and N2/O2 gas mixtures has been measured using Two-photon absorption laser-induced fluorescence (TALIF) spectroscopy. The quantitative measurements have been obtained by TALIF calibration using krypton as a reference gas. We previously reported that the maximum of N (2p3 4S3/2) atom density is around 3 × 1014 cm−3 in pure nitrogen TDBD, and that this maximum depends strongly on the mean energy dissipated in the gas. In the two gas mixtures studied here, results show that the absolute N …
Evaluation Of The In Situ Ichthyoplankton Imaging System (Isiis): Comparison With The Traditional (Bongo Net) Sampler, Robert K. Cowen, Adam T. Greer, Cedric M. Guigand, Jonathan A. Hare, David E. Richardson, Harvey J. Walsh
Evaluation Of The In Situ Ichthyoplankton Imaging System (Isiis): Comparison With The Traditional (Bongo Net) Sampler, Robert K. Cowen, Adam T. Greer, Cedric M. Guigand, Jonathan A. Hare, David E. Richardson, Harvey J. Walsh
Adam T. Greer
Plankton and larval fish sampling programs often are limited by a balance between sampling frequency (for precision) and costs. Advancements in sampling techniques hold the potential to add considerable efficiency and, therefore, add sampling frequency to improve precision. We compare a newly developed plankton imaging system, In Situ Ichthyoplankton Imaging System (ISIIS), with a bongo sampler, which is a traditional plankton sampling gear developed in the 1960s. Comparative sampling was conducted along 2 transects ~30–40 km long. Over 2 days, we completed 36 ISIIS tow-yo undulations and 11 bongo oblique tows, each from the surface to within 10 m of …
Temperature-Dependent Absorption Cross-Section Measurements Of 1-Butene (1-C4h8) In Vuv And Ir, Et-Touhami Es-Sebbar, Yves Benilan, Aamir Farooq
Temperature-Dependent Absorption Cross-Section Measurements Of 1-Butene (1-C4h8) In Vuv And Ir, Et-Touhami Es-Sebbar, Yves Benilan, Aamir Farooq
Dr. Et-touhami Es-sebbar
Vacuum ultraviolet (VUV) and infrared (IR) absorption cross-section measurements of 1-butene (1-C4H8; CH2=CHCH2CH3; Butylene) are reported over the temperature range of 296–529 K. The VUV measurements are performed between 115 and 205 nm using synchrotron radiation as a tunable VUV light source. Fourier Transform Infrared (FTIR) spectroscopy is employed to measure absorption cross-section and band strengths in the IR region between 1.54 and 25 μm (∼6500–400 cm−1). The measured room-temperature VUV and IR absorption cross-sections are compared with available literature data and are found to be in good agreement. The oscillator strength for the electronic transition (A1A′→X1A′) around 150–205 nm …