Life-cycle hypothesis: Difference between revisions

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{{redirect|Fresnel mirror|the optical mirror technology which is analogous to a [[Fresnel lens]]|Fresnel reflector}}
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In atomic physics, a '''ridged mirror''' (or '''ridged atomic mirror''', or '''Fresnel diffraction mirror''') is a kind of [[atomic mirror]], designed for the specular reflection of neutral particles ([[atoms]]) coming at the [[grazing]] incidence angle, characterised in the following:  ''in order to reduce the mean attraction of particles to the surface and increase the reflectivity, this surface has narrow ridges''.
<ref name="o1">{{cite journal
| author= F.Shimizu
| coauthors=J. Fujita
| year=2002
| title=Giant Quantum Reflection of Neon Atoms from a Ridged Silicon Surface
| journal=[[Journal of the Physical Society of Japan]]
| volume=71 | pages=5–8
| doi=10.1143/JPSJ.71.5
|arxiv = physics/0111115 |bibcode = 2002JPSJ...71....5S }}</ref>
 
==Reflectivity of ridged atomic mirrors==
[[Image:Image-Ridged Mirror figureB.png|400px|right]]
Various estimates for the efficiency of [[quantum reflection]] of waves from '''ridged mirror''' were discussed in the literature. All the estimates explicitly use the [[de Broglie wave|de Broglie theory]] about wave properties of reflected atoms.
 
===Scaling of the van der Waals force===
The ridges enhance the [[quantum reflection]] from the surface, reducing the effective constant <math>~C~</math> of the [[van der Waals force|van der Waals]] attraction of atoms to the surface. Such interpretation leads to the estimate of the reflectivity
: <math>\displaystyle r \approx r_0\!\left( \frac \ell L C,\!~K\sin(\theta)\right)</math>,
where <math>~\ell~</math> is width of the ridges, <math>~L~</math> is distance between ridges, <math>\displaystyle ~\theta~</math> is [[grazing angle]], and <math>~K=mV/\hbar~</math> is wavenumber and <math>~r_0(C,k)~</math> is coefficient of reflection of atoms with wavenumber <math>~k~</math> from a flat surface at the normal incidence. Such estimate predicts the enhancement of the reflectivity at the '''increase''' of period <math>~L~</math>; this estimate is valid at <math>KL\!~\theta^2\ll 1</math>. See [[quantum reflection]] for the approximation (fit) of the function <math>~r_0~</math>.
 
===Interpretation as Zeno effect===
For narrow ridges with large period <math>L</math>, the ridges just blocks the part of the wavefront. Then, it can be interpreted in terms of the [[Fresnel diffraction]]<ref name="pra">
{{cite journal
| author= D.Kouznetsov | coauthors=H.Oberst
| year=2005
| title=Scattering of waves at ridged mirrors
| url=http://www.ils.uec.ac.jp/~dima/PhysRevA_72_013617.pdf
| journal=[[Physical Review A]]
| volume=72 |issue=1 | pages=013617
| doi=10.1103/PhysRevA.72.013617
|bibcode = 2005PhRvA..72a3617K }}</ref><ref name="fres">
{{cite journal
| author= H.Oberst
| coauthors=D.Kouznetsov, K.Shimizu, J.Fujita, and F. Shimizu
| year=2005
| title=Fresnel Diffraction Mirror for an Atomic Wave
| journal=[[Physical Review Letters]]
| volume=94 |issue=1 | pages=013203
| doi=10.1103/PhysRevLett.94.013203
| bibcode=2005PhRvL..94a3203O
}}</ref> of the [[de Broglie wave]], or the [[Zeno effect]];<ref name="zeno">
{{cite journal
| author= D.Kouznetsov
| coauthors= H.Oberst
| year=2005
| title=Reflection of Waves from a Ridged Surface and the Zeno Effect
| journal=[[Optical Review]]
| volume=12 | pages=1605–1623
| doi=10.1007/s10043-005-0363-9
| issue= 5
| bibcode=2005OptRv..12..363K
}}</ref> such interpretation leads to the estimate the reflectivity
:<math>~\displaystyle r \approx \exp\!\left(-\sqrt{8\!~K\!~L}~\theta\right)~</math>,
<!--where <math> ~K~</math> is wavenumber, <math>~L~</math> is period (distance between ridges) and
-->
where the [[grazing angle]] <math>\displaystyle ~\theta~</math> is supposed to be small. This estimate predicts enhancement of the reflectivity at the '''reduction''' of period <math>~L~</math>. This estimate requires that <math>~\ell/L \ll 1~</math>.
 
===Fundamental limit===
For efficient ridged mirrors, both estimates above should predict high reflectivity. This implies reduction of both, width, <math>\ell</math> of the ridges and the period, <math>L</math>. The width of the ridges cannot be smaller than the size of atom; this sets the limit of performance of the ridged mirrors.<ref name="nanoscope">
{{cite journal
| author= D.Kouznetsov
| coauthors=H. Oberst, K. Shimizu, A. Neumann, Y. Kuznetsova, J.-F. Bisson, K. Ueda, S. R. J. Brueck
| year=2006
| title=Ridged atomic mirrors and atomic nanoscope
| journal=[[Journal of Physics B]]
| volume=39 | pages=1605–1623
| doi=10.1088/0953-4075/39/7/005
| issue= 7
|bibcode = 2006JPhB...39.1605K }}</ref>
 
==Applications of ridged mirrors==
Ridged mirrors are not yet commercialized, although certain achievements can be mentioned. The reflectivity of a ridged atomic mirror can be orders of magnitude better than that of a flat surface. The use of a ridged mirror as an atomic [[hologram]] has been demonstrated.
In Shimizu's and Fujita's work,<ref name="holo">
{{cite journal
| author =F.Shimizu
| coauthors=J.Fujita
| year = 2002
| title = Reflection-Type Hologram for Atoms
| journal=[[Physical Review Letters]]
| volume=88 | issue = 12 |page=123201
| doi = 10.1103/PhysRevLett.88.123201
| pmid=11909457
| bibcode=2002PhRvL..88l3201S
}}</ref> atom holography is achieved via electrodes implanted into SiN<sub>4</sub> film over an atomic mirror, or maybe as the atomic mirror itself.
 
Ridged mirrors can also reflect [[visible light]];<ref name="nanoscope"/> however, for light waves, the performance is not better than that of a flat surface. An ellipsoidal ridged mirror is proposed as the focusing element for an atomic optical system with submicrometre resolution ([[atomic nanoscope]]).
 
==See also==
*[[Atomic mirror]]
*[[Quantum reflection]]
*[[Atomic nanoscope]]
*[[Zeno effect]]
*[[Matter wave]]
 
==References==
{{reflist}}
 
[[Category:Atomic, molecular, and optical physics]]

Latest revision as of 02:27, 16 December 2014

Hi there. Let me start by introducing the author, her title is Myrtle Cleary. He used to be unemployed but now he is a computer operator but his marketing never arrives. Doing ceramics is what adore performing. Her spouse and her live in Puerto Rico but she will have to transfer 1 working day or an additional.

Feel free to visit my blog: test.ithink-now.org