Optical coupling

Oq, and, if die trap cycle field couples to die 0 long-range molecular state [57], die second Condon point occurs at 60 <3q. Survival against radiative relaxation improves greatly because die optical coupling occurs at much shorter... 

Spectral Gamma Ray Log. This log makes use of a very efficient tool that records the individual response to the different radioactive minerals. These minerals include potassium-40 and the elements in the uranium family as well as those in the thorium family. The GR spectrum emitted by each element is made up of easily identifiable lines. As the result of the Compton effect, the counter records a continuous spectrum. The presence of potassium, uranium and thorium can be quantitatively evaluated only with the help of a computer that calculates in real time the amounts present. The counter consists of a crystal optically coupled to a photomultiplier. The radiation level is measured in several energy windows. 

In order to address the possible influence of positional disorder, we have chosen to analyze the way basic operations such as translations and rotations affect the properties calculated for highly symmetric configurations. This approach could provide guidelines to prevent the loss of significant optical coupling between the ground state and the lowest excited state, and hence the quenching of luminescence in the solid state. 

In a regime of strong interaction between the chains no optical coupling between the ground slate and the lowest excited state occurs. The absence of coupling, however, has a different origin. Indeed, below 7 A, the LCAO coefficients start to delocalize over the two chains and the wavefunclions become entirely symmetric below 5 A due to an efficient exchange of electrons between the chains. This delocalization of the wavcfunclion is not taken into account in the molecular exciton model, which therefore becomes unreliable at short chain separations. Analysis of the one-electron structure of the complexes indicates that the... 

We note dial highly correlated calculations performed on isolated slilbene indicate that the first excited stale strongly optically coupled lo die ground stale is mil (he lowest in energy, in contrast to the INDO/SCI results [44 however, emission lakes place from the strongly coupled excited stale when relaxation effects are considered thus, the exact ordering of the lowest two excited stales in slilbene does not modify the main conclusions of our study. 

However, the method will not enhance the external quantum yield of the LED, moreover, proper optical coupling between the layers has to be achieved in order not to decrease the QY loo much [61. One of the obvious problems is the principal requirement of having the ITO-covered glass substrate between the color converter and the cmitLer layer. This can also lead to color bleeding, an effect where the emitter layer excites not only the conversion layer, it is supposed to address but also neighboring ones. 

A sealed-tube neutron generator, utilizing the deuterium-tritium reaction is the source of fast (14 MeV) neutrons, and a 8 x 3 1 Nal scintillation detector, with three optically coupled photomultipliers, is used to measure the >ray signal... 

The potential energy curves (Fig. 1), the non-adiabatic coupling, transition dipole moments and other system parameters are same as those used in our previous work (18,19,23,27). The excited states 1 B(0 ) and 2 B( rio) are non-adiabatically coupled and their potential energy curves cross at R = 6.08 a.u. The ground 0 X( Eo) state is optically coupled to both the and the 2 R( nJ) states with the transition dipole moment /ioi = 0.25/xo2-The results to be presented are for the cw field e(t) = A Yll=o cos (w - u pfi)t described earlier. However, for IBr, we have shown (18) that similar selectivity and yield may be obtained using Gaussian pulses too. 

Therefore, investigators have shown considerable interest in the adoption of the Langmuir-Blodgett technique, or its modifications, to make molecular electronic devices using, in particular, as an active component, a light-transducing protein, such as BR. In fact, the ability of BR to form thin films with excellent optical properties and the intrinsic properties themselves make it an outstanding candidate for use in optically coupled devices. 

Four different types of tasks are performed by automation. Two involve the sequencing of valves and pumps Involved 1n the setup and completion of the designed experiment through the operation of the test and hydraulic fluid systems. The other tasks involve the control of the temperature bath and data collection. To perform these tasks, a1r-actuated solenoids and optically coupled sol Id-state relays are used. These devices are controlled by an electrical circuit consisting of the device connected 1n series with a power supply and a channel on the actuator card In the HP 3497. The power supply 1s either 24 VDC for use with the solenoids or 5 VDC for the solid-state relays. The actuator output channel acts as a simple on/off switch which allows power to be supplied to the solenoid or relay when closed. The logic of the circuit 1s controlled by application programs running on the local HP 1000. 

