Solid-State Light Sources

The dashed curve shows Ihe UV and bine output of a LED when driven Ughc 

Another light source is the laser diode. In ccmtrast to the LEDs, laser diodes emit mtnochromatic radiation. At present, laser diodes are available with wavelengths ranging from 630 to 1500 nm. It is likely that laser diodes with shorter wavelengths will soon become available. Laser diodes are convenient because the output is easily focused and manipulled. 

In contrast to the output of arc lamps oc incandescent lamps, the output of LEDs and laser diodes can be pulsed or modul ed. LEDs can be amplitude-modulated up to about 100 MHz, and laser diodes can be modulated to several gigahertz. The use of these light sources for time-resolved measurements will be described in Chapters 4 and 5. 

MoiioclifowttoislM edonai4Me(l ip)orcooca e(bM fttm) gnaing. Revised fiom Ref. 7. 

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Although electrophosphorescent polymer devices of the latter-type are attractive candidates for development of low-cost large-area solid-state lighting sources, they are still of a lower quality to that of their small-molecule-based PHOLEDs analogs. 

Phosphorescent (i.e., triplet) organic light-emitting diodes have very high EQEs/ and have been a subject of intense research and development activity worldwide. The realization of required luminous and power efficiencies, as well as long operafional lifetime, will enable phosphorescent OLED application in various displays for consumer electronics and as solid-state lighting sources. 

Ir complexes were also used to develop white OLEDs (WOLEDs) for large-scale production of solid-state light sources and backlights in liquid-crystal displays. Several device architectures have been introduced to achieve high brightness and efficiency in WOLEDs. By controlling the recombination current within individual... 

Czarske J (2006) Laser Doppler velocimetry using powerful solid-state light sources, review article. Meas Sci Technol 17 R71-R91... 

Eom lY (2005) Application of light emitting diodes as solid state light sources in analytical chemistry. Doctoral Dissertation, Texas Tech University... 

Schubert EF, Kim JK (2005) Solid-state light sources getting smart. Science 308 1274... 

K. Matsubara, U. Tanaka, H. Imago, M. Watanabe All-solid state light source for generation of continious-wave coherent radiation near 202 nm. J. Opt. Soc. Am. B 16, 1668 (1999)... 

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