For outdoor signs and displays, acrylic, with its outstanding optical characteristics, weather resistance and formability, strongly dominates the picture.

For the further discussion, we shall thus assume an electron optical resolution of 80 Af and phosphor screen resolution of 60 Af.

For general computer use access technology such as screen readers, screen magnifiers and refreshable Braille displays has been widely taken up along with standalone reading aids that integrate a scanner, optical character recognition ( OCR ) software, and speech software in a single machine.

For example, the SEA-ME-WE 3 optical submarine telecommunications cable lands at both Medan and Jakarta connecting Europe with South eastern Asia ( several countries up to Japan ) and Australia ( Perth ).

For real, passive, optical systems, the output luminance is at most equal to the input.

For similar reasons, a bodyguard with a holster-carried, concealed weapon is typically not able to mount accessories onto the weapon, such as optical sights or forward handgrips.

For example, the Giant Magellan Telescope will have seven 8. 4 meter primary mirrors, with the resolving power equivalent to a optical aperture.

For example, the stability of bulk matter ( which consists of atoms and molecules which would quickly collapse under electric forces alone ), the rigidity of solids, and the mechanical, thermal, chemical, optical and magnetic properties of matter are all results of the interaction of electric charges under the rules of quantum mechanics.

For optical applications, this is characterized by the index of refraction.

For many materials ( for instance, semiconductors ), electrons move quickly from a high energy level to a meta-stable level via small nonradiative transitions and then make the final move down to the bottom level via an optical or radiative transition.

For example, the term subwavelength-diameter optical fibre means an optical fibre whose diameter is less than the wavelength of light propagating through it.

For planetary rings, the optical depth is the proportion of light blocked by the ring when it lies between the source and the observer.

* For an optical cavity consisting of two mirrors, confocal means that they share their foci.

For the optical regime, see beam divergence.

For a single-mode optical fiber, the cutoff wavelength is the wavelength at which the normalized frequency is approximately equal to 2. 405.

For an optical fiber, the effective mode volume is the square of the product of the diameter of the near-field pattern and the sine of the radiation angle of the far-field pattern.

For both families, the lowest-order solution describes a Gaussian beam, while higher-order solutions describe higher-order transverse modes in an optical resonator.

: Note: For optical fiber dispersion measurement purposes, the quantity of interest is group delay per unit length, which is the reciprocal of the group velocity of a particular mode.

For a Gaussian intensity ( i. e. power density, W / m < sup > 2 </ sup >) distribution in a single-mode optical fiber, the mode field diameter is that at which the electric and magnetic field strengths are reduced to 1 / e of their maximum values, i. e., the diameter at which power density is reduced to 1 / e < sup > 2 </ sup > of the maximum power density, because the power density is proportional to the square of the field strength.

For an optical fiber, the optical axis is along the center of the fiber core, and is also known as the fiber axis.

For example, using a long pulse length, it may possible to measure attenuation over a distance of more than 100 km, however in this case an optical event may appear to be over 1 km long.

For optical fibers, a power-law index profile is an index of refraction profile characterized by

For the same reason, the output fiber plate is planoconcave, its exposed flat side permitting contact photography if a permanent record is desired.

For phosphor to fiber and fiber to air surfaces, and assuming Af, we obtain Af percent.

For instance, nanotubes form only a tiny portion of the material ( s ) in ( primarily carbon fiber ) baseball bats, golf clubs, or car parts.

For example, the fibers in carbon fiber materials and rebars in reinforced concrete are oriented to withstand tension.

For this migration, ISDN services will be retired, and fiber optic services are recommended as an alternative.

For example, both PNGinc and International Turbine And Power, LLC use carbon fiber discs in their Tesla turbine designs.

For these purposes, manufactured rubber fiber is made as either an extruded round fiber or rectangular fibers that are cut into strips from extruded film.

For step index fiber, light entering the fiber will be guided if it falls within the acceptance cone of the fiber, that is if it makes an angle with the fiber axis that is less than the acceptance angle,

For step-index multimode fiber, the acceptance angle is determined only by the indices of refraction of the core and the cladding:

For example, sending ones and zeros across a wire, fiber, etc.

For plastic-clad silica ( PCS ) fibers, which have a strippable polymer cladding ( not to be confused with the polymer overcoat of an all-silica fiber ), the reference surface may be the core.

For a rectangular waveguide, the cutoff frequency is

For any waveguide in the form of a hollow metal tube, ( such as rectangular guide, circular guide, or double-ridge guide ), the wave impedance of a travelling wave is dependent on the frequency, but is the same throughout the guide.

For a waveguide entirely filled with a homogeneous dielectric medium, similar expressions apply, but with the wave impedance of the medium replacing Z < sub > 0 </ sub >.

For a waveguide or transmission line containing more than one type of dielectric medium ( such as microstrip ), the wave impedance will in general vary over the cross-section of the line.

For biophotonic applications the most commonly used laser diodes are edge emitting / ridge waveguide diodes, which are single transverse mode and can be optimized to an almost perfect TEM00 beam quality.

For example, a radio wave in a hollow metal waveguide must have zero tangential electric field amplitude at the walls of the waveguide, so the transverse pattern of the electric field of waves is restricted to those that fit between the walls.

For this reason, the modes supported by a waveguide are quantized.

For example, light travelling in an optical fiber or other dielectric waveguide forms hybrid-type modes.

For a given waveguide size ( such as X-band ), there is a cutoff frequency, and microwave radiation with smaller frequencies ( longer wavelengths ) cannot be propagated through the waveguide.

For the light to exit the ring resonator to the output bus waveguide, the wavelength of the light in each ring must be same.

For comparison, in the parabolic type of antenna a feedhorn at the end of a waveguide directs a conical beam of output energy toward the reflector, whence it is focused into a narrow collimated beam.