By Christina Folz, OPN Managing Editor

On August 6, the Air Force Office of Scientific Research (AFOSR) continued the 2010 LaserFest celebration with its own event highlighting everyone's favorite technology this year. The event showcased the work of three OSA Fellows--Alan Willner, who works on optical communications at the University of Southern California; Margaret Murnane, who is studying high-peak-power physics with lasers at the University of Colorado, and Richard Miles, a Princeton professor who spoke about the role of lasers in aerospace. Two other laser experts--Robert Jones and Gary Teraney--described the important role that lasers are playing in the defense industry and in medicine. Each of the participants had been funded by AFOSR as grad students and went on to become distinguished leaders in the laser field.

For those who missed the event, or who simply sought more info, yesterday the AFOSR held a "bloggers roundtable" moderated by Howard Schlossberg, the program manager at AFOSR, to discuss the event and answer additional questions about the state-of-the art in laser technology. Schlossberg was joined by several of the event participants, including Willner and Miles.

And for those who missed THAT (including this humble blogger), you're in luck: A podcast and transcript of the roundtable are posted on the Department of Defense's blog. 

Schlossberg emphasized the importance of solid-state lasers in particular as pivotal to modern laser research and technology. "The primary emphasis by us and by others as well is in solid-state lasers, either on bulk solids, slabs pumped with semi-conducted lasers, or in optical fiber lasers," he said. He also called medical and materials processing two of the biggest application areas of lasers these days.

And don't worry--LaserFest is far from over. "At meetings, they'll have demonstrations and displays," Schlossberg said. "If you get on the LaserFest website, you'll see some of the terrific movies of early times." 

Party on!  

Contributed by: C. David Chaffee, Chaffee Fiber Optics

The celebration began anew this morning for Charles Kao, the father of fiber optics. This is the first time OFC/NFOEC has had the opportunity to honor him since he won the 2009 Nobel prize in physics, an award he shared with two other physicists. To our industry, he is the man, the kingpin, the major domo, the chairman of the board. In short, he is all that and a bag of chips.

Charlie has been honored before. He was so distinguished on the 25th anniversary of the seminal paper he wrote to launch the industry "Dielectric-fibre surface waveguide for optical frequencies" in the United Kingdom in 1966. This was also an OFC, the one in Baltimore in 1991. In fairness, Charlie co-authored the paper with George Hockham. But he was always the driving force, the passionate philosopher king who was given the providential vision the rest of the world lacked.

OFC/NFOEC does many things well. But at the top of the list is conveying a sense history for the fiber optics industry and this strengthens the sense of overall purpose and mission. Much of that is manifested by celebrations and awards such as this. Charlie's award and recognition comes in large part because what flowed out of the paper.

That's because the things in the paper were on-target. Four years after he predicted a silica fiber could transmit commerciable levels of light with acceptable loss (below 20 decibels per kilometer), Corning made it happen through an extraordinary effort. The accompanying lasers and detectors also were fashioned to make it work.

While humble in nature, Charlie has remained committed to fiber optics. This came through in the times I had the opportunity to interview him, also at OFCs. Once in the early 1980s, I asked him if fiber optics would ever be used for undersea transmission. "The oceans will be littered with fiber," he responded. This was six years before TAT-8, the first trans-oceanic fiber network was to be commissioned.

Charlie also predicted that people would use all the broadband that they could get their hands on, and that the costs would come crashing down. This was before we had dial-up service. And more than a few scientists have speculated that it is more than coincidence that Charlie's decision to settle in China some years ago and the rise of Huawei as a major fiber optics powerhouse.

In honoring Charlie this morning, Bell Labs pioneer Tingye Li recall a quote in 2004 that Charlie had made: "If you ask me how long we will see fibers being used, it may be 1,000 years without a replacement."

That's quite a legacy.

Posted by Christina Folz, OPN Managing Editor

According to a well-known sociological theory, everyone on the planet can be linked to any other person through six connections, or "degrees of separation." How well can you apply this concept to make connections between the following popular celebrities and optical pioneers? Please post your answers here as a "comment" or send them to us via e-mail at opn@osa.org.

1. Connect Edwin Land, founder of the Polaroid Corporation and inventor of the Polaroid camera (and namesake of OSA's Edwin H. Land Medal) to Dolly Parton, queen of country music, by no more than five people.

2. Connect Sir Arthur Eddington, an astrophysicist who brought the theory of relativity to the English-speaking world, to baseball great Joe DiMaggio, by no more than five people.

