Two years later, in 1933, Ruska built an electron microscope that exceeded the resolution attainable with an optical ( lens ) microscope.

Two of the primary methods for identifying rocks in the laboratory are through optical microscopy and by using an electron microprobe.

* Two or more mirrors that form an optical resonator.

Two compounds that are enantiomers of each other have the same physical properties, except for the direction in which they rotate polarized light and how they interact with different optical isomers of other compounds.

Two gyrotropic materials with reversed rotation directions of the two principal polarizations, corresponding to complex-conjugate ε tensors for lossless media, are called optical isomers.

Near the source of the leat there is a curious optical illusion ; viewed from the opposite bank of the West Dart River between Two Bridges and Wistman's Wood, it appears to flow uphill.

Two optical resonators constructed from crystalline sapphire, controlling the frequencies of two lasers, were set at right angles within a helium cryostat.

Two methods for storing information on the film were employed: " magnetic IX " and " optical IX ".

Two types of optical tracking mechanisms exist:

Two other stars, located at angular separations of 44 and 370 arcseconds, are likely optical companions that are not physically associated with the system.

Two streams of stars seem to cascade down like waterfalls due to compositing | optical effects.

Two of the larger factors are: quantum efficiency, which indicates how well incident optical photons are absorbed and then used to generate primary charge carriers ; and total leakage current, which is the sum of the dark current and photocurrent and noise.

Two sets of independent follow-up spectroscopy data suggested that this was again another optical transient rather than a supernova, possibly an outbursting Luminous Blue Variable star according to one spectrum, as earlier predicted from the nature of the candidate mid-infrared progenitor.

Two scientific awards have been created in his honour ; the David Bates Medal of the European Geophysical Society is awarded yearly for outstanding contributions to planetary and solar system science, and the Institute of Physics have the David Bates Prize, awarded in even dated years, for distinguished achievement in atomic, molecular, optical and plasma physics.

Two special cases of the Kerr effect are normally considered, these being the Kerr electro-optic effect, or DC Kerr effect, and the optical Kerr effect, or AC Kerr effect.

It is equipped with a number of instruments, including the Two Degree Field facility ( 2dF ), a robotic optical fibre positioner for obtaining spectroscopy of up to 400 objects over a 2 ° field of view simultaneously ; the University College London Échelle Spectrograph ( UCLES ), a high-resolution optical spectrograph which has been used to discover many extrasolar planets ; and IRIS2, a wide-field infrared camera and spectrograph.

Two of the optical telescope domes can be seen on the roof.

Two gyrotropic materials with reversed rotation directions of the two principal polarizations are called optical isomers.

Two different types of proximity fuze can be fitted: the standard Strizh ( Swift ) optical fuse, which can be replaced with a Kolibri active radar fuse.

Two CCD star sensors were used for optical position sensing of guide stars and attitude determination of the spacecraft.

Two mirror images of a chiral molecule are called enantiomers or optical isomers.

Two low frequency control tones were printed on the film's mono optical or magnetic track ; from the projector, the tones entered a control box in the projection booth, which fed low frequency pseudorandom noise to 1, 600 watt BGW 750 audio amplifiers driving the speakers.

Two such points are called a stigmatic pair of the optical system.

Two generations of this chip were produced.

Two dominant fish and chip shops facing the quay supply the large numbers of tourists and daytrippers who come to Wells throughout the year.

Two generations of this chip were produced.

Two additional registers are included for setting any address the CPU wishes to read and the chip alternates between outputting addresses for display generation and the display set for CPU access.

Two LPARs may access memory from a common memory chip, provided that the ranges of addresses directly accessible to each do not overlap.

In chemistry and optical engineering, photons are usually symbolized by hν, the energy of a photon, where h is Planck's constant and the Greek letter ν ( nu ) is the photon's frequency.

These include photon scanning microscopy ( PSTM ), which uses an optical tip to tunnel photons ; scanning tunneling potentiometry ( STP ), which measures electric potential across a surface ; spin polarized scanning tunneling microscopy ( SPSTM ), which uses a ferromagnetic tip to tunnel spin-polarized electrons into a magnetic sample, and atomic force microscopy ( AFM ), in which the force caused by interaction between the tip and sample is measured.

An optical depth of 1 corresponds to a mean free path, which is the distance, on average that a photon travels before scattering from a dust grain.

Since optical frequencies are far beyond the manipulation-capacity of any feasible electronic circuit, all photon detectors are inherently energy detectors not oscillating electric field detectors.

The term also applies to photon counting in optical devices, where shot noise is associated with the particle nature of light.

When these are absent, however, optical detection is said to be " photon noise limited " as only the shot noise ( also known as " quantum noise " or " photon noise " in this context ) remains.

They show explicitly that the necessary condition to realize a negative ( pulling ) optical force is the simultaneous excitation of multipoles in the particle and if the projection of the total photon momentum along the propagation direction is small, attractive optical force is possible.

The primary quantity that characterizes the electronic structure of any crystalline material is the probability of photon absorption, which is directly related to the imaginary part of the optical dielectric function ε ( ω ).

* 1928 Chandrasekhara Raman studies optical photon scattering by electrons

** Emanuel Knill, Raymond Laflamme, and Gerard Milburn show that optical quantum computing is possible with single photon sources, linear optical elements, and single photon detectors, launching the field of linear optical quantum computing.

* Single photon emitter for optical fibers developed.

The beamline includes X-ray optical devices which control the bandwidth, photon flux, beam dimensions, focus, and collimation of the rays.

This system of ordinary differential equations relates the number or density of photons and charge carriers ( electrons ) in the device to the injection current and to device and material parameters such as carrier lifetime, photon lifetime, and the optical gain.

This formulation requires one equation for the carrier density, and one equation for the photon density in each of the optical cavity modes:

In optical spectroscopy, the energy absorbed to move an electron to a more energetic level and / or the energy emitted as the electron moves to a lower energy level is in the form of a photon ( a particle of light ).

Sometimes, the excited state is metastable, so the relaxation back out of the excited state is delayed ( necessitating anywhere from a few microseconds to hours depending on the material ): the process then corresponds to either one of two phenomena, depending on the type of transition and hence the wavelength of the emitted optical photon: delayed fluorescence or phosphorescence, also called after-glow.

Sometimes, a direct T < sub > 0 </ sub > → S < sub > 0 </ sub > transition occurs ( also delayed ), and corresponds to the phenomenon of phosphorescence ( note that the difference between delayed-fluorescence and phosphorescence lies in the difference in the wavelengths of the emitted optical photon in a S < sup >*</ sup > → S < sub > 0 </ sub > transition versus a T < sub > 0 </ sub > → S < sub > 0 </ sub > transition ).