By Patricia Daukantas

With the exhibit hall (PhotonXpo) not opening until Tuesday, Monday at CLEO/IQEC had a distinctly academic feel to it. Each of the three tutorials I attended, including Theodor Hänsch’s early-morning talk, drew a standing-room-only crowd.

In his tutorial, Johannes F. de Boer of VU University in Amsterdam, the Netherlands, explained that optical coherence tomography (OCT) is analogous to ultrasound imaging, except that it uses infrared light instead of sound waves. Spectral-domain OCT, which was developed in the mid-1990s, has two to three orders of magnitude better sensitivity than the older time-domain OCT; in fact, it can be sensitive to a single photon. The technique’s speed makes it possible to take video-rate OCT images of structures such as the human retina, which is important in studying diseases such as age-related macular degeneration. Several types of human tissue -- collagen, muscle, nerve, tendon, cartilage -- are birefringent, so polarization-sensitive OCT imaging can show clear differences between normal and cancerous tissue.

Terahertz technology has been growing by leaps and bounds over the last 20 years, as Daniel R. Grischkowsky (Oklahoma State University, U.S.A.) described in his tutorial talk. Grischkowsky is a past winner of OSA’s Wood Prize and Meggers Award for developing terahertz time-domain spectroscopy (TDS) during his tenure at IBM Corp,’s Thomas J. Watson Research Center. Besides the well-known terahertz TDS applications in fundamental research and homeland security (explosives detection), industry can use TDS for quality control of pharmaceutical tablet coatings.

Among the other CLEO sessions I attended on Monday was a presentation by C.C. Yang (National Taiwan University, Taiwan) on OCT imaging of oral cancer in its different stages. I also learned from Desmond Jacob (Texas A&M University, U.S.A.) that melanoma happens to the human intestine and eyes as well as the skin; in fact, it’s the most common form of ocular cancer. Biopsy is the best means of diagnosing melanoma, but since it’s so difficult to biopsy the eye, non-invasive imaging techniques such as OCT could help catch the deadly disease before it spreads.

The first full day of CLEO wrapped up with an inspiring and well-attended plenary talk by a recent OPN feature article author, Edward Moses of Lawrence Livermore National Laboratory (U.S.A.), who showed the audience many cool photos of the “exciting and challenging journey” leading to the commissioning of the National Ignition Facility (NIF). His team has the ambitious goal of creating self-sustaining hydrogen “burns” over the next few years.

Further into the future, Moses envisions a power plant called the “LIFE engine” that would incorporate both nuclear fusion and nuclear fission -- a NIF-like machine surrounded by a “fission blanket” of conventionally spent nuclear fuel. Neutrons given off by the fusion would drive the fission reaction in the remaining fuel, so the whole thing could sit there and give off thermal energy for years or even decades without stopping, and it would greatly reduce the need for repositories of spent radioactive material.

As if that ides of a bright energy future wasn’t exciting enough, Moses closed his talk with the possible ways that NIF could help scientists explore the extreme conditions that occur in supernova explosions and the interiors of giant extrasolar planets. “I believe this field will be like high-energy physics was like in the 1930s and 1940s after [Edward O.] Lawrence invented the cyclotron, and it’s all driven by lasers and optical systems,” he said.

I was “tweeting” on Twitter.com throughout Moses’ plenary speech, and I will continue to do so today as PhotonXpo opens and the PhAST conference presents several exciting sessions on practical application of photonic technology. Follow @OPNmagazine on Twitter for updates throughout the meeting.

2009-06 June