共查询到20条相似文献,搜索用时 31 毫秒
1.
M. Fally 《Applied physics. B, Lasers and optics》2002,75(4-5):405-426
Since its discovery in 1966, the photorefractive effect, i.e. the change of the refractive index upon illumination with light,
has been studied extensively in various materials and has turned out to play a key role in modern optical technologies like
photonics. This article focuses on substances that change their refractive index for neutrons when irradiated with light.
In analogy to light optics, we call them photo-neutronrefractive. After a short introduction to the relevant concepts of neutron
optics, two materials exhibiting this effect, a photopolymer and an electrooptic crystal, are presented. Further, we discuss
the progress made concerning the development of creating light-induced gratings for neutron diffraction, which culminated
in the setup of an interferometer for cold neutrons. Experiments performed on photo-neutronrefractive materials are surveyed
and the variety of corresponding results obtained is presented, including a discussion of their impact on material science,
neutron optics, and the foundations of physics.
Received: 23 July 2002 / Published online: 25 October 2002
RID="*"
ID="*"Corresponding author. Fax: +43-1/4277-9511, E-mail: martin.fally@exp.univie.ac.at 相似文献
2.
Fabrication of planar gratings by direct ablation using an ultrashort pulse laser in a common optical path configuration 总被引:4,自引:0,他引:4
K. Venkatakrishnan N.R. Sivakumar B. Tan 《Applied Physics A: Materials Science & Processing》2003,76(2):143-146
Planar gratings have wide applications and to date, many methods for the fabrication of gratings have been reported. Ultrashort
pulse lasers have been used for the machining of gratings primarily because they allow direct ablation and the manufacturing
of sub-wavelength structures. In this paper, we present a novel direct ablation technique for the fabrication of planar gratings
which makes use of the interference of ultrashort pulses in a common optical path configuration. This technique of grating
fabrication not only simplifies the optical setup, but also immunizes the system to extraneous and inherent vibrations, thus
enabling the manufacturing of planar gratings of good edge acuity. We have successfully fabricated planar gratings on a copper
substrate.
Received: 6 November 2001 / Accepted: 4 March 2002 / Published online: 10 September 2002
RID="*"
ID="*"Corresponding author. Fax: +65/77-904-674, E-mail: mvenkata@ntu.edu.sg 相似文献
3.
S. Pagès F. Lagugné-Labarthet T. Buffeteau C. Sourisseau 《Applied physics. B, Lasers and optics》2002,75(4-5):541-548
The self-induced rotation of the azimuth of elliptically polarized light passing through birefringent azopolymer thin films
is investigated. The experiments were carried out on thin films of the amorphous p(DR1M-co-MMA) and p(DR1M) azopolymer samples
and of the p(6MAN) derivative in its glassy and liquid-crystalline phases. In fact, using various controlled input light ellipticities,
linear birefringence (LB) and/or circular birefringence (CB) measurements were performed separately and in conjunction with
polarization analyses of the transmitted pump beam. According to a general theoretical analysis based on Jones’ matrix formalism,
it is thus shown that the induced rotation angle through the films depends mainly on the ellipticity of the input light, on
the generated LB level and, to a lesser extent, on the CB photoinduced in the liquid-crystalline phase. In the latter case,
it is concluded that irradiation with circularly polarized light does induce a chiral arrangement in the polymer film, although
the photosensitive chromophores do not contain any optically active group.
Received: 22 April 2002 / Revised version: 28 May 2002 / Published online: 25 September 2002
RID="*"
ID="*"Corresponding author. Fax: +33-5/5684-8402; E-mail: csouri@morgane.lsmc.u-bordeaux.fr 相似文献
4.
L. Nedelchev L. Nikolova A. Matharu P.S. Ramanujam 《Applied physics. B, Lasers and optics》2002,75(6-7):671-676
A study of the propagation of elliptically polarized light and the resulting formation of macroscopic chiral structures in
a series of azobenzene side-chain copolyesters, in which the morphology is varied from liquid crystalline to amorphous, is
reported. Real-time measurements are presented, showing the dynamic behavior of the photoinduced rotation of the polarization
ellipse in the different samples. The relationship between the ellipticity of the recording light and the linear birefringence
induced is studied. A numerical solution that takes into account the influence of the photoinduced linear dichroism on the
light propagation through the samples is presented.
