共查询到20条相似文献,搜索用时 31 毫秒
1.
M. Stanislawki J. Meister T. Mitra M.M. Ivanenko K. Zanger P. Hering 《Applied physics. B, Lasers and optics》2001,72(1):115-120
The Er:YAG and the CO2 laser are competitors in the field of hard tissue ablation. The use of Er:YAG lasers (2.94 μm, pulse length
L of 100 to 200 μs) show smaller areas of thermal defects then ‘‘superpulsed’’ CO2 lasers with pulse lengths of approximately 100 μs. Only the development of a Q-switched CO2 laser (9.6 μm, τL=250 ns) allowed for similar results. In this paper new results for the Er:YAG and the Q-switched CO2 laser under the influence of water spray will be presented. Several parameters are of special interest for these investigations:
the specific ablation energy, which shows a minimum for the CO2 laser at an energy density of 9 J/cm 2 and a broad shallow minimum in the range of 10 to 70 J/cm2 for the Er:YAG laser, and comparison of the cut-shape and depth. Surface effects and cutting velocity are discussed based
on SEM pictures.
Received: 19 July 2000 / Revised version: 1 November 2000 / Published online: 30 November 2000 相似文献
2.
S. Gloor V. Romano W. Lüthy H.P. Weber V.V. Kononenko S.M. Pimenov V.I. Konov A.V. Khomich 《Applied Physics A: Materials Science & Processing》2000,70(5):547-550
Two-dimensional antireflective periodical microstructures for the IR range are fabricated on the surface of CVD diamond films.
These structures are created using an ArF excimer laser (λ=193 nm) and a direct writing scheme consisting of a beam collimator
and a microscope objective to focus the beam onto the sample. Two different arrays are investigated. One has a spacing of
3 μm and is produced with single shots and the other one has a spacing of 4 μm and is produced with three shots per spot.
The hole depth and shape are measured with an atomic force microscope (AFM). The optical transmittance and the scattering
properties of the structure at 10.6 μm are reported for a CO2 laser beam. With a spectrometer further transmission measurements in the range of 5 to 20 μm are performed.
Received: 16 September 1999 / Accepted: 11 October 1999 / Published online: 24 March 2000 相似文献
3.
W. Que Y. Zhou Y.L. Lam Y.C. Chan C.H. Kam 《Applied Physics A: Materials Science & Processing》2001,73(2):171-176
SiO2/TiO2/γ-glycidoxypropyltrimethoxysilane composite materials processed by the sol-gel technique were studied for optical waveguide
applications. Waveguide films with thickness more than 1.7 μm were prepared on a silicon substrate by a single-coating process
and low-temperature heat treatment from these high-titanium-content composite materials. Scanning electron microscopy (SEM),
atomic force microscopy (AFM), thermal gravimetric analysis (TGA), UV-visible spectroscopy (UV-VIS), Fourier-transform infrared
spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS) have been used to characterize the waveguide films. TGA curves
showed that organic compounds in the composite materials would decompose in the temperature range from 200 °C to 480 °C. SEM,
AFM and UV-VIS results showed that a dense, porous-free, and high transparency in the visible range waveguide film could be
obtained at a low heat-treatment temperature. It was also noted that the carbon content in the film with higher titanium content
heated at high temperature was evidenced by XPS. The waveguide propagation loss properties of the composite material films
were also investigated and showed a dependence on the titanium molar fraction.
Received: 13 June 2000 / Accepted: 21 June 2000 / Published online: 20 September 2000 相似文献
4.
We demonstrate a novel traveling-wave type optical parametric generator based on 1.25 μm pumping of AgGaS2 that produces tunable, high-power and almost transform-limited 200-fs pulses in the mid-infrared up to 8 μm.
Received: 24 January 2000 / Revised version: 1 March 2000 / Published online: 5 April 2000 相似文献
5.
The influence of an external field on photorefractive recording in Sn2P2S6 (SPS) crystals is studied. A large gain factor of more then 15 cm-1 is achieved for a grating spacing of 12 μm at λ=0.9 μm. For an applied field exceeding ±200 V/cm a switching of the beam
coupling direction is detected, exhibiting a pronounced hysteresis.
