Optical signal storage

Fig. 16. Maximum achievable signal-to-noise ratio (SNR) on read-out of different writable optical data storage systems as a function of the writing energy (laser power) (121). SQS = Organic dye system (WORM) PC = phase change system (TeSeSb) MO = magnetooptical system (GbTbFe). See text.

Frequency Doubling. As the name implies, in frequency doubling a substance doubles the frequency of the incident laser radiation. This effect is important in telecommunications and optical data storage. For example, in telecommunications the most efficient way to transmit data is by using infrared radiation, e g., 1200 nm radiation from an indium phosphide laser [60], Detection of infrared radiation is inefficient. In contrast, visible radiation is much easier to detect but is an inefficient transmitter of data. Consequently, an important application of nonlinear optical (NLO) materials is to convert infrared radiation into visible and thus enable easier detection of the signal. 

Although a variety of commercial flow cytometers are available, all of them are composed of the same basic units, viz. fluid transport system, flow chamber, measurement region, excitation source and optics, optical and electronic sensors, collection optics, signals processing electronics, aind data display, storage and analysis system. 

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