World's First Green Laser Diode Will Lead To Better TVs, Pocket Projectors

Illustration for article titled Worlds First Green Laser Diode Will Lead To Better TVs, Pocket Projectors

A Japanese company named Sumitomo Electric Industries has developed "the world's first (pure) green laser diode." This development could result in TVs and pocket projectors that are superior "in terms of size, weight and power consumption."

Light sources using lasers for display applications, such as laser TV's and pocket laser projectors, are expected to have superior properties in terms of size, weight and power consumption. For this reason, R&D activities aimed at commercialization of these devices have expanded rapidly over the past several years. Up to now, only red and blue laser diodes were commercially available, while green lasers (*1) were obtained by frequency conversion of infrared lasers. Gallium nitride (GaN) semiconductors, commercially available for blue LEDs, are also expected to be the key material for light-emitting devices in the green region. However, the material has been plagued with a phenomenon where the luminance efficiency shows a rapid decline with increasing wavelength.

At Sumitomo Electric, we have overcome this problem by developing a GaN crystal which inhibits the efficiency drop, resulting in room temperature pulse operation of a laser diode emitting in the pure-green region at 531nm. It is the first green laser diode in the world.

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Sumitomo has applied for 60 patents on the technology, and are currently entertaining offers to use it in a wide range of applications. [Sumitomo via Crunchgear]

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DISCUSSION

nutbastard-old
nutbastard

uh... i thought the current 532nm green lasers were already, um, green.

wiki proves me wrong:

"The green light is generated in an indirect process, beginning with a high-power (typically 100-300 mW) infrared AlGaAs laser diode operating at 808 nm. The 808 nm light pumps a crystal of neodymium-doped yttrium aluminum vanadate (Nd:YVO4) (or Nd:YAG or less common Nd:YLF), which lases deeper in the infrared at 1064 nm. The vanadate crystal is coated on the diode side with a dielectric mirror that reflects at 1064 nm and transmits at 808 nm. The crystal is mounted on a copper block, acting as a heatsink; its 1064 nm output is fed into a crystal of potassium titanyl phosphate (KTP), mounted on a heatsink in the laser cavity resonator. The orientation of the crystals must be matched, as they are both anisotropic and the Nd:YVO4 outputs polarized light. This unit acts as a frequency doubler, and halves the wavelength to the desired 532 nm."

thanks for clearing that up, wiki.