Ridged mirror

Ridged mirror

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".cite journal
author= F.Shimizu
coauthors=J. Fujita
title=Giant Quantum Reflection of Neon Atoms from a Ridged Silicon Surface
journal=Journal of the Physical Society of Japan

Reflectivity of ridged atomic mirrors

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 hypothesis about wave properties of reflected atoms.

caling of the van der Waals force

The ridges enhance the quantum reflection from the surface,reducing the effective constant ~C~ of the van der Waals attraction of atoms to the surface. Such interpretation leads to the estimate of the reflectivity: displaystyle r approx r_0!left( frac ell L C,!~Ksin( heta) ight),where ~ell~ is width of the ridges, ~L~ is distance between ridges,displaystyle ~ heta~ is grazing angle, and ~K=mV/hbar~ is wavenumber and ~r_0(C,k)~ is coefficient of reflection of atoms with wavenumber ~k~ from a flat surface at the normal incidence. Such estimate predicts the enhancement of thereflectivity at the increase of period ~L~; this estimate is valid at KL!~ heta^2ll 1. See quantum reflection for the approximation (fit) of the function ~r_0~.

Interpretation as Zeno effect

For narrow ridges with large period L, the ridges just blocks the part of the wavefront. Then, it can be interpreted in terms of the Fresnel diffraction cite journal
author= D.Kouznetsov | coauthors=H.Oberst
title=Scattering of waves at ridged mirrors.
journal=PRA | volume=72 | pages=013617 | year=2005
] cite journal
author= H.Oberst | coauthors=D.Kouznetsov, K.Shimizu, J.Fujita, and F. Shimizu
title=Fresnel Diffraction Mirror for an Atomic Wave
journal=PRL | volume=94 | pages=013203 | year=2005
] of the de Broglie wave, or the Zeno effect cite journal
author= D.Kouznetsov | coauthors= H.Oberst
title=Reflection of Waves from a Ridged Surface and the Zeno Effect
journal=Optical Review | volume=12 | pages=1605–1623 | year=2005
] ; such interpretation leads to the estimate the reflectivity

:~displaystyle r approx exp!left(-sqrt{8!~K!~L}~ heta ight)~,

where the grazing angle displaystyle ~ heta~ is supposed to be small. This estimate predicts enhancement of the reflectivity at the reduction of period ~L~.This estimate requires that ~ell/L ll 1~.

Fundamental limit

For efficient ridged mirrors, both estimates above should predict high reflectivity. This implies reduction of both, width, ell of the ridges and the period, L. The width of the ridges cannot be smaller than the size of atom; this sets the limit of performance of the ridged mirrors cite journal
author= D.Kouznetsov
coauthors=H. Oberst, K. Shimizu, A. Neumann, Y. Kuznetsova, J.-F. Bisson, K. Ueda, S. R. J. Brueck
title=Ridged atomic mirrors and atomic nanoscope
] .

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,cite journal
title = Reflection-Type Hologram for Atoms
author =F.Shimizu
journal = PRL
volume = 88
number = 12
pages = 123201
numpages = 4
year = 2002
month = Mar
publisher = American Physical Society
format = subscription required
] atom holography is achieved via electrodes implanted into SiN4 film over an atomic mirror, or maybe as the atomic mirror itself.

Ridged mirrors can also reflect visible light cite journal
author= D.Kouznetsov
coauthors=H. Oberst, K. Shimizu, A. Neumann, Y. Kuznetsova, J.-F. Bisson, K. Ueda, S. R. J. Brueck
title=Ridged atomic mirrors and atomic 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).

ee also

*atomic mirror (physics),
*quantum reflection,
*atomic nanoscope,
*Zeno effect
*de Broglie hypothesis


Wikimedia Foundation. 2010.

Look at other dictionaries:

  • Mirror — looking glass redirects here. For other uses, see Looking Glass (disambiguation). This article is about wave reflectors (mainly, specular reflection of visible light). For other uses, see Mirror (disambiguation). A mirror, reflecting a vase A… …   Wikipedia

  • Atomic mirror — In physics, an atomic mirror is a device which reflects neutral atoms in the similar way as the conventional mirror reflects visible light.Atomic mirrors can be made of electric fields or magnetic fields,cite journal… …   Wikipedia

  • Quantum reflection — is a physical phenomenon involving the reflection of a matter wave from an attractive potential. In classical physics, such a phenomenon is not possible; for instance when one magnet is pulled toward another, you do not expect one of the magnets… …   Wikipedia

  • Atomic de Broglie microscope — Fig.1. Proposal for the Helium microscope by.[1] The atomic de Broglie microscope (also atomic nanoscope, neutral beam microscope, or scanning helium microscope when helium is used as the probing atom) is an imaging system which is expected to… …   Wikipedia

  • Institute for Laser Science — The Institute for Laser Science is a department of the University of Electro Communications, located near Tokyo, Japan.LocationThe Institute for Laser Science is located at 1 5 1 Chofugaoka, Chofu, Tokyo, 182 8585, Japan. The coordinates are (+35 …   Wikipedia

  • Matter wave — This article is about the quantum mechanical concept of all matter having a duality model as a wave. For the ordinary type of wave propagating through material media, see Mechanical wave. In quantum mechanics, a matter wave or de Broglie wave (… …   Wikipedia

  • Atom optics — (or atomic optics) is the area of physics which deals with beams of cold, slowly moving neutral atoms, as a special case of a particle beam. Like an optical beam, the atomic beam may exhibit diffraction and interference, and can be focused with… …   Wikipedia

  • De Broglie hypothesis — In physics, the de Broglie hypothesis (pronounced /brœj/, as French breuil, close to broy ) is the statement that all matter (any object) has a wave like nature (wave particle duality). The de Broglie relations show that the wavelength is… …   Wikipedia

  • Quantum Zeno effect — The quantum Zeno effect is a name coined by George Sudarshan and Baidyanaith Misra of the University of Texas in 1977 in their analysis of the situation in which an unstable particle, if observed continuously, will never decay.Citation | last =… …   Wikipedia

  • Fresnel diffraction — In optics, the Fresnel diffraction equation for near field diffraction, is an approximation of Kirchhoff Fresnel diffraction that can be applied to the propagation of waves in the near field.[1] The near field can be specified by the Fresnel… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.