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Chemistry LibreTexts

Common Devices

Barcode Readers, CD Players and Laser Pointers

  • Take advantage of the brightness and highly directional properties of laser radiation and often employ diode lasers.
  • Supermarket barcode readersa - As the light beam is scanned across the barcode, the white and black regions produce a modulation in the reflected light intensity. Lasers enable supermarket scanners to read barcodes rapidly and when presented over a range of angles.
  • CD (and DVD) playersb, c - Lasers are used to both encode and read information on CDs and DVDs. A smaller beam focus enables a greater density of information to be stored. Blu-ray technology uses a shorter wavelength than earlier technologies and hence provides greater information storage.

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