共查询到20条相似文献,搜索用时 615 毫秒
1.
Beach R. Shinn M.D. Davis L. Solarz R.W. Krupke W.F. 《Quantum Electronics, IEEE Journal of》1990,26(8):1405-1412
A spectroscopic investigation of the biaxial crystal yttrium orthosilicate doped with Nd3+(Nd3+:Y2SiO5) has been performed. Spectrally and orientationally resolved emission cross sections necessary for the evaluation of laser performance on the Nd3+ 4F 3/2-4I 9/2 and 4F 3/2-4I 11/2 transitions have been determined. The Judd-Ofelt theory has been applied to measured values of optical absorption line strengths to obtain the orientation averaged intensity parameters: Ω2-3.34×10-20 cm2, Ω 4=4.35×10-20 cm2, and Ω6=5.60×10-20 cm2. These Judd-Ofelt intensity parameter values are significantly different from those previously reported by A.M. Tkachuk et al. Using these intensity parameters, the Nd3+ 4F 2 metastable state lifetime is predicted to be 225 μs. Measured low Nd concentration 4F 3/2 lifetimes of 214 μs indicate a high radiative quantum efficiency. Because of the Stark level splitting of the Nd3+ 4F 3/2 and 4I 9/2 manifolds, laser operation at twice one of the Cs atomic resonance filter acceptance wavelengths is possible 相似文献
2.
A report is presented of the thermal shifts of eleven of the twelve lines from the 4F 3/2 Stark energy levels to the 4I 11/2 energy levels in an Nd:YAG laser for a temperature change from 20-200°C. The thermal shift difference between the Stark sublevels R 1, R 2 in 4F 3/2 is found to be about -0.6±0.6 cm-1/100°C. Within experimental uncertainty, all of the lasing lines either moved to longer wavelength or remained unchanged with increasing temperature 相似文献
3.
A generalized model for 3-μm (4I 11/2 →4I 13/2)Er lasers is proposed. The essential energy transfer processes present in the single-doped Er 3+ systems (up-conversion from 4I 13/2, up-conversion from 4 I 11/2, cross-relaxation from 4S 3/2), as well as those present in Cr3+ codoped Er 3+ systems, are taken into account. In the frame of this model, the main features of 3 μm Er3+ lasers, such as long pulse or CW operation, the change of emission wavelength as a function of pumping conditions, and the effects of codoping with Ho3+ or Tm3+ ions, are explained 相似文献
4.
Percival R.M. Phillips M.W. Hanna D.C. Tropper A.C. 《Quantum Electronics, IEEE Journal of》1989,25(10):2119-2123
The fluorescence spectrum of praseodymium in a silica host has been investigated through the direct excitation of the 3P 0, 1D 2, and 1G 4 absorption bands, which occur at around 488, 590, and 974 nm, respectively. The observed spontaneous emission consists of four main bands with peaks at 633, 707, 888, and 1080 nm. In each case the level principally responsible for these emissions was found to be 1D 2. Stimulated emission has been seen for the first time at 888 nm for a threshold of 10 mW absorbed power. In addition, the lasing characteristics at 1080 nm have been investigated 相似文献
5.
Woodward J.R. Cobb S.H. Shen K. Gole J.L. 《Quantum Electronics, IEEE Journal of》1990,26(9):1574-1587
Evidence is obtained which demonstrates the potential for developing purely chemical visible lasers based on rapid near-resonant energy transfer from metastable excited triplet states of germanium and silicon monoxide (a 3Σ+,b 3Π) to select metal atoms. In this study, the Group IIIA metal atoms were chosen as the energy receptors for the energy transfer-pump sequence. Excited triplet states were generated from the Ge-O3, Ge-N2, Si-N2O, and Si-NO2 reactions; the bulk of the experimental results was obtained with a germanium-based system. The energy stored in the long-lived triplet states is transferred to pump X 2P 1/2 thallium, indium, and gallium atoms to their lowest lying 2 S 1/2 states. The authors observe a system of temporal behavior which suggests the creation of a population inversion producing a gain condition and forming the basis for full cavity oscillation on the Tl 72S 1/2-6P 3/2 transition at 535 nm 相似文献
6.
Stimulated anti-Stokes Raman scattering at 145.7 nm in inverted Se is generated by photolysis of OCSe at 193 nm and the subsequent up-conversion of 205.1-nm pump radiation. The tuning profile is characterized with OCSe pressure, the energies and relative timing of the pump and photodissociation lasers, and CO and Ar buffer-gas pressure. The use of CO as a buffer gas is discovered to be detrimental to the anti-Stokes output. Sixteen competing stimulated emission channels are found to suppress anti-Stokes emission on exact 4p 4 1S 0-4p 3 5s 3 P 01 pump resonance 相似文献
7.
