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1.
H. R. Telle 《Applied physics. B, Lasers and optics》1984,35(4):195-198
Low-threshold tunable cw laser oscillation is achieved at the4
F
3/24
I
13/2 transition of NdP5O14. Continuous tunign over 1.8% of the central wavelenght is possible with 55 mW of absorbed pump power. At gain line maximum near 1.32 , the output power exceeded 1 mW. Pump threshold as low as 8 mW was observed. Reliable cw operation of the 1.3 m NdP5O14 laser pumped by a 15 mW AlGaAs laser diode is demonstrated. 相似文献
2.
Rainer Telle Ai Momozawa Jochen M. Schneider 《Journal of solid state chemistry》2006,179(9):2850-2857
MAX-phases being usually composed of transition metals, group A elements and carbon/nitrogen are considered interesting materials for many applications because of their tremendous bulk modulus, “reversible” plasticity, and machinability. This is mainly due to their unique kind of bonding comprising covalent, ionic as well as metallic bonds providing “easy” planes of rupture and deformability due to the layered crystal structures.In transition metal boride systems, similar types of bonding are available. In particular the W2B5-structure type and its stacking variations allow the synthesis of strongly layered crystal structures exhibiting unique delamination phenomena.The paper presents ab initio calculations showing the similarities of bonding between the ternary carbides and the corresponding ternary or quaternary borides. Formation of boride-based nano-laminates from auxiliary liquid phases, from the melt as well as during sintering and precipitation from supersaturated solid solutions will be discussed by means of SEM and TEM studies. The role of impurities weakening the interlayer bonding will be addressed in particular. The pronounced cleavage parallel to the basal plane gives rise for crack deflection and pull-out mechanisms if the laminates are dispersed in brittle matrices such as boron carbide, silicon carbide or other transition metal borides. 相似文献
3.
We developed a novel technique for frequency measurement and synthesis, based on the operation of a femtosecond comb generator as transfer oscillator. The technique can be used to measure frequency ratios of any optical signals throughout the visible and near-infrared part of the spectrum. Relative uncertainties of 10(-18) for averaging times of 100 s are possible. Using a Nd:YAG laser in combination with a nonlinear crystal we measured the frequency ratio of the second harmonic nu(SH) at 532 nm to the fundamental nu(0) at 1064 nm, nu(SH)/nu(0) = 2.000 000 000 000 000 001x (1 +/- 7x10(-19)). 相似文献
4.
U. Brinkmann H. Busse K. Pippert H. Telle 《Applied Physics A: Materials Science & Processing》1979,18(3):249-255
A gasdynamic jet is described, which carries excited metal atoms in subsonic or supersonic flow. The excitation is performed
by a hot hollow cathode discharge. The jet expands parallel into an atmosphere of a few mbar. Its use will be in atomic and
molecular spectroscopy, in chemistry and spectroscopy of free radicals, and in electronic-transition chemical laser design. 相似文献
5.
The generation and characterization of femtosecond pulses at three independently tunable visible wavelengths is reported. Selected spectral portions of a common continuum generated in sapphire are amplified in noncollinear optical parametric amplifiers. The phase relation of the pulse trains is analyzed with a nonlinear interferometer based on coherent anti-Stokes Raman scattering and is found to be locked to better than 250 mrad rms. Small spectral shifts of the pulses lead to interference behavior that is consistent with 1 kHz frequency combs. 相似文献
6.
A novel method is described for fast frequency modulation or frequency control of diode lasers that avoids problems associated with bias current modulation, namely, amplitude modulation and thermal phase delays. The method is based on amplitude-modulated, noninterfering control light with a wavelength near the transparency region of the laser diode, which specifically modifies the spectral gain profile to yield a constant gain but a controllable refractive index at the lasing wavelength. This permits amplitude-modulation-free frequency modulation at modulation frequencies up to the relaxation oscillation frequency. A phase lock between the emissions of two extended-cavity diode lasers that could not be achieved with bias current modulation was achieved by this method. 相似文献
7.
8.
U. Brinkmann W. Hartig H. Telle H. Walther 《Applied Physics A: Materials Science & Processing》1974,5(2):109-115
The isotope specific two-step photoionization of metastable Ca atoms was investigated using a continuous wave dye laser and
an Ar+ laser. The photoionization was performed via a transition to an autoionizing state. Therefore an ionization probability as
high as 10−2 could be obtained. 相似文献
9.
Using a recently developed electronically tunable cw dye laser, the spectrum of an absorption sample could be obtained and repeatedly scanned every 10 μsec. The system is potentially capable of monitoring spectral changes in times as short as 10?7 sec. 相似文献
10.
Linewidth measurements of the ν2 + ν4 R+(29) A14 + E9 + F114 absorption at 1073.279 cm−1 were made in the pressure range of 0.5 to 50 Torr CF4. The data, after correction for Doppler broadening, reduce to a self-broadening coefficient of 10.8 ± 0.4 MHz/Torr. Comparisons of the linewidth for pure CF4 with the linewidth of an Ar-CF4 mixture and with the prediction of the hard-sphere, gas-kinetic model imply a relaxation mechanism that is not dominated by a resonant (V-V) process, and has an effective cross section that is intermediate in size between the cross sections associated with dipole-dipole and hard-sphere collisions. 相似文献