3. Connect Max Born, Nobel prize winner in physics (and namesake of OSA's Max Born Award), to socialite Paris Hilton, by no more than five people.

4. Connect Nicholas Negroponte, tech guru and 2007 OFC/NFOEC plenary speaker, to Ralph Lauren, famous American fashion designer, by no more than five people.

5. Connect Robert Metcalfe, Ethernet inventor and 2008 OFC/NFOEC plenary speaker, to martial arts star Chuck Norris, by no more than five people.

These puzzles were first published in Insight, OSA's staff newsletter. The OPN team would like to thank Annabella Goff and the OSA marketing team for allowing us to use them for OPN.

By Patricia Daukantas

For hundreds of years, stained-glass windows have decorated medieval cathedrals and awed onlookers with their intricate, translucent designs. Now a researcher in Australia has discovered that some windows that date back to the Middle Ages contain 21^st-century-style light-activated nanotechnology.

Medieval windows painted with pigments containing gold particles actually purify the air when lit by sunlight, according to Huai Yong Zhu, associate professor of chemistry at Queensland University of Technology in Brisbane.

Zhu and colleagues found that the gold nanoparticles found in many pigmented glass windows in Europe become activated when struck by sunlight and remove volatile organic compounds (VOCs) from the air. VOCs are light hydrocarbons that vaporize easily, and many of them are considered pollutants in the gas phase.

In Zhu’s words, sunlight causes the small gold particles to act like a “photocatalytic air purifier.” The solar energy boosts the magnetic field on the surface of the nanoparticles and this in turn breaks apart airborne VOCs. Zhu is interested in the process because it is solar-powered and thus energy-efficient.

Posted by Christina Folz, OPN Managing Editor

With 92 years of history under our belt, the Optical Society has accumulated scores of photos. Although we’ve captured many moments, we haven’t always captured the who, what and where information that must have seemed so obvious at the time the photo was snapped. Help us breathe new life into our images by providing your own imaginative captions to one of the images below. It could be a cartoon-style quote or a creative description of what you see. We’ll share your best captions in a future issue of OPN.

Send your captions to opn@osa.org or post them on our blog at www.osa-opn.org. (Remember to specify which image you are captioning…or don’t; it might be more fun that way.)

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By Deborah Herrin, OSA’s Director of Information Technology

Here are several very readable and enjoyable books about physics and the people who have shaped the science.

Galileo's Daughter: A Historical Memoir of Science, Faith, and Love, Dava Sobel

A biography of Galileo, with lots of great insights into the politics of the time, the role of the papacy and the internal struggle Galileo faced between his own religious beliefs and his scientific discoveries. I was reading this book during CLEO one year when I was invited to celebrate OSA past president Tony Siegman’s retirement. One of the presenters noted that scientists’ ability to measure was improving to such an extent that certain constants might prove to be variables in the future. I was struck by this juxtaposition of past and present: long-held truths that are proven to be incorrect.

Longitude: The True Story of a Lone Genius Who Solved the Greatest Scientific Problem of His Time, Dava Sobel

Since Sobel had impressed me with Galileo’s Daughter, I went back to this earlier book of hers–and was not disappointed. She describes how determining longitude required a precise determination of time; yet the most precise timekeepers relied on pendulums, which failed to work accurately when placed on a ship crossing the sea. After reading this book, I toured the U.S. Naval Observatory just up the street from OSA on the grounds of the vice president’s house. During the tour, you learn about time-keeping issues that the U.S. faced and how Western Union played a role; you see the atomic clock and the Internet clock, which shows how many computers are connecting to determine time every second; you visit a beautiful library where you’ll see OSA’s journals displayed; and, weather-permitting, you climb into the observatory to take a look through the telescope. After that, I was fortunate enough to take a trip to Greenwich, England, where I visited the observatory, saw many of Harrison’s timepieces and straddled the prime meridian.

Nobel Prize Women in Science: Their Lives, Struggles, and Momentous Discoveries, Sharon Bertsch McGrayne

OSA fellow Barry Masters turned me on to this book when he gave a brown bag lunch talk to OSA staff on one of the women in the book. This book presents the stories of 15 women who either won a Nobel Prize in science or played a significant role in Nobel-Prize winning research. The stories serve to highlight not only the science, but also women’s role in science and society as a whole. As an aside, when Maria Goeppert Mayer won the Nobel Prize in Physics in 1963, the local paper reported “La Jolla Mother Wins Nobel Prize.”