Received: 25 October 2000 / Revised version: 18 January 2001 / Published online: 21 March 2001 相似文献
6.
D. Mazzotti P. De Natale G. Giusfredi C. Fort J.A. Mitchell L.W. Hollberg 《Applied physics. B, Lasers and optics》2000,70(6):747-750
We report difference-frequency generation (DFG) in periodically poled lithium niobate (PPLN) around 4.25 μm using a cw Nd:YAG
and an injection-locked diode laser. This system provides a narrow linewidth source at 4.25 μm with near-shot-noise-limited
operation. A conversion efficiency close to the theoretical limit is obtained. Detection of CO2 absorption spectra is demonstrated and further improvements and applications to high sensitivity spectroscopy are discussed.
Received: 12 August 1999 / Revised version: 21 January 2000 / Published online: 24 March 2000 相似文献
7.
K. Fradkin-Kashi A. Arie P. Urenski G. Rosenman 《Applied physics. B, Lasers and optics》2000,71(2):251-255
Tunable mid-infrared coherent radiation (3.25-
3.7 μm) is generated by quasi-phase-matched difference frequency generation in a multi-grating periodically-poled RbTiOAsO4 crystal. The spontaneous polarization and coercive field of flux-grown RbTiOAsO4 are determined by polarization switching measurements. The nonlinear interaction enables us to explore the optical and nonlinear
properties of this material in the mid-infrared range, where data is scarce. The measurements are used to derive a mid- infrared
corrected dispersion equation for nz in RbTiOAsO4. This equation is in excellent agreement with previously published measurements of nonlinear interactions in periodically-poled
RbTiOAsO4. The measured wavelength and temperature bandwidths are ≈48 nm cm and ≈29 °C cm, respectively. A relatively high temperature
tuning slope of the phase-matched idler wavelength, -1.27 nm/°C, is measured. This may be useful for realizing temperature-tuned
nonlinear devices.
Received: 30 March 2000 / Revised version: 9 May 2000 / Published online: 30 June 2000 相似文献
8.
I. Sokólska E. Heumann S. Kück T. Lukasiewicz 《Applied physics. B, Lasers and optics》2000,71(6):893-896
Laser oscillation around 1.6 μm was realised at room temperature for low-doped Er:YVO4 crystals (0.5 at % and 1 at %) as well as for Er(1 at %), Yb(5 at %):YVO4 crystal in continuous-wave mode. The maximum slope of the input–output curve was about 19% (vs. absorbed power) for Er(0.5 at %):YVO4. The laser oscillation was discretely tunable in the spectral range between 1531 and 1604 nm.
Received: 24. August 2000 / Published online: 8 November 2000 相似文献
9.
High-power picosecond LiB3O5 optical parametric oscillators tunable in the blue spectral range 总被引:2,自引:0,他引:2
The paper reports on an experimental investigation and numerical analysis of noncritically and critically phasematched LiB3O5 (LBO) optical parametric oscillators (OPOs) synchronously pumped by the third harmonic of a cw diode-pumped mode-locked Nd:YVO4 oscillator–amplifier system. The laser system generates 9.0 W of 355-nm mode-locked radiation with a pulse duration of 7.5 ps
and a repetition rate of 84 MHz. The LBO OPO, synchronously pumped by the 355-nm pulses, generates a signal wave tunable in
the blue spectral range 457–479 nm. With a power of up to 5.0 W at 462 nm and 1.7 W at 1535 nm the conversion efficiency is
74%. The OPO is characterized experimentally by measuring the output power (and its dependence on the pump power, the transmission
of the output coupler and the resonator length) and the pulse properties (such as pulse duration and spectral width). Also
the beam quality of the resonant and nonresonant waves is investigated. The measured results are compared with the predictions
of a numerical analysis for Gaussian laser and OPO beams. In addition to the blue-signal output visible-red 629-nm radiation
is generated by sum-frequency mixing of the 1.535-μm infrared idler wave with the residual 1.064-μm laser radiation. A power
of 1.25 W of 1.535-μm idler radiation and 5.7 W of 1.064-μm laser light generated a red 629-nm output power of 2.25 W.
