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Topic: Femtosecond

	Lightwave - Dispersion testing using a femtosecond PMD analyzer
		One approach to PMD testing is to use a femtosecond PMD analyzer.
		The femtosecond PMD analyzer was used to test PMD in several fiber spools and installed optical networks.
		The technique used in the femtosecond PMD analyzer consists of measuring Stokes vectors from the Fourier spectra.
	lw.pennnet.com /Articles/Article_Display.cfm?Section=Articles&Subsection=Display&ARTICLE_ID=168650 (1298 words)

	Femtosecond -- Facts, Info, and Encyclopedia article (Site not responding. Last check: 2007-10-26)
		A femtosecond is the (A tetravalent nonmetallic element; next to oxygen it is the most abundant element in the earth's crust; occurs in clay and feldspar and granite and quartz and sand; used as a semiconductor in transistors) SI unit of time equal to 10
		The word femtosecond is formed by the (An affix that added in front of the word) prefix femto and the (An organization regarded as part of a larger social group) unit second.
		For a list of times on the order of 1-10 femtoseconds, compare (Click link for more info and facts about 1 E-15 s) 1 E-15 s.
	www.absoluteastronomy.com /encyclopedia/f/fe/femtosecond.htm (154 words)

	Femtosecond Optical Tweezers (Site not responding. Last check: 2007-10-26)
		Femtosecond lasers can thus be used for optical tweezing and simultaneously utilized to induce nonlinear multi-photon processes such as two-photon excitation or even photoporation.
		It is clearly evident that, as both laser regimes imply a Q-value within experimental error of each other, femtosecond optical tweezers are just as effective as cw optical tweezers, and that it is the average power of the laser source (rather than the peak power) that dominates the optical trapping force.
		To demonstrate this, we used the femtosecond titanium-sapphire laser operating at a centre wavelength of 800 nm to achieve simultaneous two-photon fluorescence excitation and femtosecond optical tweezing of fluorescent polymer microspheres (d = 1.0 ?m).
	www.st-andrews.ac.uk /~atomtrap/Research/Femto/femto.htm (1657 words)

	Femtosecond Pulses At Berkeley Lab's Advanced Light Source
		Other co-authors are Berkeley Lab director and femtosecond spectroscopy pioneer Charles Shank, Swapon Chattopadhyay of the CBP, Thornton Glover and Philip Heimann of the ALS, and H.H.W.Chong, a graduate student at the University of California at Berkeley.
		Schoenlein and his colleagues produced their femtosecond pulses by sending a burst of light from a femtosecond optical laser through a wiggler insertion device at the same time as the electron bunches that make up the storage ring beam passed through it.
		Creating femtosecond x-rays at the ALS won't interfere with other experiments at the facility as only a small fraction of the electron bunches in the storage ring beam are modulated by the laser and the beam quickly recovers.
	www.lbl.gov /Science-Articles/Archive/femto-xrays.html (1052 words)

	Femtosecond (Site not responding. Last check: 2007-10-26)
		The "slit" was a crafted femtosecond pulse consisting of one-and-a-half cycles--say, two maxima and one minima--passed through an argon gas.
		They then passed a femtosecond laser beam, which was polarised perpendicular to the plane of incidence, through the prism onto the surface of the mercury (see...
		Her femtosecond laser emits light in the near infrared range at a wavelength that the human eye can barely see.
	ntalert.com /nanotechnology_news/Femtosecond.html (601 words)

	OFC 2004 - Chromium: Forsterite Femtosecond Laser from Del Mar Ventures by Del Mar Ventures (Site not responding. Last check: 2007-10-26)
		The femtosecond Cr:F laser system is a mode-locked ultrashort laser producing pulses in the near-infrared ~1250 nm range.
		With their high bandwidth and short pulse duration, Cr:F femtosecond lasers are being used in a rapidly growing number of applications, including ultrafast photochemistry, photophysics, photoablation and micromachining.
		Femtosecond lasers are being used to write subsurface wave guides and to induce index changes in optical fibers.
	www.photonics.com /tradeshows/OFC2004/XQ/ASP/psID.53/QX/showcasedisplay.htm (237 words)