Received: 10 June 2002 / Revised version: 26 July 2002 / Published online: 15 November 2002
RID="*"
ID="*"Corresponding author. Fax: +45-4677/4588, E-mail: lian.nedelchev@risoe.dk
RID="**"
ID="**"Permanent address: Department of Chemistry and Physics, The Nottingham Trent Unversity, Clifton Lane, Nottingham NG11 8NS,
England 相似文献
5.
D. Sabourdy V. Kermène A. Desfarges-Berthelemot M. Vampouille A. Barthélémy 《Applied physics. B, Lasers and optics》2002,75(4-5):503-507
The coherent combining of two Nd:YAG lasers using a Vernier–Michelson-type cavity has been demonstrated. The spectral behaviour
and the energetic performance are reported. We firstly show that the combining efficiency is not strongly spoilt by the gain
imbalance between the two amplifying media, and secondly, that despite the interferometric nature of the cavity, the Vernier–Michelson
laser can withstand environmental perturbations without alteration in output power.
Received: 25 April 2002 / Revised version: 18 May 2002 / Published online: 25 September 2002
RID="*"
ID="*"Corresponding author. Fax: +33-5/5545-7253, E-mail: kermene@ircom.unilim.fr 相似文献
6.
G. Tsigaridas M. Fakis I. Polyzos P. Persephonis V. Giannetas 《Applied physics. B, Lasers and optics》2003,76(1):83-86
A modification to the well-known z-scan technique for measuring optical non-linearities is introduced. It is based on directly
measuring the beam radius in the far field instead of the transmittance of the irradiance through an aperture, as in the original
version. It has the advantage of being insensitive to beam pointing instability and is almost insensitive to power fluctuations.
Furthermore, the calculations required for the determination of the non-linear parameters are simplified. For demonstrating
the advantages of the modified method, beam radius and transmittance measurements were simultaneously taken in the standard
non-linear optical material CS2. Separate fittings of these measurements gave almost the same values for the non-linearities, quite similar to those in the
literature. A common fitting has been applied to both sets of measurements, enhancing the accuracy of the method.
Received: 8 July 2002 / Revised version: 18 October 2002 / Published online: 8 January 2003
RID="*"
ID="*"Corresponding author. Fax: +30-2610/997470, E-mail: gianetas@physics.upatras.gr 相似文献
7.
Calculation of the temperature and thermal expansion of a STM tip heated by a short laser pulse 总被引:1,自引:0,他引:1
A mathematical model for the calculation of the temperature field in a scanning tunneling microscope (STM) tip under laser
illumination is developed. The duration of the laser pulse is a few nanoseconds or shorter. A Gaussian distribution of the
laser light intensity in time and space is assumed. Two different mechanisms of tip heating are taken into account: 1. due
to an enhanced electric field on the tip; 2. due to heating of the side surface of the tip by the focused spot of laser light.
An average tip temperature is calculated using the heat conductivity equation. The enhanced electric field on the tip is calculated
by the method of boundary integral equations.
Received: 20 August 2002 / Revised version: 4 December 2002 / Published online: 19 March 2003
RID="*"
ID="*"Corresponding author. Fax: +49-2551/962-490, E-mail: sklein@fh-muenster.de 相似文献
8.
A detailed analysis of new effects related to extremely asymmetrical scattering (EAS) of bulk and guided weakly dissipating
electromagnetic waves in oblique periodic gratings is presented. A very important role of the previously determined critical
grating width is demonstrated for EAS in dissipative gratings. Incident and scattered wave amplitudes inside and outside the
grating are analysed as functions of dissipation coefficient, grating width, grating amplitude, etc. Strong differences in
the patterns of scattering in gratings that are narrower and wider than the critical width are demonstrated and discussed.
Deep analogies between EAS and other resonant optical effects, such as attenuated total reflection, Fabry–Pérot interferometry,
etc. are revealed and discussed. A physical interpretation of the obtained results is presented.
Received: 19 February 2002 / Revised version: 28 June 2002 / Published online: 22 November 2002
RID="*"
ID="*"Corresponding author. Fax: +61-7/3864-9079, E-mail: d.gramotnev@qut.edu.au 相似文献
9.