Received: 2 February 2000 / Revised version: 28 July 2000 / Published online: 22 November 2000 相似文献
10.
J. Lu M. Prabhu J. Song C. Li J. Xu K. Ueda A.A. Kaminskii H. Yagi T. Yanagitani 《Applied physics. B, Lasers and optics》2000,71(4):469-473
Optical absorption, emission spectra have been measured for polycrystalline Nd-doped Y3Al5O12 ceramics. Fluorescence lifetimes of 257.6 μs, 237.6 μs, 184.2 μs and 95.6 μs have been obtained for 0.6%, 1%, 2% and 4% neodymium-doped
YAG ceramics, respectively. For the first time, highly efficient laser oscillation at 1064 nm has been obtained with this
kind of ceramics. Slope efficiency of 53% has been achieved on a uncoated 4.8-mm thick 1% Nd:YAG ceramics sample. Optical
to optical conversion efficiency is 47.6%. Laser oscillation has also been obtained with a 2% Nd:YAG ceramics. The optical
properties and laser output results have been compared with that of Nd:YAG single crystal grown by the Czochralski method.
Almost identical results have been achieved including laser experiments results. But fabrication of Nd:YAG ceramics is much
easier compared to the single-crystal growth method. And also large size (now of about 400 mm diameter×5 mm is available)
and high-concentration (>1%) Nd:YAG ceramics can be fabricated. The results show that this kind of Nd:YAG ceramics is a very
good alternative to Nd:YAG single crystal.
Received: 20 April 2000 / Published online: 16 August 2000 相似文献
11.
H. Heidrich R. Kaiser P. Albrecht S. Fidorra M. Hamacher W. Rehbein 《Applied physics. B, Lasers and optics》2001,73(5-6):581-583
Optical crosstalk from a 1.3 μm laser to a 1.55 μm photodiode on a single InP substrate, and its suppression within 1.3 μm/1.5 μm
Y-junction transceiver OEICs, has been analyzed experimentally. The results indicate that the optical crosstalk suppression
is limited by the accumulated light in the OEIC substrate coming mainly from the spontaneous emission of the integrated laser
and from stray light at the laser–waveguide butt joint interface. For OEICs, integrating lasers and photodetectors, the achievable
optical intra-chip crosstalk at present will be in the range of 30–40 dB at the required small die dimensions.
Received: 16 May 2001 / / Published online: 23 October 2001 相似文献
12.
F. Machalett K. Edinger J. Melngailis M. Diegel K. Steenbeck E. Steinbeiss 《Applied Physics A: Materials Science & Processing》2000,71(3):331-335
For direct writing of electrically conducting connections and areas into insulating gold oxide thin films a scanning Ar+ laser beam and a 30 keV Ga+ focused ion beam (FIB) have been used. The gold oxide films are prepared by magnetron sputtering under argon/oxygen plasma.
The patterning of larger areas (dimension 10–100 μm) has been carried out with the laser beam by local heating of the selected
area above the decomposition temperature of AuOx (130–150 °C). For smaller dimensions (100 nm to 10 μm) the FIB irradiation could be used. With both complementary methods
a reduction of the sheet resistance by 6–7 orders of magnitude has been achieved in the irradiated regions (e.g. with FIB
irradiation from 1.5×107 Ω/□ to approximately 6 Ω/□). The energy-dispersive X-ray analysis (EDX) show a considerably reduced oxygen content in the
irradiated areas, and scanning electron microscopy (SEM), as well as atomic force microscopy (AFM) investigations, indicate
that the FIB patterning in the low-dose region (1014 Ga+/cm2) is combined with a volume reduction, which is caused by oxygen escape rather than by sputtering.
Received: 30 May 2000 / Accepted: 31 May 2000 / Published online: 13 July 2000 相似文献
13.