	Femtosecond Time-Resolved Laser Induced Desorption of Positive Ions from MgO (Site not responding. Last check: 2007-10-26)
		For these reasons, femtosecond laser studies are needed to clarify the role of ultrafast phenomena involved in laser desorption processes.
		The positive ion mass spectrum is determined as a function of the temporal delay between two equivalent sub-threshold UV femtosecond pulses impinging upon a cleaved MgO crystal.
		Femtosecond UV pulses are produced in an amplified titanium-sapphire (Ti:sapphire) based laser system operating at a fundamental wavelength of 795 nm.
	www.emsl.pnl.gov /docs/csd/annual_report1999/1578b_3a.html (1089 words)

	Femtosecond (Site not responding. Last check: 2007-10-26)
		The clusters were then studied using a combination of femtosecond laser light and time-resolved photoelectron imaging.
		A wide-bandwidth, phase-stabilized femtosecond laser is used to monitor the real-time dynamic evolution of population transfer.
		Reid is using femtosecond pulses of a 1530nm laser to probe the chip, and employing a so-called solid immersion lens (SIL) to artificially increase the half...
	www.ntalert.com /nanotechnology_news/2005_01/Femtosecond.html (272 words)

	Femtosecond Imaging
		The femtosecond Cr:Forsterite (Cr:F) laser system from Del Mar Ventures is a mode-locked ultrashort laser producing pulses in near infrared ~1250 nm range.
		Femtosecond lasers are being used in a rapidly growing number of applications, including ultrafast photochemistry, photophysics, photoablation, micromachining, imaging condensed matter, semiconductor device physics, and other areas.
		The femtosecond Cr:Forsterite laser is tunable over wavelengths from 1230 to 1270 nm, making it ideal for imaging condensed matter and biomedical applications.
	www.sciner.com /FS/fs_imaging.htm (1161 words)

	Industrial Laser Solutions - Femtosecond lasers for manufacturing
		Femtosecond laser ablation of materials initially has been carried out in vacuum.5 Recent efforts have shown that ablation in ambient air can be achieved with similar results,4 thereby removing another hurdle to the acceptance of the technology.
		The availability of a turnkey amplified system resulted in the first (published) industrial femtosecond micromachining application as a dielectric mask repair tool used in photolithography replacing the pulsed Nd:YAG laser.6 The ultrashort pulses enabled removal of selected chromium layers on the mask without affecting the optical transmission of the dielectric substrate.
		Femtosecond lasers are available from a number of manufacturers in the U.S. and Europe.
	ils.pennnet.com /Articles/Article_Display.cfm?Article_ID=144191 (1002 words)

	Physics News Update
		Femtosecond lasers for cutting and imaging brain tissue have been demonstrated in a research collaboration that includes physicists and pharmacologists.
		Used widely in clinical settings (e.g., to examine biopsied tissue from a suspected breast tumor) and in biological research (e.g, to study the anatomy of muscle), histology is presently a manual process, requiring a skilled technician to slice frozen tissue samples into thin pieces, and then view them with an optical microscope.
		Since the femtosecond technique completely destroys its tissue samples, it may not be appropriate for certain clinical applications such as biopsies of breast tissue, as physicians may wish to preserve the tissue for future reference.
	www.aip.org /pnu/2003/split/640-1.html (430 words)

	Ophthalmology Times - Femtosecond laser superior for ring segment channels
		Of the 50 mechanical procedures, the goal was for distance in 35 and for near in 15; in the femtosecond laser group, 10 procedures targeted a distance goal and two targeted near.
		At 3 months UCVA was 20/20 or better in 49% of patients in the mechanical group versus 86% in the femtosecond laser group, and all of the latter patients versus 86% of those with mechanically created channels had 20/40 or better vision.
		Neatrour noted that although use of the femtosecond laser for channel centration minimizes the surgeon-dependent factor, achieving good centration is still critical.
	www.ophthalmologytimes.com /ophthalmologytimes/article/articleDetail.jsp?id=73393 (729 words)

	Femtosecond Laser Stabilization: Time and Frequency Domain Applications
		The stabilization of mode-locked femtosecond lasers has played a key role in recent advances in optical frequency measurement [1,2], carrier-envelope phase stabilization [3,4], all-optical atomic clocks [5,6] and coherent pulse synthesis [7].
		However, because of the higher peak intensities of femtosecond pulses and the dynamics of the mode-locking process itself, they are much more susceptible to frequency noise induced by pump amplitude fluctuations.
		Actuators commonly used to stabilize femtosecond lasers are usually limited to ~50 kHz (piezoelectric translation) for control of the cavity length to ~100 kHz (modulation of the pump beam intensity via acousto-optic modulation) for control of the carrier and offset frequencies.
	www.ieee.org /organizations/pubs/newsletters/leos/Oct03/fem_laser.html (1800 words)

