news digest ♦ Lasers
In October 2013, Vienna University of Technology announced that its researchers had smashed the world record output power for quantum cascade terahertz lasers previously held by Massachusetts Institute of Technology (MIT). The Austrian team reported an output of 0.47 Watt from a single laser facet, nearly double the output power reported by the MIT team. The Leeds group has now achieved an output of more than 1 Watt from a single laser facet.
Linfield says, “The process of making these lasers is extraordinarily delicate. Layers of different semiconductors such as GaAs are built up one atomic monolayer at a time. We control the thickness and composition of each individual layer very accurately and build up a semiconductor material of between typically 1,000 and 2,000 layers. The record power of our new laser is due to the expertise that we have developed at Leeds in fabricating these layered semiconductors, together with our ability to engineer these materials subsequently into suitable and powerful laser devices.”
Giles Davies, Professor of Electronic and Photonic Engineering in the School of Electronic and Electrical Engineering, said: “The University of Leeds has been an international leader in terahertz engineering for many years. This work is a key step toward increasing the power of these lasers while keeping them compact and affordable enough to deliver the range of applications promised by terahertz technology.”
This work was mainly funded by the Engineering and Physical Sciences Research Council (EPSRC).
The full paper titled, «Terahertz quantum cascade lasers with >1 W output powers,» by Lianhe Li et al inElectronics Letters (2014) is available for download via the following link: DOI: 0.1049/el.2013.4035
Alfred Adams wins
optoelectronics prize for no strain, no gain
One of the research discoveries made by the professor was that the electronic band structure of quantum well lasers were improved by growing the active layer in a strained condition
Alfred Adams, Distinguished Professor of Physics at the University of Surrey, has been awarded the Rank Prize for his research into the structure of semiconductor lasers.
The findings of this research, now forms the basis of many every-day technologies, from DVD and Blu-ray
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www.compoundsemiconductor.net March 2014 storage, to optical fibre communications and the Internet.
In 1986, Adams and his team proposed that the electronic band structure of quantum well lasers could be significantly improved by deliberately growing the active layer in a state of strain. The results of this work now dominate the entire semiconductor laser market, with approximately one billion produced each year, for a market valued at around $5B.
Adams says, “I feel greatly honoured to receive this prestigious award. In doing so, I would like to honour the efforts of the many engineers who have made such a difference to every-day life through so many ingenious applications of our research.”
The prize was jointly awarded to Adams’s co-researcher O’Reilly, now working at the Tyndall Institute, and to Eli Yablonovitch at Bell Communications Research and Gordon Osbourn at Sandia National Laboratories, for their independent work.
II-VI Laser extends laser diode portfolio
The product line-up includes high speed and high power VCSELs, expanded pulse range for seed lasers and an expanded wavelength range for stacks and fibre-coupled multi single-emitters
II-VI Laser Enterprise GmbH, a subsidiary of II-VI Incorporated, will debut new products from its High Power Laser Diode and VCSEL portfolio at Photonics West 2014.
These devices are suited for consumer, fibre laser, and medical applications.
The products include 25G VCSEL Chips, High Power VCSEL arrays, 14xx nm and 10xx nm High Power Stacks, and expansion of industry-standard multi single- emitter fibre laser pumps to 793 nm wavelengths for thulium pumping.
High speed multimode 850 nm VCSELs target next generation optical interconnects and enable new applications which require increased data rates of 25 Gb/s per channel. The addition of high power VCSELs complements its innovative product portfolio geared at high volume sensing and illumination applications in consumer electronics markets.
Arranged in a 2D array, the High Power VCSEL can reach up to 2W optical power for illumination of larger volumes required in sensing applications such as time-
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