By Patricia Daukantas

To wind up OPN’s coverage of CLEO/QELS 2010, I would like to spotlight some of the interesting things that I didn’t get a chance to write about during the conference.

Weather Guy to Lidar Specialists: Please Help

A meteorologist at California State University at Chico (U.S.A.) presented a list of opportunities for lidar researchers to help improve his group’s technology for studying atmospheric aerosols.

Shane D. Mayor uses a direct-detection infrared lidar instrument dubbed REAL (for Raman-shifted Eye-safe Aerosol Lidar) to study how particulate matter moves with air currents. He has participated in several simulations of bacterial agent plumes – this knowledge could be important in the case of a biological weapons attack.

REAL operates at 1,543 nm, which Mayor said is in the “sweet spot” between shorter-wavelength retinal hazards and insufficient detector performance above 2 µm. The 1.5-µm zone also offers such desirable qualities as low molecular scattering, low background radiation from the sky, and compatibility with telecom components. Mayor and a colleague designed a Raman shifter for converting the REAL Nd:YAG laser output from 1,064 nm to 1,543 nm (Appl. Opt. 46, 2990).

Unfortunately, the flashlamps on REAL’s pump laser need replacement every 20 million shots or 23 days – at $200 each, that amounts to $6,350 per year, Mayor noted. Also, the CSU-Chico lidar setup requires a tractor-trailer for transportation, but Mayor’s goal is to shrink that down to fit in a more mobile van.

Mayor listed a number of ways that optical scientists could help improve REAL. They include:

• Reduce or eliminate flashlamp replacement.
• Increase efficiency by reducing power consumption and waste heat.
• Further reduce the mass of the beam steering unit mirrors, which are now 14 kg each.
• Develop a high-precision pulse energy monitor that can measure shots to ± 1 percent.
• Figure out how to monitor beam divergence continuously on the fly.

What Makes Counterfeit Money Funny?

Can measuring the intrinsic fluorescence lifetime of U.S. paper money distinguish between phony bills and the real thing? Researchers from Yale University (U.S.A.) believe that this technique could be used for forensic identification of counterfeit money.

The key, according to biomedical engineers Michael J. Levene and Thomas Chia, is that the paper for all U.S. currency comes from a single source. Although the exact “recipe” for that paper is secret, it has a very consistent fluorescence lifetime “signature” that differs from that of other types of papers made from wood, cotton and linen pulp. U.S. currency ink is essentially non-fluorescent, although the serial numbers on bills scatter light. (Inks on some non-U.S. currency, like the Mexican 100-peso note, do fluoresce, so that could be important in detecting foreign fakes.)

The researchers used a custom-built two-photon microscope, with an excitation wavelength of 735 nm, to study U.S. currency – mostly $100 banknotes, since they are the highest-valued bills targeted by counterfeiters. (They also tested some lower denominations as a control group.) They also tested three kinds of counterfeit bills provided to them by investigators: digital scans onto printer paper, counterfeit bills printed on cotton-linen-blend paper, and so-called “bleached” low-denomination bills that were illicitly reprinted with a higher denomination.

Levene and Chia didn’t know the exact provenance of the counterfeit money. “They [investigators] don’t like us to hold onto the bills for more than a few hours and won’t tell us much about where they came from, and we’re not going to make our own,” Levene said.

All the genuine currency notes had consistent short- and long-lifetime components to their fluorescence. The printer-paper fakes had only the longer-lifetime component. Other counterfeit bills had noticeably shorter long-lifetime components.

The testing group included bills dating back to the 1970s, and because the United States has been using the same paper supplier for so many decades, the two-component intrinsic fluorescence lifetime signature is “remarkably consistent” over the years, Levene said.

Small and Big Lasers

Qi Qin of the Massachusetts Institute of Technology (U.S.A.) and colleagues at two other labs built a tunable terahertz “wire laser” whose cavity is much narrower than its operating wavelength. The researchers tuned the laser by moving either a metal or dielectric “plunger” outside the laser cavity. (The gold plunger shifted the wavelength shorter and the silicon plunger made the operating wavelength longer.)