A 50 cm silver coated hollow fiber with inner diameter of 250 μm and filled with argon has been used to compress optical pulses
from a Ti:sapphire laser at 800 nm. Input pulses with energy of 250 μJ and duration of 110 fs were used and compressed pulses
with energy of 220 μJ and duration of 20 fs were generated by using a prism compressor. Numerical and experimental results
are compared. There is good agreement between the measured beam diameters of the hollow-fiber output pulse and the calculated
values obtained from propagation of the HE11 mode into free space. For comparison, a similar uncoated fused-silica hollow fiber was also used to obtain 20 fs compressed
pulses with an energy of 190 μJ.
Received: 7 September 2002 / Published online: 26 March 2003
RID="*"
ID="*"Corresponding author. Fax: +1-780/492-1811, E-mail: mohebbi@ee.ualberta.ca 相似文献
14.
G.M. Gibson G.A. Turnbull M. Ebrahimzadeh M.H. Dunn H. Karlsson G. Arvidsson F. Laurell 《Applied physics. B, Lasers and optics》1998,67(5):675-677
4 (PPKTP). We generated 12 μW of radiation tunable around 1.6 μm by difference-frequency mixing of the outputs of a frequency-doubled
Nd:YLF laser at 523 nm (240 mW) and a tunable Ti:sapphire laser near 760 nm (340 mW). A temperature tuning rate of 0.73 nm/°C
for the generated wavelength and a FWHM temperature acceptance bandwidth of 6.9 °C cm was observed. The effective d33 coefficient was estimated to be ∼5 pm/V.
Received: 02 September 1998 相似文献
15.
We present the first photoacoustic spectrometer for gas sensing employing both the fundamental and the frequency-doubled radiation
of a continuously tunable high-pressure CO2 laser with room temperature operation. A quasi-phase-matched diffusion-bonded GaAs crystal is used in the system for second-harmonic
generation. A pulsed photoacoustic detection scheme with a non-resonant cell, equipped with an 80-microphone array, is employed.
The wide continuous tuning range in the fundamental (9.2–10.7 μm) and the frequency-doubled (4.6–5.35 μm) regimes, together
with the narrow linewidth of 540 MHz (0.018 cm-1) for the 10-μm region and of 1050 MHz (0.0315 cm-1) for the 5-μm region, allow the measurement of gas mixtures, individual species and isotope discrimination. This is illustrated
with measurements on NO and CO2. The measured isotope ratio 15
NO/14
NO=(3.58±0.55)×10-3 agrees well with the literature (3.700×10-3) and demonstrates the good selectivity of the system.
Received: 30 April 2002 / Revised version: 10 June 2002 / Published online: 2 September 2002
RID="*"
ID="*"Corresponding author. Fax: +41-1/633-1077, E-mail: sigrist@iqe.phys.ethz.ch 相似文献
16.
Scanning electron microscopy (SEM), Fourier transform infrared (FTIR) transmission, and Hall effect measurements were performed to investigate the structural, optical, and electrical properties of as-grown and in situ-annealed Hg0.7Cd0.3Te epilayers grown on CdTe buffer layers by using molecular beam epitaxy. After the Hg0.7Cd0.3Te epilayers had been annealed in a Hg-cell flux atmosphere, the SEM images showed that the surface morphologies of the Hg0.7Cd0.3Te thin films were mirror-like with no indication of pinholes or defects, and the FTIR spectra showed that the transmission intensities had increased in comparison to that of the as-grown Hg0.7Cd0.3Te epilayer. Hall-effect measurements showed that n-Hg0.7Cd0.3Te epilayers were converted to p-Hg0.7Cd0.3Te epilayers. These results indicate that the surface, optical, and electrical properties of the Hg1 − xCdxTe epilayers are improved by annealing and that as-grown n-Hg1 − xCdxTe epilayers can be converted to p-Hg1 − xCdxTe epilayers by in situ annealing. 相似文献
17.
