Researchers Develop World’s First 100W GaN Pulsed Laser
By integrating fundamental technologies on ultrashort pulse lasers and semiconductor laser diodes, the blue-violet laser could be used in next-generation large-capacity optical disc storage.
Researchers at Tohoku University, and Sony have jointly developed a blue-violet ultrafast pulsed semiconductor laser with dramatically improved peak laser beam output levels. The scientists claim that the output levels are 100 times better than the world’s current highest levels.
The research was conducted by Professor Hiroyuki Yokoyama of the New Industry Creation Hatchery Center (NICHe), Tohoku University, and Advanced Materials Laboratories, Sony Corporation.
This latest development is a gallium nitride (GaN) laser picosecond (ps) pulse source with a wavelength of 405 nm in the blue-violet region. It is capable of generating optical pulses of ultrafast duration of 3 ps, with ultrahigh output peak power of 100 W and repetition frequency of 1 GHz.
Ultra high-output laser devices combining solid-state laserssuch as mode-locked Ti: sapphire lasers and a second harmonic generation unit have previously been researched. However, in the past, the light source box itself was bulky and a specialist technician was required to ensure the stable operation of the laser.
The newly-developed semiconductor laser system, on the other hand, incorporates semiconductor diodes, which enables the size of devices such as the light source box to be drastically reduced. As such, this technology should be applicable to a far broader range of applications in the future than current systems.
The laser light source is capable of using a nonlinear optical process known as two-photon absorption, which occurs only as a result of high intensity optical pulses. This creates chemical and thermal changes in the vicinity of the lens where the laser beam is focused, in an area narrower than the diameter of the focus spot of the lens. It is anticipated that application of these properties will be possible in a wide range of fields such as three-dimensional (3D) nano-fabrication of inorganic/organic materials in the order of nanometers, and next-generation large-capacity optical disc storage.
The principles for applying this technology in next-generation large-capacity optical disc-storage were tested at Sony. The scientists created void marks with a diameter of approximately 300 nm on the interior of a plastic material, at intervals of 3 micrometers, and succeeded in reading these marks with a laser beam.
These results have been achieved through integration of Tohoku University’s fundamental technology on ultrashort pulse lasers, and Sony’s fundamental technology on semiconductor laser diodes.
From now on, the joint research program will focus on further developing its fundamental technology for creating even higher output and multi-functionality, while developing the practical applications of this technology to make these systems even more compact and stable.
Further details of these findings can be found in the latest edition of the US academic journal, ‘Applied Physics Letters’. (Appl. Phys. Lett. volume 97, issue 2, page 021101 (2010); doi:10.1063/1.3462942 (3 pages), Online Publication Date: 12 July 2010 )