The group’s first design, as reported in the original CLEO proceedings, achieved 137 GHz of tuning centered on 3.8 THz. To get rid of the static friction that made the plunger stick and jump, they designed a MEMS-type plunger made up of layers of gold, silicon and silicon dioxide. The revised laser, only 10.5 µm wide, registered a total shift of 330 GHz between 3.85 and 4.2 THz, or about 8.5 percent. Such lasers could be used to detect explosives, which have spectroscopic “fingerprints” in the terahertz range, according to Qin.

On the opposite end of the laser size spectrum, Textron Defense Systems (U.S.A.) is building a 100-kW laser as part of the Pentagon’s Joint High Power Solid State Laser Program. Invited speaker Alex Mandl traced the history of Textron’s efforts from its initial “membership in the kilowatt club” (1.2 kW achieved in February 2004) to its laser’s performance of more than 100 kW in final government tests (exactly how much more, he couldn’t divulge).

Textron calls its technology ThinZag because the beam path inside the laser zigzags through a comparatively thin slab of ceramic (not crystalline) Nd:YAG material. The final laser configuration consists of six ThinZag 15-kW-class lasers in series (yes, 15 × 6 = 90, but again, there may have been other technological tweaks to get it over the 100-kW mark).

Social Media and Postdeadline Papers

I would like to tip my hat to the four CLEO/QELS bloggers – Jim van Howe, Ksenia Dolgaleva, Xiaoyu Miao and David Nugent – who have been contributing to the conference’s social media hub. If you haven’t done so already, please check out their coverage of CLEO/QELS.

Van Howe, a professor at Augustana College in Rock Island, Ill. (U.S.A.), blogged about a couple of postdeadline papers I missed because the room was full and the entryway was clogged. (The paper numbers, though, were QPDA5 and QPDA6.) Since those papers seemed to generate a lot of buzz, I’ll summarize them here.

The group that presented QPDA5, from Yale University (U.S.A.), said that an arbitrary body can be made perfectly absorbing at discrete frequencies, thanks to the interaction of optical absorption and wave interference. “It is thus the time-reversed process of lasing at threshold,” A. Douglas Stone and colleagues wrote.

In QPDA6, Evgenii Narimanov of Purdue University and two colleagues from Norfolk State University (all U.S.A.) found a new approach to the “blacker than black” phenomenon of radiation absorption: something called hyperbolic metamaterials. Hyperbolic dispersion means that a metamaterial has negative electric permittivity in the direction perpendicular to its surface and positive electric permittivity parallel to its surface. The researchers tested their ideas by building an experimental array of silver nanowires.

In the postdeadline session where I did find a space to put myself, Aleksandr Biberman of Columbia University (U.S.A.) described his group’s demonstration of a 40-Gbps electro-optic switch for photonic networks-on-chip (paper CPDA11). Such CMOS-compatible switches will be needed as more photonic networks are built inside the computer as well as between computers. Biberman worked with researchers from both Columbia and Cornell University (U.S.A.).

2010-05 May, CLEO/QELS, Lasers cleo, cleo10, lasers, lidar, metamaterials, social media, optics, atmospheric optics, terahertz technology, biomedical optics, laserfest

By Patricia Daukantas

One of the highlights of the CLEO exhibit hall has been the extraordinary display of vintage lasers from all stages of the 50-year history of the technology. This exhibit has been on display earlier this year, but we still have been pleased to see it at CLEO 2010.

One of the biggest contributors to the laser-history exhibit was Robert Alan Hess, a holography consultant who is also a huge old-tech-gear buff. He told me that he acquired many of the vintage lasers through online auctions, company selloffs, and simple word-of-mouth. For a small bit of cash, more than one aging scientist in the process of home decluttering has been happy to part with an old instrument that’s been gathering dust for many years.

