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111.
Carrier-envelope offset phase control: A novel concept for absolute optical frequency measurement and ultrashort pulse generation 总被引:5,自引:0,他引:5
H.R. Telle G. Steinmeyer A.E. Dunlop J. Stenger D.H. Sutter U. Keller 《Applied physics. B, Lasers and optics》1999,69(4):327-332
The shortest pulses periodically emitted directly from a mode-locked Ti:sapphire laser are approaching the two-optical-cycle
range. In this region, the phase of the optical carrier with respect to the pulse envelope becomes important in nonlinear
optical processes such as high-harmonic generation. Because there are no locking mechanisms between envelope and carrier inside
a laser, their relative phase offset experiences random fluctuations. Here, we propose several novel methods to measure and
to stabilize this carrier-envelope offset (CEO) phase with sub-femtosecond uncertainty. The stabilization methods are an important
prerequisite for attosecond pulse generation schemes. Short and highly periodic pulses of a two-cycle laser correspond to
an extremely wide frequency comb of equally spaced lines, which can be used for absolute frequency measurements. Using the
proposed phase-measurement methods, it will be possible to phase-coherently link any unknown optical frequency within the
comb spectrum to a primary microwave standard. Experimental studies using a sub-6-fs Ti:sapphire laser suggesting the feasibility
of carrier-envelope phase control are presented.
Received: 19 August 1999 / Published online: 8 September 1999 相似文献
112.
Received: 17 December 1998 相似文献
113.
SBS pulse compression to 200 ps in a compact single-cell setup 总被引:1,自引:0,他引:1
D. Neshev I. Velchev W.A. Majewski W. Hogervorst W. Ubachs 《Applied physics. B, Lasers and optics》1999,68(4):671-675
Received: 14 September 1998 / Published online: 24 February 1999 相似文献
114.
It is well known that saturating gain media can give rise to superluminal pulse propagation velocity. In most mode-locked
lasers the effect is unmeasurably small and has not yet been directly demonstrated. We present experiments on the initial
transient of an erbium fiber laser that show a dynamic shift in the propagation velocity to a value larger than the medium’s
linear group velocity as the pulse builds up.
Received: 14 December 1998 / Revised version: 21 May 1999 / Published online: 25 August 1999 相似文献
115.
Alina Bieńko Julia Kłak Jerzy Mroziński Rafał Kruszyński Dariusz C. Bieńko Roman Boča 《Polyhedron》2008
Two Re(IV)–Cu(II) heterometallic complexes {(CuLα)[ReCl4(ox)]}n (where Lα = N-meso-5,12-Me2-7,14-Et2-[14]-4,11-dieneN4), 1, and (CuLβ)[ReCl4(ox)] (Lβ = N-rac-5,12-Me2-7,14-Et2-[14]-4,11-dieneN4N-rac-5,12-Me2-7,14-Et2-[14]-4,11-dieneN4), 2, were synthesized. The [CuL2+] macrocyclic cation is coordinated from above and below by [ReCl4(ox)]2− units through the chloro-ligands and creates a chloro-bridged heterometallic ReIV–CuII one-dimensional zig-zag chain. Compound 2 can be viewed as a heterobimetallic dinuclear unit, in which the Re(IV)-Cu(II) centers are linked by an oxalato bridge. The magnetic behavior of 1 and 2 has been investigated over the temperature range 1.8–300 K. Compound 1 behaves like a ferrimagnetic {Re(IV)–Cu(II)} bimetallic, one-dimensional chain with intrachain antiferromagnetic coupling. Compound 2 shows a weak antiferromagnetic interaction within the [Re(IV)–Cu(II)] unit along with a strong single-ion anisotropy, D(Re) = −63 cm−1. 相似文献
116.
L. Fortunato R. M. Clark A. O. Macchiavelli R. Krücken 《The European physical journal. Special topics》2007,150(1):107-108
The critical point solution of the pairing phase transition
from vibrational to rotational regimes and an application to lead isotopes
are described. Suggestions on how to confirm the validity of the E(2) model
with transfer reactions using weakly-bound beams are discussed. 相似文献
117.
We have performed a comparative study of UV laser ablation of SrTiO3 with nanosecond- and sub-picosecond sources, respectively. The experiments were performed with lasers at a wavelength of 248 nm and pulse durations of 34 ns and 500 fs. Femtosecond ablation turns out to be more efficient by one order of magnitude and eliminated the known problem of cracking of SrTiO3 during laser machining with longer pulses. In addition, the cavities ablated with femtosecond pulses display a smoother surface with no indication of melting and well-defined, sharp edges. These effects can be explained by the reduced thermal shock effect on the material by using ultrashort pulses. 相似文献
118.
119.
F.G. Kondev M.A. Riley T.B. Brown R.M. Clark M. Devlin P. Fallon D.J. Hartley I.M. Hibbert D.T. Joss D.R. LaFosse R.W. Laird F. Lerma M. Lively P.J. Nolan N.J. O'Brien E.S. Paul J. Pfohl D.G. Sarantites R.K. Sheline S.L. Shepherd J. Simpson R. Wadsworth 《The European Physical Journal A - Hadrons and Nuclei》1998,2(3):249-251
The quadrupole moment for the πg
9/2⊗νh
11/2 band in the 130>Pr nucleus has been measured using the Doppler-shift attenuation method. A centroid shift analysis was carried out and a value
of Q0=6.1±0.4 eb, corresponding to an axial prolate deformation of β2=0.35(3), has been determined. This is the first direct experimental confirmation of the deformation-driving character of
the πg
9/2 orbital in an odd-odd nucleus in the A≃135 superdeformed region.
Received: 23 April 1998 相似文献
120.
The results of numerical modelling of cascaded compression of the first and second Stokes pulses during regenerative regime of the forward transient stimulated Raman amplification are presented for the case when the walk-off length of the first Stokes pulse due to group velocity mismatch is shorter than the length of the nonlinear medium. The influence of the initial amplitudes of the seed first Stokes pulses, its durations and its time delay with respect to the pump pulse, the Kerr nonlinearity of the medium on the conversion efficiency, duration and propagation factor M2 of the first and second Stokes pulse are studied. It is demonstrated that for the pump pulse duration of 1 ps the duration of the compressed second Stokes pulses in a KGW crystal near the beam axis may be approximately 14 times shorter than the pump pulse duration. It is shown that the propagation factor of the compressed pulses increases significantly because of complex spatial-temporal dynamics of compression and the influence of Kerr nonlinearity of Raman medium. 相似文献