A team of University of Tokyo researchers has developed and demonstrated a prototype laser semiconductor which emits blue light from its surface at room temperature. The chip can be used to accelerate the reading and writing of
digital video disks.
Previously the group had developed a blue violet laser which could only work at temperatures of minus 200C, but the process has been refined and new materials added to allow room-temperature operation.
The surface-emitting laser sandwiches an indium gallium nitride luminous layer between two layers of oxides. Blue laser light with a wavelength of 399 nanometers is emitted from the upper surface when light strikes the bottom of the chip.
Nichia Chemical Industries Ltd has already test-shipped a conventional-type, blue-light laser chip, which emits a thin ray of light from the side. The big advantage of the new surface-emitting model is that more than one can be joined together to enable several simultaneous functions and speed up data reading and writing.