Photonic crystals with stop bands located in the visible region have been fabricated by crystallizing monodispersed spherical
colloids (made of polystyrene or silica) into cubic-close-packed lattices within specially designed packing cells. These crystals
were oriented with their (111) planes parallel to their solid supports, and the number of these planes could be conveniently
controlled from 13 to 127 layers by varying the thickness of packing cells. In accordance, the stop-band attenuation of these
crystals monotonically increased from 1 to 21 dB. Our transmission spectral measurements indicated that there exists a non-linear
dependence between the stop-band attenuation and the total number of (111) planes, and this dependence could be quantitatively
simulated using the dynamic light scattering model or the photonic analogy to KKR method. The colloidal crystals presented
here should find use as components in fabricating optical devices that include sensors, mirrors, filters, switches and waveguides.
Received: 17 May 2002 / Accepted: 25 July 2002 / Published online: 4 December 2002
RID="*"
ID="*"Corresponding author. Fax: +1-206/685-8665, E-mail: xia@chem.washington.edu 相似文献
10.
Sensitive absorption measurements in the near-infrared region using off-axis integrated-cavity-output spectroscopy 总被引:3,自引:0,他引:3
A novel instrument that employs a high-finesse optical cavity as an absorption cell has been developed for sensitive measurements
of gas mixing ratios using near-infrared diode lasers and absorption-spectroscopy techniques. The instrument employs an off-axis
trajectory of the laser beam through the cell to yield an effective optical path length of several kilometers without significant
unwanted effects due to cavity resonances. As a result, a minimum detectable absorption of approximately 1.4×10-5 over an effective optical path of 4.2 km was obtained in a 1.1-Hz detection bandwidth to yield a detection sensitivity of
approximately 3.1×10-11 cm-1 Hz-1/2. The instrument has been used for sensitive measurements of CO, CH4, C2H2 and NH3.
Received: 6 May 2002 / Revised version: 31 May 2002 / Published online: 2 September 2002
RID="*"
ID="*"Corresponding author. Fax: +1-650/965-7074, E-mail: d.baer@lgrinc.com 相似文献
11.
We present an experimental study of non-linear selective reflection (SR) at a quartz–Cs-vapor interface in a V-type three-level
scheme. The non-linear selective reflection at the Cs D2 resonance line (6
S
1/2F=4→6
P
3/2) is monitored with and without pumping. The sub-Doppler reflection spectrum is observed and the effect of pumping on the
signal of the selective reflection is investigated. The experimental result is in agreement with the theoretical calculation.
Received: 16 April 2002 / Revised version: 12 June 2002 / Published online: 25 September 2002
RID="*"
ID="*"Corresponding author. Fax: +86-351/701-1500, E-mail: zhaojm@sxu.edu.cn 相似文献
12.
B. Pura J. Petykiewicz M. Wierzbicki R. Cio lek Z. Wrzesiński 《Applied physics. B, Lasers and optics》2002,75(4-5):549-551
By ellipsometric measurements we have observed the polarization variations of the primary light beam, with wavelength λ1=5145 ?, interacting with the secondary light beam of controlled variable polarization, transmitted through a TGS crystal
layer. We present a theoretical explanation based on the second-order optical nonlinearity of TGS.
Received: 4 December 2001 / Revised version: 28 May 2002 / Published online: 25 October 2002
RID="*"
ID="*"Corresponding author. Fax: +48-22/660-5447, E-mail: petyk@if.pw.edu.pl 相似文献
13.
S.M. Huang M.H. Hong B. Lukiyanchuk T.C. Chong 《Applied Physics A: Materials Science & Processing》2003,77(2):293-296
Nanostructures on metal film surfaces have been written directly using a pulsed ultraviolet laser. The optical near-field
effects of the laser were investigated. Spherical silica particles (500–1000 nm in diameter) were placed on metal films. After
laser illumination with a single laser shot, nanoholes were obtained at the original position of the particles. The mechanism
for the formation of the nanostructure patterns was investigated and found to be the near-field optical resonance effect induced
by the particles on the surface. The size of the nanohole was studied as a function of laser fluence and silica particle size.
The experimental results show a good agreement with those of the relevant theoretical calculations of the near-field light
intensity distribution. The method of particle-enhanced laser irradiation allows the study of field enhancement effects as
well as its potentialapplications for nanolithography.
Received: 10 December 2002 / Accepted: 20 January 2003 / Published online: 28 May 2003
RID="*"
ID="*"Corresponding author. Fax: +65-777/1349, E-mail: HUANG_Sumei@dsi.a-star.edu.sg 相似文献
14.
