scholarly journals Temporal contrast in Ti:sapphire lasers, characterization and control

1998 ◽  
Vol 4 (2) ◽  
pp. 449-458 ◽  
Author(s):  
M. Nantel ◽  
J. Itatani ◽  
An-Chun Tien ◽  
J. Faure ◽  
D. Kaplan ◽  
...  
Keyword(s):  
Temporal Contrast ◽  
Ti:Sapphire Lasers ◽  
And Control

Degradation of picosecond temporal contrast of Ti:sapphire lasers with coherent pedestals

2016 ◽  
Vol 41 (19) ◽  
pp. 4441 ◽  
Author(s):  
Nikita Khodakovskiy ◽  
Mikhail Kalashnikov ◽  
Emilien Gontier ◽  
Franck Falcoz ◽  
Pierre-Mary Paul
Keyword(s):  
Temporal Contrast ◽  
Ti:Sapphire Lasers

scholarly journals High-power Ti:Sapphire lasers: Temporal contrast and spectral narrowing

2007 ◽  
Vol 25 (2) ◽  
pp. 219-223 ◽  
Author(s):  
M Kalashnikov ◽  
K Osvay ◽  
W Sandner
Keyword(s):  
Power Level ◽  
Spectral Bandwidth ◽  
Temporal Contrast ◽  
Chirped Pulse ◽  
Pulse Amplification ◽  
Ti:Sapphire Lasers ◽  
Spectral Narrowing ◽  
Chirped Pulses ◽  
Chirped Pulse Amplification ◽  
Gain Narrowing

New extensions of the chirped pulse amplification (CPA) scheme designed specially for petawatt Ti:Sapphire lasers are considered. The two new schemes support a spectral bandwidth sufficient for 20 fs pulses and a temporal contrast of 1012. The Double CPA scheme consists of two CPA stages with an intermediate temporal pulse filtering for temporal contrast improvement. The scheme of Negative–Positive CPA amplification takes advantage of consecutive saturated amplification of down chirped and up chirped pulses. This allows a suppress imprint of gain narrowing, which usually limits the spectral bandwidth at the multi-terawatt power level, and reach the bandwidth in excess of 50 nm without using any direct spectral shaping of the pulse.

scholarly journals Accelerating ions with high-energy short laser pulses from submicrometer thick targets

2016 ◽  
Vol 4 ◽  
Author(s):  
F. Wagner ◽  
C. Brabetz ◽  
O. Deppert ◽  
M. Roth ◽  
T. Stöhlker ◽  
...  
Keyword(s):  
Focal Plane ◽  
Short Pulse ◽  
Laser Pulses ◽  
High Energy ◽  
Ion Acceleration ◽  
Temporal Contrast ◽  
Short Pulse Laser ◽  
Target Intensity ◽  
Short Laser Pulses ◽  
And Control

Using the example of the PHELIX high-energy short pulse laser we discuss the technical preconditions to investigate ion acceleration with submicrometer thick targets. We show how the temporal contrast of this system was improved to prevent pre-ionization of such targets on the nanosecond timescale. Furthermore the influence of typical fluctuations or uncertainties of the on-target intensity on ion acceleration experiments is discussed. We report how these uncertainties were reduced by improving the assessment and control of the on-shot intensity and by optimizing the positioning of the target into the focal plane. Finally we report on experimental results showing maximum proton energies in excess of 85 MeV for ion acceleration via the target normal sheath acceleration mechanism using target thicknesses on the order of one micrometer.

Control of Metal Alloy Oxidation with Electric Fields

1973 ◽  
Vol 31 ◽  
pp. 164-165
Author(s):  
R. R. Dils ◽  
P. S. Follansbee
Keyword(s):  
Electric Fields ◽  
Oxidation Process ◽  
Base Alloy ◽  
Oxide Surface ◽  
Platinum Electrodes ◽  
Insulating Layer ◽  
Iron Base Alloy ◽  
Alloy Oxidation ◽  
Aluminum Oxide Layer ◽  
And Control

Electric fields have been applied across oxides growing on a high temperature alloy and control of the oxidation of the material has been demonstrated. At present, three-fold increases in the oxidation rate have been measured in accelerating fields and the oxidation process has been completely stopped in a retarding field.The experiments have been conducted with an iron-base alloy, Pe 25Cr 5A1 0.1Y, although, in principle, any alloy capable of forming an adherent aluminum oxide layer during oxidation can be used. A specimen is polished and oxidized to produce a thin, uniform insulating layer on one surface. Three platinum electrodes are sputtered on the oxide surface and the specimen is reoxidized.

Evidence for a Blood Ganglion Barrier in the Superior Cervical Ganglion of the Rat

1982 ◽  
Vol 40 ◽  
pp. 204-204
Author(s):  
D. M. DePace
Keyword(s):  
Blood Vessels ◽  
Superior Cervical Ganglion ◽  
Peripheral Nerves ◽  
Time Schedule ◽  
Transmission Electron ◽  
Cervical Ganglion ◽  
The Central Nervous System ◽  
Cervical Ganglia ◽  
Capillary Circulation ◽  
And Control

The majority of blood vessels in the superior cervical ganglion possess a continuous endothelium with tight junctions. These same features have been associated with the blood brain barrier of the central nervous system and peripheral nerves. These vessels may perform a barrier function between the capillary circulation and the superior cervical ganglion. The permeability of the blood vessels in the superior cervical ganglion of the rat was tested by intravenous injection of horseradish peroxidase (HRP). Three experimental groups of four animals each were given intravenous HRP (Sigma Type II) in a dosage of.08 to.15 mg/gm body weight in.5 ml of.85% saline. The animals were sacrificed at five, ten or 15 minutes following administration of the tracer. Superior cervical ganglia were quickly removed and fixed by immersion in 2.5% glutaraldehyde in Sorenson's.1M phosphate buffer, pH 7.4. Three control animals received,5ml of saline without HRP. These were sacrificed on the same time schedule. Tissues from experimental and control animals were reacted for peroxidase activity and then processed for routine transmission electron microscopy.

Sign in / Sign up

Export Citation Format

Share Document