Of course, other people and organizations who have played important roles in laser history also lent their items to the exhibit. For example, here is a replica of Theodore Maiman’s first working ruby laser in front of his lab notebook from May 1960. Both items are on loan from his widow, Kathleen Maiman.

Here is one of the early commercial CO₂ lasers from Coherent Radiation Laboratories. Under the company’s logo, somebody once attached a red label: “Gift to Schawlow Lab.”

In honor of today’s 30^th birthday of the Pac-Man video game, here’s another blast from the past. On the top shelf of this display case are two laser pointers from the 1980s. They were considered “portable” because they were battery-powered and had a power switch on the side of the housing. Imagine wielding this during your next talk? These pointers must have had the heft and feel of “Star Wars” light sabers (or at least the things that the live actors used for their light-saber fights before the CGI people added in the “beams”).

Several times during CLEO Expo, Hess demonstrated a working flashlamp-pumped ruby laser that’s not much different from Maiman’s pioneering device. The ruby laser Hess was using is a commercial model that Hughes Research Laboratories—Maiman’s employer—put on the market in April 1962. Only about 100 of these lasers were manufactured and sold before technology raced ahead of the model.

Hess said his Hughes ruby laser was sold sometime in the early 1960s to Texas Instruments, which used it for sensor experiments, then declared it surplus around 1972. A man bought it and kept it, for whatever reason, until 2006, when he sold it to a laser show artist. That guy, in turn, soon put it up for auction on eBay and Hess got it.

In the photo below, Hess is using a modern He-Ne laser, hidden under the black cover, to align the optical path of the 1962 ruby laser. He will attempt to use the ruby laser pulse to punch a hole in a vintage razor blade that he found in his parents’ medicine cabinet.

Sure enough, the ruby laser punched a 120-m m-wide hole in the razor blade!

The vintage laser contained a pink ruby rod about 1.5 inches long and 3/8 inch wide, surrounded by the original helical xenon flashlamp and a diffuse white reflector. Hess isn’t sure how much life is left in the old flashlamp, but it worked every time during CLEO.

The laser history exhibit had a lot of other cool items: the first supermarket laser scanner, diode and DPSS lasers, and slabs of glass made especially for the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory. I’m hoping that we at OPN will be able to put together an online gallery of all these photos I’ve taken during my week at CLEO.

I hope all our CLEO/QELS attendees have a safe journey home, and we’ll see you all next year in Baltimore, Maryland!

2010-05 May, CLEO/QELS, Lasers, Lasers, CLEO, Optics history lasers, cleo, cleo10, laser history, laserfest, 3d, cleo/qels, vintage lasers

By Patricia Daukantas

I thought I’d give my readers a quick summary of some of the interesting sessions I’ve been attending at CLEO/QELS and CLEO:Applications.

As you might expect, both terahertz technology and metamaterials are really hot topics right now. Put them together and you get a well-attended session on terahertz metamaterials. Hui Tao, Richard D. Averitt and colleagues at Boston University (U.S.A.) built structurally reconfigurable metamaterials using the techniques of micro-electro-mechanical-systems (MEMS) fabrication.

Basically, the BU team built an array of tiny split-ring resonators (SRRs), 72 x 72 m m in size, with an in-plane periodicity of 100 m m. These things are made of bianisotropic gold-silicon nitride and they tilt up and down like an array of little flaps, thus controlling the beam of terahertz radiation passing through the metamaterial. (Note: Tao recently finished his Ph.D. and is a postdoctoral fellow at Tufts University, also in Massachusetts, U.S.A.)

Also on the topic of metamaterials, a German group led by Benjamin Reinhard of the University of Kaiserslautern studied surface terahertz surface waves on an array of copper SRRs. Their experiment’s unit size was 41 x 41 m m, or about 1/7 of a wavelength at 1 THz, and every sixth row of the array was removed. They modeled the metamaterial as a thin-slab waveguide and found that their experimental (See the May 1 issue of Optics Letters -- vol. 35, p. 1320 -- for more details on their work.)