A Dy:YLF laser operating on the 6H 11/2 to 6H 13/2 transition at 4.34 μm and using a laser pumping scheme is reported. This pumping scheme is necessitated by the short upper-laser-level lifetime and the small effective stimulated-emission cross section. A suitable laser for this application is the Er:YLF laser operating at 1.73 μm. A simple model that approximates Dy:YLF laser performance well is presented. Results on laser performance, including a determination of the slope efficiency and threshold as a function of the output mirror reflectivity and a correlation of the pulse length with the laser output energy, are reported. Overall laser efficiency is found to be limited primarily by the ratio of the pump wavelength to laser output wavelength and the terminated four-level laser operation 相似文献
8.
Hong-Yuan Shen Zeng R.R. Yu-Ping Zhou Yu G.F. Cheng-Hui Huang Zheng-Dong Zeng Zhang W.J. Ye Q.J. 《Quantum Electronics, IEEE Journal of》1991,27(10):2315-2318
The oscillation condition of a simultaneous multiple wavelength laser has been established and used to analyze the possibility of simultaneous oscillation in various neodymium host crystals, such as Nd:YAG, Nd:YLF, Nd:BEL, and Nd:YAP crystals at the transitions from 4F 3/2-4I 13/2 and 4F 3/2-4I 11/2. It is shown that this kind of laser can be realized in all the described crystals in a pulsed state. In general, continuous wave (CW) operation, however, can only be achieved for Nd:YAP. On the basis of these results, CW simultaneous double wavelength lasing has been achieved in a Nd:YAP crystal for the first time at both 1.0795 μm and 1.314 μm 相似文献
9.
10.
Rabinovich W.S. Bowman S.R. Feldman B.J. Winings M.J. 《Quantum Electronics, IEEE Journal of》1991,27(4):895-897
The tuning characteristics of the 5I 6 -5I 7 transition in a Ho:YAlO3 laser, intracavity pumped by a 1.079 μm Nd:YalO3 laser, were studied. Operation on seven distinct lines between 2.844 and 3.017 μm was found, and the threshold and relative slope efficiency of each line was measured. Several of these lines were previously unreported 相似文献
11.
Gruneisen M.T. MacDonald K.R. Gaeta A.L. Boyd R.W. Harter D.J. 《Quantum Electronics, IEEE Journal of》1991,27(1):128-134
Energy transfer between two laser beams of comparable intensity due to their nonlinear interactions in an atomic vapor was investigated. Strong coupling occurs due to stimulated Rayleigh scattering when the frequencies of the two waves differ by the inverse of the excited-state lifetime. The energy transfer between two nearly equal energy pulses from an alexandrite laser tuned near the 42S 1/2 →42P 3/2 transition of potassium vapor was measured. It was found that as much as 85% of the total incident energy was contained in one of the output beams 相似文献
12.
Hongyuan Shen Tianguan Lian Ruirong Zheng Yuping Zhou Guijang Yu Chenghui Huang Hong Liao Zhengdong Zheng 《Quantum Electronics, IEEE Journal of》1989,25(2):144-146
A method for the simultaneous measurement of the stimulated emission cross section and fluorescence lifetime by studying the relation between laser parameters and the laser relaxation oscillation frequency is discussed. The stimulated emission cross section for the 4F 3/2-4I 13/2 transition of Nd3+ ion in YAP crystal was measured to be (22±1)×10-20 cm2 相似文献
13.
Schmiedberger J. Kodymova J. Kovar J. Spalek O. Trenda P. 《Quantum Electronics, IEEE Journal of》1991,27(6):1262-1264
A magnetic modulation of gain in a continuous-wave (CW) chemical oxygen-iodine laser (COIL) is proposed for several regimes of laser generation. The principle of the method proposed is based on a direct magnetic modulation of gain in the active zone of a COIL utilizing the Zeeman effect on the laser transition 2P 1/2 -2P 3/2 of iodine atoms. The possible applications of this technique to control the laser generation in COIL for technological purposes are outlined 相似文献
14.
Laser operation was achieved in a Cr-doped crystal of La3 Ga5SiO14. The laser had a free-running wavelength of 960 nm at room temperature from 862 to 1107 nm. Up to 80 mW output power has been measured with 1.5 W of pump power absorbed from a krypton ion laser. The 4T 2 fluorescence spectrum showed a peak at 890 nm indicating an unusually large Franck-Condon shift. At room temperature the fluorescence lifetime was 5.3 μs and the fluorescence quantum yield was measured to be about 14% 相似文献
15.