T.J. Kulp S.E. Bisson R.P. Bambha T.A. Reichardt U.-B. Goers K.W. Aniolek D.A.V. Kliner B.A. Richman K.M. Armstrong R. Sommers R. Schmitt P.E. Powers O. Levi T. Pinguet M. Fejer J.P. Koplow L. Goldberg T.G. McRae 《Applied physics. B, Lasers and optics》2002,75(2-3):317-327
Quasi-phase-matched (QPM) materials allow the generation of spectroscopically useful infrared radiation in an efficient and
broadly tunable format. Here, we describe several applications of QPM-based light sources to remote and local chemical sensing.
The remote systems are gas imagers that employ a fiber-pumped continuous-wave optical parametric oscillator or a microlaser-pumped,
diode-seeded optical parametric amplifier as the illumination source. Technology described for local sensing includes a cavity
ring down spectrometer that employs a novel optical parametric generator–amplifier to achieve ≥350 cm-1 of contiguous tuning and a long-wave infrared light source based on QPM GaAs. In each case the use of QPM materials in conjunction
with effective pump sources instills simplicity and ruggedness into the sensing systems.
Received: 15 April 2002 / Revised version: 6 June 2002 / Published online: 12 September 2002
RID="*"
ID="*"Corresponding author. Fax: +1-925/294-2595, E-mail: tjkulp@sandia.gov
RID="**"
ID="**"Present address: Corning Inc., Corning, NY 14831, USA
RID="*"
ID="*"Present address: Corning Inc., Corning, NY 14831, USA
RID="**"
ID="**"Present address: Blue Leaf Networks, Sunnyvale, CA 94086, USA
RID="***"
ID="***"Present address: Sandia National Laboratories, Albuquerque, NM 87185, USA 相似文献
15.
A. Krasyuk A. Oelsner S.A. Nepijko A. Kuksov C.M. Schneider G. Schönhense 《Applied Physics A: Materials Science & Processing》2003,76(6):863-868
Owing to its parallel image acquisition, photoemission electron microscopy is well suited for real-time observation of fast
processes on surfaces. Pulsed excitation sources like synchrotron radiation or lasers, fast electric pulsers for the study
of magnetic switching, and/or time-resolved detection can be utilised. A standard approach also being used in light optical
imaging is stroboscopic illumination of a periodic (or quasi-periodic) process. Using this technique, the time dependence
of the magnetic field in a pulsed microstrip line has been imaged in real time exploiting Lorentz-type contrast. Similarly,
the corresponding field-induced changes in the magnetisation of cobalt microstructures deposited on the microstrip line have
been observed exploiting magnetic X-ray circular dichroism as a contrast mechanism. The experiment has been performed at the
UE 56/1-PGM at BESSY II (Berlin) in the single-bunch mode.
Received: 2 September 2002 / Accepted: 2 September 2002 / Published online: 5 March 2003
RID="*"
ID="*"Corresponding author. Fax: +49-6131/392-3807, E-mail: krasyuk@mail.uni-mainz.de 相似文献
16.
J. Békési S. Szatmári P. Simon G. Marowsky 《Applied physics. B, Lasers and optics》2002,75(4-5):521-524
Applying the combination of a solid-state Ti:Sa laser system and a newly developed wide-aperture, discharge-pumped KrF amplifier,
output pulses with over 9 W average power at 300 Hz have been achieved in a single output beam. The frequency-tripled seed
pulses of the Ti:Sa system – delivering approximately 10 μJ energy at 248 nm – were amplified to over 30 mJ using a 3-pass
off-axis amplification scheme. The optical set-up has been fitted to the amplifier’s parameters, and stored-energy measurements
were carried out with different parameters in order to optimize the operational conditions of the device for the highest average
power.
Received: 10 June 2002 / Published online: 25 September 2002
RID="*"
ID="*"Corresponding author. Fax: +49-551/503-599, E-mail: jbekesi@llg.gwdg.de 相似文献
17.
