Radiation back-reaction in relativistically strong and QED-strong laser fields

The emission from an electron in the field of a relativistically strong laser pulse is analyzed. At the pulse intensities of \ge 10^{22} W/cm^2 the emission from counter-propagating electrons is modified by the effects of Quantum ElectroDynamics (QED), as long as the electron energy is sufficiently high: E \ge 1 GeV. The radiation force experienced by an electron is for the first time derived from the QED principles and its applicability range is extended towards the QED-strong fields.Comment: 4 pages, 4 figure

Emission and its back-reaction accompanying electron motion in relativistically strong and QED-strong pulsed laser fields

The emission from an electron in the field of a relativistically strong laser pulse is analyzed. At pulse intensities of J > 2 10^22 W/cm2 the emission from counter-propagating electrons is modified by the effects of Quantum ElectroDynamics (QED), as long as the electron energy is sufficiently high: E > 1 GeV. The radiation force experienced by an electron is for the first time derived from the QED principles and its applicability range is extended towards the QED-strong fields.Comment: 14 pages, 5 figures. Submitted to Phys.Rev.

Ultrahigh intensity laser for laser wakefield acceleration

The next generation of high peak power CPA laser systems will be improved in compactness, simplicity, and cost. Yb:glass is a suitable choice for the amplifier medium in such a laser system necessary for an all-optical GeV accelerator. © 1997 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87564/2/68_1.pd

Relativistic attosecond physics

A study, with particle-in-cell simulations, of relativistic nonlinear optics in the regime of tight focus and ultrashort pulse duration (the λ3λ3 regime) reveals that synchronized attosecond electromagnetic pulses [N. M. Naumova, J. A. Nees, I. V. Sokolov, B. Hou, and G. A. Mourou, Phys. Rev. Lett. 92, 063902 (2004)] and attosecond electron bunches [N. Naumova, I. Sokolov, J. Nees, A. Maksimchuk, V. Yanovsky, and G. Mourou, Phys. Rev. Lett. 93, 195003 (2004)] emerge efficiently from laser interaction with overdense plasmas. The λ3λ3 concept enables a more basic understanding and a more practical implementation of these phenomena because it provides spatial and temporal isolation. The synchronous generation of strong attosecond electromagnetic pulses and dense attosecond electron bunches provides a basis for relativistic attosecond optoelectronics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87762/2/056707_1.pd

1.4 ps rise‐time high‐voltage photoconductive switching

We report on the generation of 825 V electrical pulses with 1.4 ps rise time and 4.0 ps duration using a pulse‐biased low‐temperature‐grown GaAs photoconductive switch triggered by an amplified femtosecond dye laser. Dependence of the pulse shape on both electric field and optical energy is observed and discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70925/2/APPLAB-59-12-1455-1.pd

Multi-diagnostic comparison of femtosecond and nanosecond pulsed laser plasmas

Understanding and fully characterizing highly dynamic and rapidly streaming laser ablation plasmas requires multiple techniques for monitoring effects at different stages. By combining multiple diagnostic methods, it is possible to analyze the broad time window over which these ablation plasmas develop and to learn more about the related physical processes that occur. Two laser sources, an 80 fs Ti:Sapphire laser (780 nm) and a 6 ns Nd:YAG laser (1.06 μm), are used in this work in order to compare pulse duration effects at similar wavelengths. Characteristics of the plasma produced by these two lasers are compared under conditions of comparable ablation flux. Results are presented involving correlation of time-resolved Langmuir probe data and electrostatic energy analysis for aluminum plasmas as a representative investigation for metallic systems. In addition, continuous-wave refractive index laser beam deflection is used to characterize the plasma and hot gas generated from boron nitride targets in terms of their ion and neutral atom densities. A self-similarity plasma expansion model is used to analyze the plumes under various conditions. Fundamental data obtained in this way can be relevant to laser micro-machining, laser induced breakdown spectroscopy, and pulsed laser deposition. © 2002 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70715/2/JAPIAU-92-5-2867-1.pd

A fiber‐mounted, micromachined photoconductive probe with 15 nV/Hz1/2 sensitivity

We report the performance of a micromachined, photoconductive‐sampling probe that is fabricated on low‐temperature‐grown GaAs and mounted on a single‐mode optical fiber. The epitaxial probe has a temporal resolution of 3.5 ps, a spatial resolution of 7 μm, and a sensitivity of 15 nV/(Hz)1/2 when integrated with a high impedance, junction field‐effect transistor source follower. The fiber, which couples short laser pulses to the interdigitated detector pattern on the probe, also provides flexible support and mobility. The probe’s compact cross section makes it ideal for applications as an internal‐node, picosecond‐response, photoconductive sampling probe or wave form launcher for test and characterization of integrated circuits. © 1996 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70779/2/APPLAB-69-13-1843-1.pd

A field‐sensitive photoconductive probe for sampling through passivation layers

A field‐sensitive photoconductive sampling technique has been demonstrated in measurements performed through an insulating layer without the need for conductive contact. Sampled signals are sensed by a virtual‐ground, floating‐gate amplifier without draining charge from the device under test or the photoconductive switch. The minimum detectable signal is 2.5 μV/Hz1/2 with a spatial resolution of 7 μm, while the sampling bandwidth is essentially that observed using photoconductive sampling with a conductive contact to the device under test. The photovoltaic and shot current noise are negligible in comparison with the lock‐in amplifier noise since the current flowing in this high‐impedance, floating‐gate probe is negligible. © 1996 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70307/2/APPLAB-69-15-2211-1.pd

Carrier-envelope phase stabilization of high-contrast femtosecond laser pulses with a relativistic intensity

We report on the generation of carrier-envelope phase (CEP)-stabilized pulses with a relativistic intensity and a high-contrast ratio. The CEP stabilization is achieved with a jitter of 0.95 rad0.95rad from a 0.5 kHz0.5kHz femtosecond laser pulses with a focal intensity of 2.6×1018 W/cm22.6×1018W∕cm2 and a picosecond contrast of 2.5×10−92.5×10−9. CEP noise analysis shows that the beam pointing at the pulse compressor is a dominant factor of the CEP fluctuation with our laser system.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87818/2/031113_1.pd