Optical unit

Optical unit

The Optical Unit is a dimensionless units of length used in optical microscopy. Because every diffraction limited system have their resolution proportional to wavelength / NA, it is convenient for comparison to use this unit. There are actually 2 units, one "axial" (along the optical axis of the objective) and one "radial".

In radial optical unit, the radius of the first Airy minimum (radius) is 3,77. It is also approximatively the same for the FWHM of Airy function.

Equation

u_{axial} = \frac{8 \pi n}{\lambda} sin^2(\frac{\alpha}{2}) z

v_{radial} = \frac{2 \pi}{\lambda} \frac{n sin \alpha}{M_{tot}} r

where :

  • n is the refractive index
  • λ is the wavelength
  • α the beam conus angle
  • M_tot is the total magnification (M is 1 if you want the size in the sample)

Note : n * sin α = numerical aperture

References


Wikimedia Foundation. 2010.

Игры ⚽ Поможем сделать НИР

Look at other dictionaries:

  • Optical power meter — in use An optical power meter (OPM) is a device used to measure the power in an optical signal. The term usually refers to a device for testing average power in fiber optic systems. Other general purpose light power measuring devices are usually… …   Wikipedia

  • Optical network unit — Pour les articles homonymes, voir ONU (homonymie). L optical network unit, (abbrév. ONU) est l équipement utilisateur chargé de terminer la fibre optique dans une solution FTTH.[1] Références …   Wikipédia en Français

  • Optical Carrier transmission rates — are a standardized set of specifications of transmission bandwidth for digital signals that can be carried on Synchronous Optical Networking (SONET) fiber optic networks.[1] Transmission rates are defined by rate of the bitstream of the digital… …   Wikipedia

  • Optical tweezers — (originally called single beam gradient force trap ) are scientific instruments that use a highly focused laser beam to provide an attractive or repulsive force (typically on the order of piconewtons), depending on the refractive index mismatch… …   Wikipedia

  • Optical character recognition — Optical character recognition, usually abbreviated to OCR, is the mechanical or electronic translation of scanned images of handwritten, typewritten or printed text into machine encoded text. It is widely used to convert books and documents into… …   Wikipedia

  • Optical cross section — or OCS is a value which describes the maximum amount of optical flux reflected back to the source. The standard unit of measurement is . It is dependent on the geometry and the reflectivity at a particular wavelength of an object. Optical cross… …   Wikipedia

  • optical character reader — (OCR) An automated mail sorting machine that interprets the address information on a letter size mailpiece and sprays the corresponding ZIP Code information onto the piece as a barcode. The OCR consists of a mail feed unit, transport unit,… …   Glossary of postal terms

  • Optical properties of carbon nanotubes — Contents 1 Terminology 2 Electronic structure of carbon nanotube 3 Van Hove singularities …   Wikipedia

  • Optical network unit — An optical network unit (ONU) is a device that transforms incoming optical signals into electronics at a customer s premises in order to provide telecommunications services over an optical fiber network. Contents 1 Definition 2 Usage 3 Optical… …   Wikipedia

  • Optical fiber connector — An optical fiber connector terminates the end of an optical fiber, and enables quicker connection and disconnection than splicing. The connectors mechanically couple and align the cores of fibers so that light can pass. Better connectors lose… …   Wikipedia

Share the article and excerpts

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