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81.
3 and β-BaB2O4 crystals. The power of the generated 214.5-nm light amounts to more than 100 μW. This light source will be used for laser cooling of Cd+ ions. Received: 4 August 1997/Revised version: 28 October 1997  相似文献   
82.
2 ) nonlinear crystal is reported. The device uses a standing-wave dual-resonator scheme to enhance both near-infrared lasers. For 7 mW of 778.2-nm and 275 mW of 842.5-nm input powers, 40 nW of 10.2-μm radiation is generated by a preliminary setup. A μW-level range output power is expected after optimization of the device optical components. This compact tunable source will allow Fabry–Pérot high-resolution Doppler-free spectroscopy of spherical molecules, such as OsO4 or SF6, in the 9–11 μm range as an alternative source to frequency-stabilized CO2 lasers. Received: 17 March 1998  相似文献   
83.
The magnetic susceptibility of Ce:Gd3Sc3Al3O12 (Ce:GSAG) and Ce:La3Lu2Ga3O12 (Ce:LLGG) has been studied in the temperature range from 15 to 293 K. Both the Ce-doped garnets Ce:GSAG and Ce:LLGG show anti-ferromagnetic ordering at 18 and 27 K, respectively. Crystal electric field split energy levels have been used to calculate the magnetic susceptibility following Van Vleck's model. The calculated susceptibility values reasonably agree with the experimental susceptibility data of Ce:LLGG but differ for that of Ce:GSAG system. Contribution from long-range ordering between Ce and Gd ions for anomaly in Ce:GSAG system is speculated.  相似文献   
84.
85.
We have developed a ring-cavity resonator that can be used to measure the absolute frequencies of optical transitions with an uncertainty below 40 kHz. The length of the resonator is calibrated against a reference laser locked to the D2 line of 87Rb, the frequency of which is known with 6 kHz accuracy. We demonstrate the power of this technique by measuring the absolute frequencies of various hyperfine transitions in the D1 line of 133Cs. Our results agree with earlier measurements using the frequency-comb technique, and have similar accuracy. Measurement of the D1-line frequency could lead to a more precise determination of the fine-structure constant. We also report a precise value of A=291.918(8) MHz for the hyperfine constant in the 6P1/2 state.  相似文献   
86.
The femtosecond photodissociation of CsI in the CsI-CH3CN complex has been studied. Recurrences are observed in the detection of the Cs+-CH3CN ion complex. They are assigned to the first vibrations of the Cs-NCCH3 bond formed after the CsI dissociation. This result is in good agreement with calculations on the similar NaI-CH3CN system which predict a linear structure for the ground state complex. Received 27 October 1999  相似文献   
87.
It is shown that the stepwise ionization of active organic molecules under UV pump radiation is responsible in a large part for poor lasing properties of dye-vapour active media as compared with liquid ones.  相似文献   
88.
4 as a nonlinear crystal and obtained a pump threshold of 7 mW and an output power of 6 mW for a pump power of 40 mW. The OPO operated in a single longitudinal mode pair of a signal and an idler, over 1 h without mode hopping in the free-running condition. The signal and the idler wavelengths were tunable by 1 nm by changing the crystal temperature by 20 °C. The continuous tuning of the beat frequency between the signal and the idler was achieved by temperature tuning (slow control, 80 MHz/K) and E-field tuning (fast control, 0.75 MHz/V). We demonstrated the feasibility of frequency control by phase locking the beat frequency. The beat frequency could be successfully phase locked to a signal generated by a synthesizer through the electrooptic effect of the crystal. The phase locking could be maintained over 1 h. Received: 27 January 1998/Revised version: 9 March 1998  相似文献   
89.
Precision spectroscopy on molecular tellurium is performed by measuring the frequency difference between the observed lines and an eigenfrequency of a high-finesse cavity mode. The mode frequency is derived from a measurement of the cavity's free spectral range taking into account the cavity dispersion due to phase shifts in the dielectric mirror coatings. The experimental technique is based on dual frequency modulation and is applied to determine the transition wavenumbers of several lines in130Te2 near 467 nm with an uncertainty of 2 × 10–8.  相似文献   
90.
The energy resolution of a VUV isochromat spectrometer employing the traditional energy selective Geiger counter can be significantly improved. The variance of the optical resolution function with the usual CaF2 entrance window is (240 meV)2. With SrF2 we obtain (113 meV)2 at room temperature and (73 meV)2 at 70°C. A direct confirmation of these data, which were derived from a moment analysis of the threshold behaviour of an Au isochromat is provided by a measurement of image potential states at Cu(001).  相似文献   
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