	Femtosecond Laser Project (Site not responding. Last check: 2007-10-26)
		A detailed schematic of the femtosecond laser facility is shown in Figure 1.
		A femtosecond mode-locked seed beam of 14.5 nm bandwidth, pulse energies in the nanojoule range and repetition rate of 80 MHz is emitted from a Ti:sapphire oscillator pumped by a diode laser.
		It has been thought that femtosecond pulsed laser recrystallization is not so desirable because the pulse duration is so short for crystallization.
	www.me.berkeley.edu /ltl/research/fs.html (1325 words)

	Laser Time Slicing
		At the heart of the proposal was the use of a high-power, femtosecond laser synchronized with the electron bunches so that a pulse of laser light passed collinearly with an electron bunch through an undulator or wiggler.
		Lasers with pulses of 100 femtoseconds (0.1 trillionths of a second) or less have been available for infrared and visible light but so far not for x rays.
		To verify the femtosecond time structure, they first imaged visible light from Beamline 6.3.2 onto a nonlinear optical crystal along with a delayed 50-fs cross-correlation pulse from the laser system.
	www-als.lbl.gov /als/science/sci_archive/femto2.html (860 words)

	Hot Flashes, Cold Cuts: Science News Online, Nov. 16, 2002 (Site not responding. Last check: 2007-10-26)
		Because their pulses are so brief, some of the new, femtosecond lasers are rated equal—for a fleeting instant—to all the world's power plants put together.
		Femtosecond lasers are delicate enough for eye surgery because their high-power, but low-energy pulses only take little nips of materials.
		Laser specialists say that other promising uses of femtosecond lasers, such as drilling fuel-injector nozzles in steel, are being held back because today's lasers are too slow and too costly.
	www.sciencenews.org /20021116/bob9.asp (2409 words)

	Femtosecond Intralase Laser Eye Surgery from Optimax, the UK 's No.1 laser eye clinic
		These should be substantially improved upon when Intralase Femtosecond and Wavefront becomes the norm for suitable patients both in the number who achieve 20:20 or better vision and the reduction in complications.
		It is for this reason that Intralase Femtosecond gives better result with standard (non Wavefront) treatment than Wavefront treatments with a flap created by a blade.
		A major benefit of Intralase Femtosecond is that it is much more precise than a blade and therefore it can cut the flap at a position very close to the top surface of the cornea.
	www.optimax.co.uk /default.aspx?page=7349 (896 words)

	Femtosecond laser technique opens new opportunities for research on neural regeneration
		SANTA CRUZ, CA--In a breakthrough for research on nerve regeneration, a team of scientists has reported using femtosecond laser pulses to precisely cut individual axons of nerves in the roundworm Caenorhabditis elegans, one of the most versatile and widely used experimental organisms for genetic and biomedical research.
		Ben-Yakar initiated a femtosecond laser nanosurgery project two years ago at Stanford and is currently an assistant professor of mechanical engineering at the University of Texas at Austin.
		The duration of the laser pulses used in the study was 200 femtoseconds (a femtosecond is a millionth of a billionth of a second), and the pulses were delivered at a rate of one thousand per second.
	www.eurekalert.org /pub_releases/2004-12/uoc--flt121304.php (1172 words)

	Femtosecond laser products from Del Mar Photonics
		Del Mar Photonics offers integration of femtosecond laser systems for multiphoton imaging, scanning probe microscopy, micromachining, molecular dynamic, X-ray and plasma research, THz generation and spectroscopy and other applications.
		Femtosecond up-conversion studies of thermo photovoltaic photoluminescence of heavily doped semiconductor samples
		Let's discuss your micromachining needs and how our femtosecond amplifier systems Teahupoo and Wedge based on Ti:Sapphire and Pipeline based on Cr:Forsterite systems can be integrated in your future micromachining instrumentation.
	www.femtosecondsystems.com (541 words)

	LaserMyEye :: Encyclopedia :: Femtosecond laser
		A solid state laser which uses ultrashort infrared light pulses for direct intrastromal tissue interaction.
		Femtosecond lasers are increasingly being used as an alternative to mechanical microkeratomes in the creation of the LASIK flap.
		Femtosecond lasers are also being used for corneal transplantation as a possibly more precise alternative to mechanical microkeratomes.
	www.lasermyeye.org /encyclopedia/femtosecond.html (117 words)