E=Mc²: A Biography of the World's Most Famous Equation, David Bodanis

This little book provides lots of information about physics and the people involved in the science leading up to nuclear physics. Did you know that Maxwell’s equations weren’t written by Maxwell? Or that several Nobel gold medals were dissolved in a solution in Denmark to avoid discovery by the invading Germans during WWII? The medals spent the war suspended in a solution and, after the war, the gold was recovered and made into new medals. One important tip as you read the book: read the notes at the back of the book as you go.

Brighter than a Thousand Suns: A Personal History of the Atomic Scientists, Robert Jungk

The previous two books, plus interest in learning more about Los Alamos, where many OSA members are, led me to this book. If you’re interested in this topic, you also should check out the play/movie “Copenhagen”, which deals with a meeting between two of the scientists–Bohr and Heisenberg. The controversy surrounding the play resulted in the Bohr Archive releasing early documentation related to that meeting.

Right now, I’m reading Measuring the World, by Daniel Kehlmann (translated from German). It’s a novel based on two Enlightenment-age scientists: Alexander von Humboldt and Carl Friedrich Gauss, the latter played a key role in optics.

Next up: The Canon: A Whirligig Tour of the Beautiful Basics of Science, by Natalie Angier. I heard the author and her husband (both science journalists and local residents) speak at the Marian Koshland Science Museum of the National Academies of Science in January. The premise of the book is what key concepts scientists wish the general public understood. I’m also reading Color, A Natural History of the Palette, by Victoria Finlay–this was a find at the Phillips Collection one lunchtime.

If you’ve read a good book related to science, please post a comment here to let us know about it!

By Patricia Daukantas

Polaroid lovers, you’re not alone.

Ever since the venerable Polaroid Corp. announced earlier this year that it will discontinue its remaining instant-film products, aficionados of the self-developing, one-of-a-kind prints have been banding together in cyberspace to celebrate the Polaroid as an artistic medium and share photos and tips.

A few days ago, the Rocky Mountain News in Denver (U.S.A.) paid tribute to Polaroids. Art writer Mary Voelz Chandler reminded readers of the many ways artists have used Polaroid film. In the same issue of that newspaper, a self-taught Polaroid photographer/artist ponders her technological future. The paper’s photography staff went out for one day with their old instant-film cameras and assembled the results into a video that includes a classic American television commercial for instant photography.

The New York-based blog Gothamist.com found a fellow Big Apple resident who has offered to send anybody, for a modest fee, an original Polaroid photo of something in New York City. Joe Howansky is also interested in trading his instant photos for Polaroids of exotic locales around the world.

The popular social-networking site LiveJournal has a community called the polaroids. More than 5,400 people have signed up to post their instant photos, old and new.

Another online community, Polanoid.net, was started by several Europeans who were, as they put it, “hungry for real analog, good smelling pictures in a digital world.” Users have uploaded more than 150,000 scanned, and sometimes manipulated, instant photos to that Web site.

Even CNN has gotten into the act. iReport.com—the cable news network’s beta site for “citizen journalism”—has a forum for sharing readers' favorite Polaroid snapshots. The photos that have already been uploaded include this poignant image of someone standing in front of the Lorraine Motel in Memphis, Tenn., where Dr. Martin Luther King Jr. was slain 40 years ago. A floral wreath on the upstairs balcony marks the spot.

Finally, in case you’re wondering how much longer Polaroid instant film will be around, the company has provided this list of projected availabilities of film types, plus the expiration dates of the last batches of products.

By Patricia Daukantas

If you’ve watched TV lately, you may have noticed an ad from a domestic beer company that made an extraordinary claim involving lasers. The company said it would project its logo on the near side of the moon during its full phase last Friday.

It didn’t take much Googling for me to debunk the “moonvertising” plan as a hoax dreamed up by an advertising agency team. But it raises a fascinating question: Is it possible to shine a laser beam onto the moon and see the light from Earth?

One entertainment executive says that a soft-drink company had similar moon-lighting plans for New Year’s eve in 2000, but the Federal Aviation Administration nixed the idea out of concern for aviation safety. Although the executive claims that scientists had done the math and found that such a feat was possible, he doesn’t present the research to back up the claim.