J. Liu X. Xu C.Q. Wang S. Zhang J. Wang H. Chen Z. Shao M. Jiang 《Applied physics. B, Lasers and optics》2001,72(2):163-166
The characteristics of intracavity second-harmonic generation (SHG) at 1.06 μm in GdCa4O(BO3)3 (GdCOB) crystals cut for different type I phase-matching (PM) directions of (θ,φ)=(66.8°, 132.3°); (19.4°, 0°); (90°, 46°)
have been investigated. It was found that the intracavity SHG was significantly efficient in the PM direction of (66.8°, 132.3°),
and that the intrinsic lower effective nonlinear coefficient (deff) was responsible for the less-efficient SHG in the other two directions. A maximum CW SHG output power of 2.81 W was obtained
with an optical conversion efficiency of 18.7%, while the corresponding effective intracavity SHG efficiency was determined
to be 41.3%. The intracavity SHG efficiency of GdCOB has been found to reach two-thirds of that obtained with type II phase-matching
KTiOPO4 (KTP).
Received: 26 April 2000 / Revised version: 3 July 2000 / Published online: 5 October 2000 相似文献
18.
M. Okuyama T. Usuki Y. Hamakawa T. Nakagawa 《Applied Physics A: Materials Science & Processing》1980,21(4):339-343
A series of experiments for growing epitaxial PLZT thin films has been made with rf sputtering. X-ray and electron diffraction
analyses confirm that the fabricated films grow epitaxially on SrTiO3 and MgO crystals. A good transparency in the region above 0.4 μm to infrared with good ferroelectric properties is obtained.
Propagation loss of He−Ne laser light is less than 6 dB/cm, and the PLZT thin film is a promising candidate for the optical
modulator and other functional elements for integrated optics. 相似文献
19.
T.V. Kononenko S.V. Garnov S.M. Pimenov V.I. Konov V. Romano B. Borsos H.P. Weber 《Applied Physics A: Materials Science & Processing》2000,71(6):627-631
Laser ablation of thin TiN films deposited on steel substrates has been studied under wide-range variation of irradiation
conditions (pulsewidth, wavelength, energy density and spot size). It has been demonstrated that both picosecond (150–300 ps)
and nanosecond (5–9 ns) laser pulses were suitable for controllable ablation and microstructuring of a 1-μm-thick TiN film
unlike longer 150-ns pulses. The ablation rate was found to be practically independent of the wavelength (270–1078 nm) and
pulsewidth (150 ps–9 ns), but it increased substantially when the size of a laser spot was reduced from 15–60 μm to 3 μm.
The laser ablation technique was applied to produce microstructures in the thin TiN films consisting of microcraters with
a typical size of 3–5 μm in diameter and depth less than 1 μm. Tests of lubricated sliding of the laser-structured TiN films
against a steel ball showed that the durability of lubricated sliding increased by 25% as compared to that of the original
TiN film.
Received: 28 July 1999 / Accepted: 17 April 2000 / Published online: 20 September 2000 相似文献
20.
G.S. Wang X.J. Meng Z.Q. Lai J. Yu J.L. Sun S.L. Guo J.H. Chu 《Applied Physics A: Materials Science & Processing》2003,76(1):83-86
Ferroelectric Bi3.25La0.75Ti3O12 (BLT) thin films have been grown on Pt/Ti/SiO2/Si substrates by chemical solution methods. X-ray diffraction analysis shows that BLT thin films are polycrystalline with
(171)-preferential orientation. Atomic force microscopy investigation shows that they have large grains about 120 nm in size.
A Pt/BLT/Pt capacitor has been fabricated and showed excellent ferroelectricity, with a remnant polarization and coercive
field of 24 μC/cm2 and 116 kV/cm, respectively. The capacitor shows no polarization fatigue up to 109 switching cycles. The optical constants (n,k) of the BLT thin films in the wavelength range 0.35–1.7 μm were obtained by
spectroscopic ellipsometry measurements, and the band-gap energy was found to be about 3.25 eV.
Received: 16 October 2001 / Accepted: 6 January 2002 / Published online: 3 June 2002
RID="*"
ID="*"Corresponding author. Fax: +86-21/65830-734, E-mail: gswang@mail.sitp.ac.cn 相似文献