I always enjoy the Market Focus sessions (PhAST in past years, CLEO:Applications in 2010), and this year’s have been no exception.

At an energy-related session, Corey Dunsky, president of Aeos Consulting Inc. (U.S.A.), made some powerful arguments that lasers can help lower manufacturing costs and improve the conversion efficiency of photovoltaic panels. In one example he offered, single-step laser doping is well-positioned to be the best way of fabricating selective emitters on the surfaces of crystalline silicon solar panels. Andrew Masters, a vice president of Veeco Instruments (U.S.A.), described how his company’s atomic force microscopes can quantify solar cells’ efficiency to within plus-or-minus 0.5 percent.

Another session of Market Focus examined various optical methods for detecting chemical threats and explosives.

Price Kagey of Surface Optics Corp. (U.S.A.) reviewed a whole list of technologies -- laser-induced breakdown spectroscopy, Raman spectroscopy, quantum-cascade-laser-based heating and thermography, broadband heating and emission spectroscopy, and hyperspectral imaging -- and found that all of them came up short in one way or another (cost, eye safety, ease of remote deployment, etc.).

Dan Strellis of Rapiscan Systems Ltd. (United Kingdom) said his company is working with both terahertz and X-ray technologies to develop a scanner specifically for shoes, so that airline passengers wouldn’t have to take off their shoes at security checkpoints. According to Adam Bingham of ICx Technologies (U.S.A.), workable systems for detecting explosives at checkpoints will probably require pairs of systems, one for wide-area scanning and a different kind of detector for zooming in to provide “high-confidence confirmation.”

Today (Thursday in California) is the final day that CLEO’s exhibit hall is open, so I’ll be making a final swing through there -- and getting one last glimpse of the laser history exhibit (more on that shortly). Tonight features the three concurrent CLEO/QELS postdeadline paper sessions.

One thing I’ve forgotten to mention in previous posts is a special LaserFest presentation: reprints of a collection of early quantum-electronics papers from the Soviet Union. It’s titled “Beginning of the Laser Era in the USSR,” and some of the articles have been translated into English for the first time. You can find it on the LaserFest website, Optics InfoBase or

this link.

2010-05 May, CLEO/QELS, Lasers, Lasers, CLEO cleo, lasers, cleo10, cleo/qels, laserfest, metamaterials, terahertz technology

By Patricia Daukantas

Most molecular biologists stare down at throngs of their tiny subjects the way an aerial photographer captures a large pack of runners at a marathon. Steven Block wants to focus on a single molecule, just like zooming in to study the guy who broke out of the pack to win the marathon four times.

That’s how Block, a professor of both biology and physics at Stanford University, set the stage for his Wednesday morning CLEO plenary talk on single-molecule biophysics with optical tweezers. I’m not an expert on biology by any stretch -- even my high-school biology class is sadly out of date now -- but I’ll try to convey what he said as best I can.

RNA polymerase, the enzyme that produces RNA, is a sophisticated nanomachine, and scientists would like to know how it works. Humans have three or four kinds of RNA polymerase; it’s the stuff that makes our cells differentiate themselves by function, even though each chromosome has the same DNA. On the scale of proteins, RNA polymerase is pretty big -- about 3,300 amino acids -- but on the scale of things in general, it’s pretty small -- roughly 10 nm big.

Optical tweezers are “the closest thing humans have made to a tractor beam,” Block said after showing his grad-school-days video of a single bacterium stuck in an optical trap. His experiments with then-grad-student Will Greenleaf and colleagues, as I understand them, involved setting up two tiny dielectric spheres in side-by-side traps and stretching a single DNA molecule back and forth between them. They did this in order to study riboswitches, which are non-coding messenger RNA (mRNA) strands that control gene expression by changing structure when they selectively bind to a molecule. More experiments are forthcoming, even though Greenleaf is now a postdoc at Harvard University.

