共查询到20条相似文献,搜索用时 31 毫秒
1.
A stable laser with F3+ and F2 mixed color centers in LiF crystal is constructed using a transversely pumped cavity at room temperature. The mixed color
center laser is pumped with a nitrogen-laser-pumped dye laser. A pulse output of the laser is 0.23 mJ. The pulse widths of
the F3+ and F2 color center lasers are about 12 and 8.5 ns, respectively. The optical–optical conversion efficiency is about 5.0%. The divergence
of the F3+ color center laser beam is about 2.2 mrad and that of the F2 color center laser beam about 3.5 mrad. The polarization of the mixed color center laser is about 0.97. The output of the
F3+ color center laser extends from 515 to 575 nm and peaks at 540 nm, while that of the F2 color center laser extends from 633 to 705 nm and peaks at 667 nm. 相似文献
2.
Jesús?álvarez-Ruiz Marien?López-Arias Rebeca?de?Nalda Margarita?Martín Andrés?Arregui Luis?Ba?ares 《Applied Physics A: Materials Science & Processing》2009,95(3):681-687
The formation of cationic clusters in the laser ablation of CdS targets has been investigated as a function of wavelength
and fluence by mass spectrometric analysis of the plume. Ablation was carried out at the laser wavelengths of 1064, 532, 355,
and 266 nm in order to scan the interaction regimes below and above the energy band gap of the material. In all cases, the
mass spectra showed stoichiometric Cd
n
S
n
+ and nonstoichiometric Cd
n
S
n−1+, Cd
n
S
n+1+, and Cd
n
S
n+2+ clusters up to 4900 amu. Cluster size distributions were well represented by a log-normal function, although larger relative
abundance for clusters with n=13, 16, 19, 34 was observed (magic numbers). The laser threshold fluence for cluster observation was strongly dependent on
wavelength, ranging from around 16 mJ/cm2 at 266 nm to more than 300 mJ/cm2 at 532 and 1064 nm. According to the behavior of the detected species as a function of fluence, two distinct families were
identified: the “light” family containing S2+ and Cd+ and the “heavy” clusterized family grouping Cd2+ and Cd
n
S
m
+. In terms of fluence, it has been determined that the best ratio for clusterization is achieved close to the threshold of
appearance of clusters at all wavelengths. At 1064, 532, and 355 nm, the production of “heavy” cations as a function of fluence
showed a maximum, indicating the participation of competitive effects, whereas saturation is observed at 266 nm. In terms
of relative production, the contribution of the “heavy” family to the total cation signal was significantly lower for 266 nm
than for the longer wavelengths. Irradiation at 355 nm in the fluence region of 200 mJ/cm2 has been identified as the optimum for the generation of large clusters in CdS. 相似文献
3.
A Hanle signal is observed in the absorption of a cell filled with nitrogen dioxide NO2 at room temperature. The excitation was performed by an Ar+ laser at a wavelength of 476.4 nm. 相似文献
4.
O. Kreitschitz W. Husinsky G. Betz N. H. Tolk 《Applied Physics A: Materials Science & Processing》1994,58(6):563-571
The intensity dependence of the total and specific yields of positive ions desorbed from SrF2 under 193 nm and 308 nm excimer-laser irradiation has been investigated by the time-of-flight method. The following positive ion species have been detected: F+, Sr+, Sr++, SrF++ and SrF
2
+
. The Sr+ and SrF+ emission yields are found to increase as E
n, where E represents the laser energy per pulse. The exponent n is related to defect-initiated neutral particle emission and gas-phase ionization. The influence of surface damage on this power dependence is investigated. The F+ emission yield showed a quite different behaviour compared to that of the Sr+ and SrF+ emission. At both wavelengths the total positive ion emission yields saturate at a certain laser energy. In the saturation regime the SrF+ emission vanishes and alternative emission of F+ and Sr+ was observed at both wavelengths, but the total emission yield in the saturation regime (F+ + Sr+) remained constant. A Scanning Electron Microscope (SEM) was used to investigate the damage spots after laser irradiation for thermal effects. 相似文献
5.