Fig. 9.3. Optical alignment of the fiber-optic output with respect to the microscope axis (black line). A close up is shown of the side-port of the Axiovert 200 microscope and fiber-optic coupling of a modulated 514 nm laser source. Left the fiber output (coming from the right) is aligned onto the microscope axis enabling wide-held excitation. Right the fiber output is aligned slightly off axis, but sufficient to induce TIRF. The scale of the picture can be inferred from the optical table M6 screw mounts separated by 1 inch.

Figure 5. Single-point IR sensor head layouts a transmission probe with fibre coupling b transflectance probe with variable pathlength and single fibre coupling c (diffuse) reflection probe with single illumination fibre and collection fibre bundle d two-reflection ATR probe with fibre-optic coupling e multi-reflection ATR probe (DiComp -type) f ATR fibre...

The secondary electrons emitted from the sample are attracted to the detector by the collector screen. Once near the detector, the secondary electrons are accelerated into the scintillator by a positive potential maintained on the scintillator. Visible light is produced by the reaction of the secondary electrons with the scintillator material. The emitted light is detected by a photomultiplier tube, which is optically coupled to the scintillator via a light pipe. The PMT signal is then transferred to the grid of a cathode ray tube (CRT). Data collection... 

An efficient optical coupling to the WGMs is instrumental in order to harvest the full potential of the high-2 droplet resonators. In most reported experiments, the droplet resonators are probed by free-space excitation, where, e.g., a Gaussian laser beam excites resonator modes and scattered light or fluorescence is detected. This approach... 

The prism and shde may be optically coupled with glycerol, cyclohexanol, or microscope immersion oil, among other liquids. Immersion oil has a higher refractive index (thereby avoiding possible TIR at the prism/coupling liquid interface at low incidence angles), but it tends to be more autofluorescent (even the extremely low fluorescence types). 

Astratov, V.N., Franchak, J.P., and Ashili, S.P., 2004, Optical coupling and transport phenomena in chains of spherical dielectric microresonators with size disorder, Appl. Phys. Lett. 85(23) 5508-5510. 

Tai, C.-Y., Unal, B., Wilkinson, IS., Ghanem, M.A., and Bartlett, P.N., 2004, Optical coupling between a self-assembled microsphere grating and a rib waveguide, Appl. Phys. Lett,84(18) 3513-3515. 

MICRO-OPTICAL COUPLING OF FIBRE AND PHOTONIC CRYSTAL WAVEGUIDE... 

Detectors are used to convert X-ray flux into an electrical signal, which can then be digitized and stored. For imaging cabinet X-ray systems, the detectors usually consist of a folded linear array of scintillators optically coupled to photodiodes. Typically, 500-1000 such detector elements are present for single-energy imaging... 

The availability of integrated circuits paved the way for the next generation ofX-ray inspection system. These units featured a side-shooting fan beam of X-rays incident on an extended array of scintillators optically coupled to photodiodes or phototransistors. The resulting low-level electric currents were then amphfied, integrated, and electronically sampled and digitized. Such systems were under development by ScanRay and Picker in 1977. By 1979, Picker was marketing... 

Fiber-optic-coupled spectrophotometers (single beam and double beam) are the best choice for on-line analyses. The advent of nonsolarizing optical fiber has made possible on-line analyses in which the spectrophotometer may be located remotely from the process and light is carried to/from the process by the optical fiber. A rugged probe or flow cell provides the sample interface. 

Figure 5.24 Example fiber-optic-coupled flow cell sample system.

Figure 5.26 Example fibre-optic-coupled in-line transmission cell (Reproduced courtesy of Specac Limited, www.specac.co.uk).

Figure 5.27 Fibre-optic-coupled insertion transmittance probe (Reproduced courtesy of Axiom Analytical Inc, www.goaxiom.com).

The latter is particularly the case for laser instruments where attention to optical interfacing is essential, and often features specialized optical hber based optical coupling. 

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