David Awschalom, the QELS plenary speaker from the University of California at Santa Barbara, talked about something else that’s darned tiny: single electron spins in semiconductors.

Much like photons, electron spin ensembles exhibit coherence in doped semiconductors. Much research into semiconductor spins has been done with low-temperature ensembles, Awschalom said, but tremendous progress has been made over the last five years into the study of single spins in solid-state matter.

Diamond -- that glittering crystal of carbon -- is a CMOS-compatible (both p- and n-type) semiconductor with remarkable thermal properties. Awschalom and his colleagues study synthetic diamonds with certain impurities called nitrogen-vacancy centers, in which two neighboring points of the carbon crystal lattice are replaced by a nitrogen atom and a gap with no atom. (Diamond gemstones with many of these impurities look yellowish.)

Again, the way I understand these experiments, the team shone polarized light through a diamond at room temperature and used a confocal microscope to spatially map the photoluminescence pattern and thus measure the single spins. In a paper published last December in Science, the team described how these single spins can flip on the order of 1 ns, which is about five times faster than the RAM in a modern desktop computer operates. Paradoxically, performance improves with increasing temperature -- not the way conventional electronic devices work.

Arrays of these tiny spins within diamonds could have many uses in quantum computing and communications -- and many other kinds of defects in diamonds have yet to be explored. To keep up with Awschalom’s research group, check out http://www.physics.ucsb.edu/~awschalom.

2010-05 May, Biomedical optics, CLEO/QELS, Lasers, Lasers, CLEO cleo, cleo10, cleo/qels, laserfest, biomedical optics, molecular biology, dna, optical tweezers, optical manipulation, diamonds, semiconductors

By Patricia Daukantas

Light is a visual phenomenon, and the scientists and engineers who study it work long hours … but when it comes time for relaxation, some of them really rock out in a totally different medium: music.

Fortunately for us CLEO attendees, these singers and players showed off their gifts last night at a special LaserFest concert called “Lasers Rock!” We heard rappers and rockers, jazz and blues on the stage of the San Jose Civic Auditorium.

The idea for this concert came from CLEO co-chair Claire Gmachl of Princeton University, according to emcee Sir Peter Knight (OSA 2004 President). He said the acts reflect the Society’s diversity in age and musical taste.

First up were the young but professional duo Phat Photonics, who rapped about DNA, sang the blues about global warming, and performed a laser-rock song they wrote for the occasion.

Phat Photonics consists of Dan Gareau, of the Oregon Health and Sciences University, and Martin Zarzar, who also plays in a band called Pink Martini. When not rapping and rocking, Gareau studies confocal microscopy for non-invasive detection of melanoma. The duo will record their three tunes for their upcoming album, “Science Rock.”

Next came jazz guitarist Yoshiaki Nakajima, who, when not noodling on the strings searches for the perfect fiber frequency comb at Fukui University in Japan. I’m no musical expert, but I’d say his influences include Pat Metheny and the Dave Matthews Band, and his third piece was pure tone poetry.

According to Knight, Eric Hansotte plays in bars around Silicon Valley to support his day job in optical engineering. Wielding his acoustic guitar like a pro, Hansotte played several folk-rock songs, including a pean to women with brains (“I like a girl who will drool over Fleming’s left-hand rule….”).

It took a few minutes for the stage hands to set up for the next act, so I grabbed a beer at the bar in the lobby. I noticed the gallery of portraits of some mighty famous entertainers who have graced the stage of the Civic Auditorium: Dylan, Stones, Who, Santana, Sinatra. But our optical researchers didn’t appear intimidated by the challenge of following in their footsteps.

When I got back into the hall, Hansotte and OSA’s immediate Past President, Tom Baer, had joined the Free Lunch Band on stage for a jam. Then Hansotte and Baer left the stage and the band—which hails from Lawrence Livermore National Laboratory—ripped through several covers of popular rock songs. I didn‘t catch their individual names, but they proved that a lab that can make really big lasers can also give off a really big wall of sound.