Barnes W.L. Laming R.I. Tarbox E.J. Morkel P.R. 《Quantum Electronics, IEEE Journal of》1991,27(4):1004-1010
A detailed set of measurements is presented on determining the emission and absorption cross sections of Er3+ doped fibers for the 4I 13/2→4I 15/2 transition. Two techniques are employed: the Fuchtbauer-Ladenberg analysis, based on spectroscopic data, and a more direct technique involving optical saturation of the transition. The cross sections, and in particular their ratio, are significantly different for the two techniques. Possible reasons for this are discussed, and it is concluded that the Fuchtbauer-Ladenberg approach is inappropriate in this situation 相似文献
16.
A new organic electrooptic crystal, 2,6-dibromo-N-methyl-4-nitroaniline, is reported. The crystal structure was determined by X-ray diffraction (orthorhombic, space group Fdd2, point group mm2, Z =16, a =11.745 Å, b =29.640 Å, c =10.807 Å). The refractive indexes were measured at several wavelengths between 500 and 1100 nm (at 632.8 nm, n a=1.90, n b=1.62, and n c=1.48) and fit the data to a single oscillator Sellmeier equation. A report is presented on measurements of the linear electrooptic effect, yielding the combined coefficients n a 3r 13-n c3 r 33, as well as the first known measurements of the quadratic electrooptic effect in an organic crystal, yielding the coefficients r 42 and r 51 at 514.5, 632.8, and 810 nm. Good agreement is found between the observed dispersion in the electrooptic coefficients and that predicted by the simple two-level dispersion model 相似文献
17.
Connectivity properties of a packet radio network model 总被引:16,自引:0,他引:16
Philips T.K. Panwar S.S. Tantawi A.N. 《IEEE transactions on information theory / Professional Technical Group on Information Theory》1989,35(5):1044-1047
A model of a packet radio network in which transmitters with range R are distributed according to a two-dimensional Poisson point process with density D is examined. To ensure network connectivity, it is shown that πR 2D , the expected number of nearest neighbors of a transmitter, must grow logarithmically with the area of the network. For an infinite area there exists an infinite connected component with nonzero probability if π R 2D >N 0, for some critical value N 0. It is shown that 2.195<N 0<10.526 相似文献
18.
The frequency of an InGaAsP distributed-feedback (DFB) laser was locked to the 2p 10-3d 5 transition of argon atoms at 1.2960 μm using the optogalvanic signal obtained from a commercial miniature glow lamp. At a discharge current of 500 μA, the signal-to-noise ratio of the optogalvanic signal corresponding to the Ar transition was about 18 dB. The peak-to-peak width of the first derivative signal was 650 MHz. The slope of the signal was 0.32 μV/MHz near the center of the transition. By using the linear portion of the first-derivative signal, the laser frequency was locked to the Ar 2p 10-3d 5 transition. The peak-to-peak frequency fluctuations in the free-running condition were estimated to be 650 MHz, which is mainly due to laser temperature fluctuations. When the servo-loop was closed, the frequency stability was improved to better than 13 MHz 相似文献
19.
The OMDR (optical-microwave double resonance) spectrum of 87 Rb with the aim of using a frequency-stabilized GaAs semiconductor laser instead of an Rb lamp as a pumping source in a gas-cell-type Rb frequency standard. Natural isotope 87Rb was sealed in a glass cell with buffer gases (Ar/N 2=1.2, total pressure=39 torr). The double resonance signal in the 5P 1/2(F =2)←5S 1/2( F =1) transition appearing at the resonance to the F =2←1 hyperfine transition of the 5S 1/2 state was detected. The optimum operational cell temperature was 56°C. The peak-to-peak frequency width of the atomic hyperfine resonance discriminator used to stabilize the microwave frequency shifts induced by detuning of the laser frequency, changes in the laser and microwave powers, and temperature drift of the cell were investigated 相似文献
20.
Local fractional population measurement of the upper state 4I 13/2 of an erbium-doped fiber amplifier
A method of measuring the local fractional population of the upper state 4I 13/2 of an erbium-doped amplifier is investigated. The local fractional population is related theoretically by EDF parameters to the local spontaneous emission (SE) power that leaks laterally from the EDF. The proportional constant between the fractional population and the detected SE power is determined experimentally by measuring saturated spontaneous emission power. The local fractional population of a 19.7 m-long EDF, pumped with a 1.48 μm light and injected with a 1.552 μm signal light, was measured by detecting the local SE power with a Ge photodiode having a diameter of 2 mm. The measured fractional population coincides with the calculated value 相似文献