So I asked Tony Campillo, OSA’s senior director of science policy, to work out some back-of-the-envelope calculations. Tony has more than 40 years of experience in optics and photonics, as both an optical scientist with the Naval Research Labs and other institutions and as the former editor of the journal Optics Letters. His verdict: Making a light spot on the moon that people could see without assistance would likely require continuous laser power beyond anything we have on Earth right now.

Let’s imagine a single beam of green laser light originating on Earth’s surface and aimed at the moon. (The human eye is most sensitive to light of about 555 nm in wavelength, and green just happens to be the favorite color of the beer company that started this whole thing.) Assume that the outgoing beam is 3.5 m wide, as in the Apache Point Observatory laser-ranging program. After atmospheric distortion, the beam width would be 2 km at the moon, and about 90 percent of the light would reach the lunar surface.

But wait! The moon reflects only about 10 percent of the light that hits its surface. And even that, according to Tony, is scattered into a Lambertian pattern that covers an area that is 100 times the size of the Earth by the time it returns.

We know that the light-gathering part of the human eye—the dark-adapted pupil—is 1 cm wide at best, and let’s make a rough assumption that the diameter of the scattered beam is 1 million km wide when it hits the Earth. Thus, the naked-eye observer is catching only about 1 photon in every 10²².

How much light is needed for the human eye to see? In other words, what’s the threshold of human vision? I know more about astronomy than biology, so I’m a little shaky on that answer. Although some say that, in principle, the human eye should be sensitive to single photons of visible frequencies, in practice noise from both the visual field and the observer’s own neurological system gets in the way. Astronomers must subtract out background light when they are trying to measure the brightness of heavenly objects with their telescopes.

In Optics InfoBase, I found a 1919 (!) report by P.G. Nutting, OSA’s very first president. On the next-to-last page of the 25-pp. document, there’s a table that provides visual detection thresholds for sources of various areas; for the smallest source, the threshold light energy is 17.1 × 10^-10 erg/s, or 0.17 femtowatt (fW). (You could quibble that the table heading should be “power entering eye” instead of “energy entering eye” because the erg is the CGS unit for energy, not power. However, maybe unit accounting was different in 1919.)

Tony also guessed that an input of at least 1 fW from a continuous-wave (cw) laser would be needed to trigger sight in the human eye. Extrapolating to the originating laser, he guesstimated that a 100-GW cw laser would be needed to produce a visible spot on the moon.

Another way of thinking about the sensitivity of human vision involves the astronomers’ system of apparent magnitudes for measuring the brightness of objects in the night sky.

The apparent-magnitude scale is a logarithmic scale dating back to ancient days. The faintest stars that the human eye can see have a magnitude of 6, while stars with a magnitude of 1 are 100 times brighter than their 6^th-magnitude cousins. Nowadays, you might still be able to see 6^th-magnitude stars from a high desert on a clear night. However, from the typical suburb of a brightly lit American city, you would probably see only 3^rd-magnitude and brighter stars.

Suppose that the brightness of the one-pixel lunar display is 1^st magnitude. With the assumption that the pupil of the dark-adapted eye is 7 mm in diameter, Tony calculated that the eye will receive 200 photons/s from a 6^th-magnitude star and 20,000 photons/s from a 1^st-magnitude star. According to Tony, 1 W of green light corresponds to 2 × 10¹⁸ photons/s. By this line of reasoning, 0.01 fW of light from a 1^st-magnitude star hits the retina, and thus only a 1-GW cw laser would be required to make a visible dot on the moon.

In this case, Tony adds, his estimate assumes that the laser is painting a single 1^st-magnitude pixel on the darkened portion of a first-quarter or last-quarter moon. The beer commercial calls for shining an image on the full moon, which would require a lot more energy.

How does this estimate compare with existing lasers? The petawatt laser-fusion projects at the University of Rochester and Lawrence Livermore National Laboratory will generate huge energies – but over pulses in the nanosecond to picosecond range, not cw.

What would it take to build and fire a 100-GW cw laser? My best guess (from U.S. Energy Information Administration data) is that the United States generates roughly 4,000 GW of electricity every hour, but I could be way off. Would it really take 2.5 percent of the U.S. electrical supply to make a visible green dot on the surface of the moon?

Here’s where you come in. We’d like to ask for your feedback on our calculations and estimates. Many of the assumptions that Tony and I have made need to be refined, especially the size of the Lambertian scattered beam returned to the Earth. A better calculation of that beam size would have to take into account the cosine-square nature of the scattering to estimate the peak flux; that could change the guesstimate by an order of magnitude or more. Some questions to ask yourself:

§  What is the threshold at which a human on Earth could detect a bright spot on the moon? What is the optimal size of a pixel on the moon?

