High-output power

An important development in the 1980s was the multiple stripe laser, capable of emission of high output powers. A number of stripes are placed on a bar perhaps 1 cm wide the output of the different stripes is coupled so that the device may be regarded as a single laser. Bars having continuous output up to 20 W are available in the aluminum gallium arsenide system. A number of bars may then be stacked to form two-dimensional arrays with high values of output power. 

In some cases, due to the high output power of lasers which are often used as a light source, the dye may be susceptible to photobleaching. In addition, some NIR dyes may undergo spectral changes when exposed to sunlight over several hours and may also have a limited shelflife, even when kept in the dark. These are some of the present limitations that can be overcome with further development of new NIR dyes. One way to increase stability of NIR is the incorporation of the polymethine chain into cyclic... 

Its comparatively high output power on a single transition. 

A very interesting device regarding high output power is the photochemical iodine laser 411) where excited iodine atoms are formed by photodissociation of CH3I. Pulses with 5 MW peak power and 5 nsec duration have been produced which could be further amplified in two stages up to 10 W. Energies of 1 K Joule seem to be attainable 412). 

The systems can have a high output power weight ratio. Second- and third-generation equipment will have a very high output power weight ratio. 

By using either a continuous or pulsed source of radiation and by measuring the amount of radiation absorbed by the reaction products, it is possible to determine product state distributions. The source of radiation can either be monochromatic (resonance lamp or laser) or broad-band (flash lamp or arc lamp) used in conjunction with a form of monochromator at the detector. The amount of absorption is monitored by an appropriate photosensitive or energy-sensitive detector. Particular care must be taken in the case of resonance lamps to avoid self-reversal of the output of the source, as this will complicate the quantitative analysis of product densities [17]. Similarly, laser sources must not be operated at such high output powers that the transitions involved become saturated, as this also complicates the analysis. Absorption measurements can be used for a wide range of reaction products, both ground and excited states of atoms, radicals and molecules [9,17, 22]. 

The thrust of research on optical recording media is to achieve high sensitivity and long-term stability simultaneously. Since these are conflicting properties, a compromise between sensitivity and stability is usually made. In the future, the availability of visible semiconductor lasers with high output power will relax the sensitivity requirement. Finally, the recording media should require no further processing steps (Jamberdino, 1981). 

The voltage limits of the amplifier are controlled by the power supplies. They usually are quite close to the supply values. For most devices, the limits are 13-14 V. Currents will be supplied freely to a load until the current limits are reached, typically at 5-100 mA. Special devices with larger current or voltage output limits are available, but high output power in operational amplifier circuits is usually obtained by booster stages, as described below. 

The high output power of pulsed CO2 lasers allows excitation of high vibrational levels by multiphoton absorption, which evenmally may lead to the dissociation of... 

A fluorescence detection system is quite similar to aUV-visible absorbance detection system, except that a laser light source or a LED with high output power is used, a set of band-pass filters must be present to select appropriate wavelengths for the excitation and emission light to achieve precise measurements, and fluorescent tags must be attached to the target particles if necessary. 

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