R. M. El-Agmy 《Laser Physics》2008,18(6):803-806
A successful continuous-wave (CW) ultraviolet (UV) laser in a Tm+3-doped ZBLAN fiber, operated at 284 nm (1 I 6 → 3 H 6 transition of Tm+3) is demonstrated. The excitation uses a four-step upconversion scheme. The pump source is a Nd:YAG laser operated at 1.064 μm. A laser output power of 42 μW continuous wave was obtained for 590 mW of the launched pump power. The slope efficiency with respect to the launched pump power was measured to be 9%. Ultraviolet (at 365 nm) and visible (at 453 and 480 nm) radiation was also observed. 相似文献
6.
The He/N2 system lasing on the N
2
+
(B)N
2
+
(X, 0) transition at 391 nm and on the N
2
+
(B)N
2
+
(X, 1) transition at 428 nm was investigated by e-beam excitation. By adding H2 the lower laser state is efficiently quenched, which leads to a drastic improvement of the laser properties. A kinetic model is proposed which accounts for the experimental results. For a laser amplifier operated at 5 bar total efficiencies of 0.6% and 0.7% are predicted for the 391 nm and the 428 nm transitions respectively. 相似文献
7.
8.
Continuous laser oscillation was observed for various B 3Π0+u → X 1Σ0+g transitions of molecular iodine in the wavelength range of 583.0 nm to 1338 nm excited by a single frequency 514.5 nm argon laser. For pump powers of 3W output powers up to 250 mW were obtained. Some properties of the laser system are discussed. 相似文献
9.
The photopolymerization of C60 and Li@C60 films was investigated by means of optical second-harmonic generation. The films were deposited under ultra-high-vacuum conditions and irradiated in situ with an Ar+ laser at 514 nm. The second harmonic generated by a Nd:YAG laser working at 1064 nm was monitored after different steps of irradiation. Photopolymerization was observed after very low irradiation doses, of the order of 1020 photons/cm2, and confirmed with infrared absorption spectroscopy. Similar kinetics for C60 and Li@C60 were observed. The measurements give evidence for photopolymerization of the endohedral fullerene Li@C60. PACS 78.30.Na; 82.50.Hp; 81.05.Tp 相似文献
10.
A. Brockhinke A.T. Hartlieb K. Kohse-Höinghaus D.R. Crosley 《Applied physics. B, Lasers and optics》1998,67(5):659-665
2 in a flame, excited by a tunable KrF laser near 248 nm. The first comprises several P and R lines of the (1,0) band of the
e 3Πg-a 3Πu Fox–Herzberg system, with fluorescence bands extending past 350 nm. The second is the band head region of the (7,1) band
of the D 1Σu
+←B′ 1Σg
+ system, with fluorescence at 232 nm from D to the X 1Σg
+ ground state. Neither band has been previously observed in any environment. The flame in these experiments is highly sooting,
and the C2 seen here is likely produced by laser vaporization of the soot with subsequent laser photolysis of a C2 precursor. In a rich flame, this fluorescence could cause interferences in other studies such as KrF laser Raman scattering.
Moreover, signal level calculations suggest native C2 near 10 ppm could be readily observed using the Fox–Herzberg excitation. Raman measurements of major species (X≥0.01) in
the same flame, using the KrF laser, are in good agreement with a model prediction.
Received: 2 April 1998/Revised version: 8 June 1998 相似文献
11.
F. Kokai Y. Koga Y. Kakudate M. Kawaguchi S. Fujiwara M. Kubota K. Fukuda 《Applied Physics A: Materials Science & Processing》1994,59(3):299-304
Laser-ionization Time-Of-Flight (TOF) mass-spectrometric studies have been carried out on the 532 nm and 1064 nm laser ablation products from a nitrogen-rich polymer. The polymer used had an elemental composition of C6.0N8.9H3.4 and consisted of C=N, C-N, and N-H chemical bonds. The TOF mass spectra observed were composed of various peaks (150 amu) depending on the ablation laser wavelength. The primary peaks were assigned to C+, CN+, CHnN+
2 (n=1–3) and C2H2N+
3 for 532 nm ablation, and C+, C+
3, HCN+, HCCN+, CH2NH+, HNCN+, H3NCN+, and C4H4N+
7 for 1064 nm ablation. The flight velocity distributions with peak velocities ranging from 8.6×103 cm/s to 3.8×104 cm/s were measured for these products. The distinct velocity distributions observed between small and large products indicate the presence of two origins in the fragment ejection process from the polymer for both 532 nm and 1064 nm ablation. Furthermore, we suggest an importance of the translational energy of the fragments for the product generation in the laser plume. 相似文献
12.
