17 Jun 2002
Europe could learn a lot from the way that the US handles technology transfer, says Federico Capasso, head of physical research at Bell Labs. He talks to Phillip Hill about his ideas and his work on quantum cascade lasers.
From Opto & Laser Europe June 2001
As a young researcher, Federico Capasso left Europe to start a placement at Bell Labs in the US. Some 28 years later, he has worked his way up the ladder to the top of one of the world's most powerful research establishments. He believes that if Europe wants to mirror the economic success of the US, it needs to strengthen the links between pure research and industry.
How do you think Europe can learn from Bell Labs' success?
Europe's strength is that it has a broad base, a systematic school and university education system and a generally very well trained workforce in the science and technology sectors. This creates a vast pool of highly qualified and talented people.
Where Europe still has a lot to do is in strengthening the loop between scientific research (universities and other institutes, such as Max Planck), technological innovation (hi-tech start-up companies) and products (the more established medium/ large-size companies).
To do that a culture of risk and flexibility must be encouraged, along with the expansion of venture capital and the selective creation of private universities. More must be done to attenuate the sometimes rigid divisions between different disciplines and related university departments. In this sense, Europe can learn quite a bit from Bell Labs and the US in general.
What is your vision for optical research at Bell Labs?
It's important not to be an ivory tower of research and become isolated. We avoid this by keeping strong connections to our business units. We try to hire and retain the very best people from all over the world. I am trying to foster an atmosphere in which creativity, innovation and learning can thrive. It's essential that we maintain a broad interdisciplinary base with the right mix of basic and applied work, long-term and medium-short-term projects.
Apart from quantum cascade lasers, what areas of photonics do you think are most interesting at the moment?
Photonics based on organic materials could have a major impact due to their potentially very low cost. Last year, researchers in my organization demonstrated the first organic, electrically pumped laser, which had been for many years the Holy Grail of this field. Devices based on fast, nonlinear, optical materials will play an important role in communications for data rates beyond 40 Gbit/s on a single channel.
Looking further into the future, the big challenge or question is: will all optical processing, including functions such as optical multiplexing/demultiplexing and optical reading of packet headers, be possible and economically viable?
What does your work on QCLs involve?
We are helping to create a new chemical-sensor market through collaborations with universities and companies, such as Ford and Physical Science. The aggregated market could be USD 100 million or so. What we have shown so far with our laser is that one can detect traces of gases at parts per billion levels, which can be used for many applications. In my opinion, QCLs could find more than a niche. But I am pretty sceptical about telecoms applications since you have to keep mid-infrared detectors cooled to liquid-nitrogen temperatures to achieve the required high sensitivity.
There are many opportunities for device research in QCLs, most notably electrical beam steering, which is not possible in diode lasers because their active region is essentially neutral. In a QCL, electrostatic gates can be used to steer the output beam in space. We are working on terahertz QCLs operating at wavelengths greater than 50 µm, well into the far-infrared spectrum.
How did you make it to where you are now?
After finishing a PhD in physics at the University of Rome in 1973, with a thesis in quantum optics, I started work at the Fondazione Ugo Bordoni, a leading Italian research centre in telecommunications. I wanted to try something different and eventually I got a placement at Bell Labs in Holmdel, US. I was quickly hooked with the place and I said to myself that I wanted to stay that year at any cost because, in those days, Bell Labs at Holmdel was probably the world's strongest laboratory doing optics.
Then the opportunity came to move into a new group at Murray Hill. That's where I conceived band-structure engineering - the notion that entirely new electronic and optical materials could be designed and tailored for specific device applications using suitable semiconductor heterostructures made by MBE as building blocks. Quantum cascade lasers came much later (1994) and it was a long road.
The last 20 years at Bell Labs and elsewhere in the world have been the golden age of the rejuvenation of solid-state physics. In the 1970s the whole of the heterostructure field exploded and I was in the right place at the right time.
Would you ever go back to Italy?
Yes. At the right time and with the right opportunity.
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