D. Stifter P. Burgholzer O. Höglinger E. Götzinger C.K. Hitzenberger 《Applied Physics A: Materials Science & Processing》2003,76(6):947-951
Optical coherence tomography (OCT) is a relatively new imaging technique capable of recording cross-sectional images of transparent
and turbid structures with micrometer-scale resolution. Originally developed for biomedical imaging applications, this technique
also has a great potential for non-destructive material characterisation and testing. Polarisation-sensitive (PS) OCT is a
recent extension of classical OCT that measures and images birefringence properties of a sample, which, however, has not yet
been applied to materials science. We present imaging of glass-fibre-enforced epoxy resin compounds and the detection of dry
spots, where the epoxy did not properly penetrate the glass-fibre structure. Furthermore, we demonstrate PS-OCT imaging of
the birefringence properties of different materials. The mapping of strain fields of samples under uniaxial and non-uniform
external stress and the detection of flow patterns in injection-moulded plastic parts could be demonstrated with this technique
for the first time.
Received: 21 October 2002 / Accepted: 22 November 2002 / Published online: 29 January 2003
RID="*"
ID="*"Corresponding author. Fax: +43-732/9015-5618, E-mail: david.stifter@uar.at 相似文献
18.
Ultra-sensitive mid-infrared cavity leak-out spectroscopy using a cw optical parametric oscillator 总被引:1,自引:0,他引:1
A. Popp F. Müller F. Kühnemann S. Schiller G. von Basum H. Dahnke P. Hering M. Mürtz 《Applied physics. B, Lasers and optics》2002,75(6-7):751-754
We report a portable, all-solid-state, mid-infrared spectrometer for trace-gas analysis. The light source is a continuous-wave
optical parametric oscillator based on PPLN and pumped by a Nd:YAG laser at 1064 nm. The generated single-frequency idler
output covers the wavelength region between 2.35 and 3.75 μm. With its narrow line width, this light source is suitable for
precise trace-gas analysis with very high sensitivity. Using cavity leak-out spectroscopy we achieved a minimum detectable
absorption coefficient of 1.2×10-9 /cm (integration time: 16 s), corresponding, for example, to a detection limit of 300 parts per trillion ethane. This sensitivity
and the compact design make this trace-gas analyzer a promising tool for various in situ environmental and medical applications.
Received: 19 September 2002 / Published online: 15 November 2002
RID="*"
ID="*"Corresponding author. Fax: +49-228/733-474, E-mail: frank.kuehnemann@iap.uni-bonn.de 相似文献
19.
We have developed a tunable intense narrow-band 285 nm light source based on frequency doubling of 570 nm light in BBO. At
input powers of 840 mW (including 130 mW used for locking purposes) we generate 99 mW UV radiation with an intensity profile
suitable for laser-cooling experiments. The light is used for laser cooling of neutral magnesium atoms in a magneto-optical
trap (MOT). We capture about 5×106 atoms directly from a thermal beam and find that the major loss mechanism of the magnesium MOT is a near-resonant two-photon
ionization process.
Received: 15 February 2002 / Revised version: 13 August 2002 / Published online: 11 December 2002
RID="*"
ID="*"Corresponding author. Fax: +45-4588/7762, E-mail: dnm@mic.dtu.dk Present address: Mikroelektronik Centret, Technical
University of Denmark, Orsteds Plads, Bldg. 345 East, 2800 Kgs. Lyngby, Denmark 相似文献
20.
T. Brixner 《Applied physics. B, Lasers and optics》2003,76(5):531-540
The usage of Poincaré phase space for the representation of polarization-shaped femtosecond laser pulses is discussed. In
these types of light fields the polarization state (i.e. ellipticity and orientation) changes as a function of time within
a single laser pulse. Such deliberate variation can be achieved by frequency-domain femtosecond pulse shaping in which two
polarization components are manipulated individually. Here it is shown how these light pulses can be represented as temporal
trajectories through the ellipticity-orientation (Poincaré) phase space, whereas conventional light (either continuous-wave
or pulsed) is determined by only one specific Poincaré location. General properties of parametric Poincaré trajectories are
discussed, and their relation to experimentally accessible pulse-manipulation parameters (i.e. amplitudes and phases) determined.
Specifically, it is shown how the maximum rate by which a given polarization state can be turned into a different one (at
significant intensity levels) is limited by the spectral laser bandwidth. Apart from their direct usage in polarization-shaped
pulse representation, Poincaré trajectories also form the basis for intuitive quasi-three-dimensional renderings of the electric
field profile. There, the temporal evolution of polarization, intensity, and chirp is directly apparent in a single illustration.
Received: 10 December 2002 / Published online: 24 April 2003
RID="*"
ID="*"Corresponding author. Fax: +49-931/888-4906, E-mail: brixner@physik.uni-wuerzburg.de 相似文献