A novel technique based on the excimer laser induced crystallization and modification of TiO2 thin films is being reported. W+6 ions loaded TiO2 (WTO) precursor films were prepared by a modified sol–gel method and spin-coated onto microscopic glass slides. Pulsed KrF
(248 nm, 13 ns) excimer laser was used to irradiate the WTO amorphous films at various laser parameters. Mesoporous and nanostructured
films consisting of anatase and rutile were obtained after laser irradiation at room temperature. The effect of varying W+6 ions concentrations on structural and optical properties the WTO films was analyzed by X-ray diffraction, field-emission
scanning electron microscope, UV-Vis spectrophotometer and transmission electron microscope before and after laser treatment.
Films irradiated for 10 pulses at 65–75 mJ/cm2 laser fluence, exhibited anatase whereas higher parameters promoted the formation of rutile. XPS results revealed WO3 along with minor proportion of WO2 compounds after laser irradiation. Photo-absorbance of the WTO films was increased with increase in W+6 ions concentration in the film. TEM results exhibited a crystallite size of 15 nm which was confirmed from SEM results as
well. 相似文献
13.
14.
15.
P. Mogyorósi K. Piglmayer R. Kullmer D. Bäuerle 《Applied Physics A: Materials Science & Processing》1988,45(4):293-299
Laser-induced chemical etching of single-crystalline (100) Si in Cl2 atmosphere has been investigated for continuous Ar+ and Kr+ laser irradiation at around 351 nm, and at 457.9, 488.0, 514.5, and 647.1 nm. For laser irradiances below 105 W/cm2 the etching mechanism is non-thermal, and is based on photo-generated electron-hole pairs within the Si surface and Cl atoms produced within the gas phase. The experimental results are compared with model calculations. 相似文献
16.
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
17.
通过在稳定连续波运转的Yb:YAG 激光器中插入不同掺杂浓度的新型钠、镱共掺的氟化钙晶体的对比性实验,证明了镱、钠共掺的氟化钙晶体在1050nm具有明显的可饱和吸收作用,从而解释了该晶体作为增益介质在该波段总是趋于自调Q运转的原因.Yb3+离子是该晶体可饱和吸收作用的主要因素,但是共掺入适当的Na离子可以明显改善晶体的调Q效果.优化共掺镱、钠离子的浓度和比例后的氟化钙晶体能够作为1050nm波段激光器的被动Q开关.
关键词:
镱、钠共掺氟化钙
可饱和吸收体
调Q 相似文献
18.
F. Kokai Y. Kakudate H. Togashi Y. Koga S. Fujiwara 《Applied Physics A: Materials Science & Processing》1995,60(1):31-34
Laser-ionization time-of-flight mass spectrometry has been used to probe laser-ablation products from a nitrogen-rich polymer at a wavelength of 308 nm. The ablation products at a laser fluence of 150 mJ/cm2 showed, similar to 532 nm ablation studied previously [18], two strong peaks due to neutral species that were assigned to C+ and CN+, as well as several weak peaks that were assigned to CH+, HCN+, HCNH+, HnN–CN+ (n=1–3), and H2N–C=N–CN+ or H2N–C=N–CN+. The ablation products at 870 mJ/cm2 revealed, in addition to a broad signal due to ionic products generated directly by the ablation laser, several peaks due to neutral products that were assigned to C+, C
2
+
, C
3
+
, CN+, HCN+, HCNH+, and NCCN+. The most probable flight velocities for major neutral products are 5.7×104 cm/s at 150 mJ/cm2 and 2.3–2.7×104 cm/s at 870 mJ/cm2. The results at a laser fluence of 150 mJ/cm2 support the finding that the translational energy of the tragments has importance for the collision-induced product generation in the laser plume, as suggested earlier [18]. Furthermore, the product generation at 870 mJ/cm2 is interpreted by the ejection of small neutral and ionic fragments, and subsequent reactions among the fragments. 相似文献
19.
F. Spieweck 《Applied Physics A: Materials Science & Processing》1974,3(5):429-430
Wavelength stabilization of the green Ar+ laser line at 514.5 nm by129I2 absorption was found to be more favourable than by127I2 absorption because the maximum of129I2 absorption is closer to the center of the 514.5 nm gain curve. A simple method for stabilizing a short air cooled laser with
only one servo loop is given, yielding a stability of 10−8 λ. 相似文献