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11.
Step-selective measurement by grating-based lateral shearing interferometry for segmented telescopes
We present an original step-selective mode which allows to measure only the steps and not the slowly varying aberrations of a wave front. This mode can be implemented when measuring segmented wave front by a diffraction-grating-based lateral shearing interferometer. This set-up rests on the different chromatic response of these interferometers depending on the rate of change of the impinging wave front: for smooth defects, the response is classically achromatic whereas it is chromatic for a step variation, which was to our knowledge overlooked. The interest of this mode for astronomical measurements is highlighted. First we present theoretical considerations to show how this mode of measure is possible; then a numerical simulation illustrates them. 相似文献
12.
Doppler-broadened atomic and molecular spectra were observed with a one octave tunable, continuous-wave, doubly resonant, monolithic optical parametric oscillator (OPO) using 5% MgO-doped LiNbO3 as a non-linear crystal with a birefringent phase-matching configuration. By tuning the frequency of a pump laser, longitudinal mode selection over 20 successive modes, corresponding to a 60 GHz span, was possible, owing to the simple structure of the monolithic OPO. Continuous frequency tuning was achieved using an external waveguide-type electrooptic phase modulator (EOM). By changing the modulation frequency of the EOM, frequency tuning of the optical sidebands over 12 GHz was possible, which is larger than the one free spectral range of the monolithic cavity of 3 GHz. We could observe the Cs-D1 (894 nm), Cs-D2 (852 nm), Rb-D1 (795 nm), acetylene R9 (1520 nm) and P9 (1530 nm) transitions with the single monolithic OPO. 相似文献
13.
Effect of laser fields on Na2 interaction potentials is studied by calculating the time-resolved photoelectron spectrum (TRPES) with the time-dependent wave-packet method. It is shown that the photoelectron spectrum at different delay times reflects the population in different electronic states. We inspect the periodicity of vibrational motion in neutral states, and map the vibrational wave-packet propagation in corresponding internuclear coordinate. 相似文献
14.
Fugui Yang Chaoyang Tu Jianfu Li Hongyan Wang Yanping Wei Zhenyu You Yan Wang 《Journal of luminescence》2007,126(2):623-628
Good quality crystals ZnWO4 activated with Er3+ have been grown by means of Czochralski method and characterized using optical spectroscopy techniques. XRD, absorption spectra, fluorescence spectrum are presented and the Judd-Ofelt intensity parameters Ω2, Ω4, and Ω6 are obtained to be 6.76×10-20, 0.37×10-20, and 0.50×10-20 cm2, respectively. Along crystallographic axes, refractive indices are presented. The fluorescence decay time of the 4I13/2 level has also been investigated and shows an exponential behavior with a lifetime value of 5.52 ms. The crystal is potentially used for green and infrared eye-safe lasers. 相似文献
15.
Semi-quantitative time resolved LIBS measurements 总被引:1,自引:0,他引:1
R. Barbini F. Colao R. Fantoni A. Palucci S. Ribezzo H.J.L. van der Steen M. Angelone 《Applied physics. B, Lasers and optics》1997,65(1):101-107
Received: 2 February 1996/Accepted: 20 January 1997 相似文献
16.
The electronic band structure of YbRhSn has been calculated using
the self-consistent full potential nonorthogonal local orbital minimum
basis scheme based on the density functional theory. We investigated
the electronic structure with the spin-orbit interaction and on-site
Coulomb potential for the Yb-derived 4f orbitals to obtain the correct
ground state of YbRhSn.
The exchange interaction between local f electrons and conduction
electrons play an important role in the heavy fermion characters of them.
The fully relativistic band structure scheme
shows that spin-orbit coupling splits the 4f states
into two manifolds, the 4f7/2 and the 4f5/2 multiplet. 相似文献
17.
T.M. Di Palma A. Latini M. Satta A. Giardini-Guidoni 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》1998,4(2):225-229
A photoionization study of the Me(NH3) clusters formed in the reaction of photoablated third group metal vapor with gaseous ammonia is reported. The photoionization
spectra exhibit some features due to vibrational excitation of ionic clusters and to transitions to neutral Rydberg states
leading to autoionization. DFT quantum chemical calculations are performed on the Me(NH3). The cluster geometries are fully optimized imposing the C3v symmetry. The calculated values of the IPs are in agreement with those experimentally determined.
Received: 16 February 1998 / Revised and Accepted: 7 May 1998 相似文献
18.
L. S. Ma Ph. Courteille G. Ritter W. Neuhauser R. Blatt 《Applied physics. B, Lasers and optics》1993,57(3):159-162
Modulation-transfer spectroscopy is used to observe resonances in 130Te2 near 467 nm. A signal-to-noise ratio of 500 is obtained with 1 mW laser power and with a time constant of 10 ms; the lineshapes are investigated in detail for different demodulation phases. The signal can be used to servolock a blue dye ring laser at 467 nm on a 130Te2 resonance which serves as reference line for precision spectroscopy on single, trapped Yb+ ions at 467 nm. 相似文献
19.
M. Jackson B. Chuzles C. Dirocco P. Noffke L. R. Zink 《Applied physics. B, Lasers and optics》2005,80(8):945-947
A three-laser heterodyne system has been used to measure the frequencies of four previously observed far-infrared laser emissions generated by optically pumping either hydrazine (N2H4) or its fully deuterated isotope (N2D4) with a continuous-wave carbon dioxide laser. These newly measured frequencies have fractional uncertainties of ± 2 × 10−7 and correspond to laser wavelengths ranging from 63.9 to 158.4 μm. This work represents the first measurement of a N2D4 laser frequency. 相似文献
20.
An optical tilt sensor was developed and its performance was investigated. The tilt sensor set-up consisted of a laser light source, lenses and an image sensor. A precision reference tilt sensor was also installed on the same stage, and the measurement results of tilt angles using the optical and reference tilt sensors were correlated. The correlation coefficient (R-value) obtained under ideal conditions was 0.99454, indicating that the optical tilt sensor could produce as accurate measurements as the precision reference tilt sensor. The R-value decreased to 0.97714 and 0.93209 when the image sensor was shifted backwards and forwards from the focal plane by 1 mm, respectively. The R-value decreased to 0.96840 when the tilt sensor was performed with the room light turned on. There were not significant differences in the measurement results obtained with air conditioners turned on and off, indicating that the optical tilt sensor was robust and was not sensitive to the surrounding air turbulence. These findings are useful for the final design of the optical tilt sensor. 相似文献