	Press Release: The 1999 Nobel Prize in Chemistry
		Scientists the world over are studying processes with femtosecond spectroscopy in gases, in fluids and in solids, on surfaces and in polymers.
		With femtosecond spectroscopy we can for the first time observe in 'slow motion' what happens as the reaction barrier is crossed and hence also understand the mechanistic background to Arrhenius' formula for temperature dependence and to the formulae for which van't Hoff was awarded his Nobel Prize.
		In femtosecond spectroscopy the original substances are mixed as beams of molecules in a vacuum chamber.
	www.nobel.se /chemistry/laureates/1999/press.html (2465 words)

	RESEARCHERS OBTAIN FIRST FEMTOSECOND X-RAY BEAMS
		A femtosecond is to one second in duration what one second is to 30 million years.
		With femtosecond x-ray pulses, it would be possible, for example, to track the movement of atoms in a sample of material during a phase transition (solid to liquid to gas), a chemical reaction, or any other process of physical change.
		Once femtosecond pulses of x-rays are generated, a magnet is used to remove the electron beam.
	www.lbl.gov /Science-Articles/Archive/first-femtosecond-beam.html (619 words)

	Femtosecond Surface Dynamics
		The temporal evolution is followed using a second interrogating femtosecond (probe) pulse, that does not perturb the system.
		This probe pulse can be variably delayed with respect to the pump pulse, so that spectroscopic surface images can be recorded at pre-selected times after initiation of the surface process by the pump pulse.
		The technique of Femtosecond Sum-Frequency Generation (fs-SFG) relies on the non-linear optical phenomenon that, at a surface, the frequencies of two light fields can be added up to make a new field (with a new colour).
	wwwchem.leidenuniv.nl /surfcat/html/femtosec.html (2270 words)

	Batteries power femtosecond laser (June 2002) - News - optics.org
		A portable diode-pumped femtosecond laser developed by a research team at the University of St Andrews, UK, has an electrical-optical efficiency of 4 % (Optics Communications 205 207).
		The researchers say that their system has the potential to open up femtosecond laser applications that have so far been hindered by the large size and high cost of its predecessors.
		It could be used as a compact source for generating broad continuum light in photonic crystal fibres, and as an efficient source of ultrashort pulses in the blue region.
	optics.org /articles/news/8/6/11/1 (437 words)

	BCP/Ultrafast: The Femtosecond research Centre
		Many groups in the world work on femtosecond (ultrafast) spectroscopy and a (short) list of links to groups can be found under ultrafast links.
		The Ultrafast group's interests are femtosecond chemical physics experiments and the development of novel techniques such as fs electron pulses and terahertz (THz) pulses.
		For example, high-power ultrafast lasers are used to produce femtosecond electron pulses for the study of dynamics on surfaces.
	dutch.phys.strath.ac.uk /FRC (931 words)

	Femtosecond Laser Micromachining / Instrumentation Division / Ultrafast Laser Laboratory / Page10 (Site not responding. Last check: 2007-10-26)
		Using femtosecond rather than picosecond or nanosecond light pulses, laser energy is deposited into small volumes by multiphoton nonlinear optical absorption followed by avalanche ionization.
		Perhaps the most encouraging of all, clinical trial of femtosecond laser eye surgery on human is now in progress.
		Despite of the various potential applications of femtosecond laser micromachining, the precise mechanism of the process is still under investigation.
	www.inst.bnl.gov /LaserLab/page10.html (623 words)

	Quantum - Femtosecond Laser
		You’ll have to be quick because it usually happens on the scale of femtoseconds (10^-15 of a second).
		the moon in one second, in 50 femtoseconds it can't even travel the width of a human hair.
		Femtosecond laser research is truly in its’ infancy and the potential applications are only just being guessed at.
	www.abc.net.au /quantum/stories/s141195.htm (533 words)

	Technology > Micromachining
		In other words, a femtosecond is a million times shorter than a nanosecond.
		A femtosecond is more than a million times shorter than the several nanosecond duration pulses used in traditional industrial lasers micromachining systems.
		These systems routinely deliver 5 to 10 Gigawatts of peak power (this is more than the average power delivered by a large nuclear plant).The laser intensity easily reaches the hundreds of Terawatts per square centimeter range at the work spot.
	www.phoco.com /internet/tech_micromachining.html (1770 words)

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