§  How much different would the experiment be if the bright spot was on the face of the full moon (which has an apparent magnitude of roughly −12) or a darkened region of the moon (between the quarter-moon and new-moon phases)? What is the required pixel brightness in each case?

§  What kind of a laser would be required to make this stunt work?

§  What would be the technical challenges involved in making such a laser?

Once you’ve tackled these yourself, you might pose these questions to your students as a thought experiment.

If any of your friends mention that they were disappointed about not seeing a logo on the moon, at least you’ll be able to explain why.

Image of the near side of the moon taken by the Clementine mission.

By Patricia Daukantas

My first camera was a Polaroid—back when the “colorpack” film had the peel-off chemical paper. I think it was a Model 320; it had bellows. The camera was the best Christmas present I got when I was 12 years old, and I immediately started taking pictures of my parents and grandmother. Letting the print-negative sandwich dangle from my fingers for exactly 60 seconds, then peeling the thing apart and setting the print to dry without getting chemicals on my skin, became a test of my ability to handle grown-up technology.

Of course, a year or two later, Polaroid Corp. came out with the first SX-70, and people didn’t have to fiddle with timers and smelly trash anymore. But those cameras were expensive, so I labored with my older Polaroid for a few more years until I got a hand-me-down Kodak camera from my father. Finally, I took up 35-mm photography in college.

Now comes word that Polaroid—or what’s left of the company after a bankruptcy several years ago—is discontinuing its remaining instant-film products. The company is willing to license its technology to other companies who might want to supply the ever-shrinking niche market for the instant-developing film. However, if no firms come forward, the remaining Polaroid devotees will be out of luck.

As the New York Times recounts, the self-developing Polaroid prints seemed like a wonder back in the days of film photography. And instant photography has a major connection to OSA history: As noted in the February 2007 issue of OPN, Polaroid founder Edwin H. Land chose the 1947 OSA annual meeting to demonstrate the technology for the first time. He was the hit of the OSA banquet, which took place the same month that his JOSA article was published explaining the process.

Legend has it that Land was inspired to develop instant photography when his daughter asked him why she couldn’t see the pictures he took immediately. Today’s children, surrounded by digital cameras, will never think to ask that question.


 
Polaroid Land Camera 360

Posted by Christina Folz, OPN Managing Editor

In perusing the daily news on optics.org, I came across an item titled, “Optics or Photonics: What’s in a Name?” It explained that the publisher of the Journal of Optics A had recently asked her editorial board whether they thought the name of the journal should be shortened or changed. Apparently there was some interest in integrating the word “photonics” into the journal’s name.

Which begs the question: Just what are optics and photonics anyway? And what’s the distinction between them? Although the Journal of Optics A editorial board didn’t reach consensus on a new name, they offered a multitude of opinions and insights. One member claimed that optics refers specifically to matters and equipment related to vision, whereas photonics (derived from the Greek word “photon”) is an umbrella term for any science dealing with light. According to these definitions, optics would seem to be a subdivision within photonics.

Other experts argue that it is the other way around: Optics is the older and broader discipline encompassing the relatively new field of photonics. Indeed, according to John Howard’s history column about OSA’s own name change controversy, the term “photonics” was introduced in the 1980s, coinciding with the emergence of several new areas within optics, including lasers, electro-optics, integrated optics and optical engineering. “The loosely defined word ‘photonics’ was analogous to the engineering of photons, just as ‘electronics’ had grown out of electron engineering,” Howard said.

In fact, in October 1989, OSA’s Committee on Society Objectives and Policy proposed to the Board of Directors that OSA change its name to “The Optics and Photonics Society” to reflect the evolving nature of the field. Although the Board voted to recommend the change, it reneged before the decision could be brought to a vote in the wake of a major backlash among Society veterans. Most of the opposition came from the classical and applied optics communities, which felt that the word “optics” already encompassed all wavelengths and processes involving optical radiation, so there was no need to adopt a gimmicky new word.

However, one significant modification was made as a result of this fray. The name of the Society’s membership magazine was changed from Optics News to Optics and Photonics News. Was this the right call? That’s what I’d like you to tell me through your comments and letters. In any case, you can rest assured that, whatever optics and photonics are, we’ve got them covered.