After that smokin’ hot set, Brian Kolner of the University of California at Davis cooled things down a few degrees with his brand of brilliant folk-rock on his 12-string acoustic guitar.

Finally, Bob Fisher and Steven Block took the stage for an excellent country-bluegrass set on various stringed instruments. Fisher is one of the program co-chairs of this year’s CLEO, and Block has to be back at the Civic Auditorium early this morning to deliver his CLEO plenary address, “Single-Molecule Biophysics with Optical Tweezers.”

To wrap up the night, Baer came back out on stage with his harmonicas—“First Harmonic” and “Second Harmonic”—and joined his colleagues for a sweet rendition of “Sweet Georgia Brown.” Sweet indeed!

2010-05 May, CLEO/QELS, Lasers, Lasers, CLEO cleo, cleo10, lasers, laserfest, lasersrock, cleo/qels, music, science rock

By Patricia Daukantas

Charles Hard Townes—Berkeley professor, Nobel laureate in 1964, OSA Honorary Member since 1970—probably needed no introduction to the attendees at yesterday’s LaserFest History Symposium at CLEO/QELS. But moderator Joseph Giordmaine still gave him a kind introduction, and Townes in turn paid a gracious tribute to Ted Maiman on the 50th anniversary of his ruby laser. Then Townes delivered some personal anecdotes about his own lengthy career—some of which you may not already have heard.

Albert Einstein first described stimulated emission in 1917, and the phenomenon occurs in outer space, Townes pointed out. “If we had looked carefully, we could have discovered them there,” he added. Instead, the ideas for masers and lasers pretty much lay dormant for a few decades. “How blind we are to new ones,” he said.

Townes said that his radar engineering work during World War II turned out to be important to his scientific career, because in dealing with radar interference from water vapor in the atmosphere, his studies led to the start of microwave spectroscopy.

After telling the famous story of how he got a crucial insight while sitting on a park bench, Townes recalled how he was delivering a lecture when Jim Gordon rushed in the room to shout about their maser, “It’s working!” Professor and students all rushed out of the classroom to see what was happening in the lab.

Also, while Townes was on sabbatical leave in the 1950s, he visited Tokyo, where he talked to a biologist who was studying population fluctuations among single-cell organisms. “That’s just what I was working out for the laser,” Townes said. “I just had to add one term.” This talk with the mathematical biologist gave him critical insight into managing energy-level populations.

Townes’ brother-in-law, Arthur Schawlow, was the one who came up with the idea of two parallel plates because he had been working with Fabry-Pérot interferometers. In 1958, they asked Schawlow’s employer, Bell Labs, to patent their ideas … but the telephone company’s research laboratory refused to file an application “because light had never been used for communications.” So Schawlow and Townes went ahead with the publication of their famous theoretical “optical maser” paper in the Physical Review.

The next two LaserFest History Symposium speakers, C. Kumar N. Patel and Marshall Nathan, highlighted two main branches of laser research since the days of Ted Maiman: high-power gas lasers and the ubiquitous semiconductor lasers. Patel, who invented the carbon dioxide laser at Bell Labs, now develops applications for quantum cascade lasers through his own company, Pranalytica Inc. of Santa Monica, Calif. (U.S.A.). Nathan, who worked for IBM and then joined the University of Minnesota (U.S.A.), said that the development of semiconductor lasers in the 1960s was due to a lot of hard work and not much serendipity.

At the end of the symposium, the subject “zoomed out” from tiny lasers to the biggest lasers in the world—namely, the 192 gigantic beam lines of the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory, just a few miles from the conference site in San Jose, Calif.

“I was 10 years old when the laser was invented, and it was the perfect time to be born,” said NIF director Edward Moses. As soon as he saw his first helium-neon laser in 1968, he knew that he wanted to make laser physics his life’s work.

John Nuckolls -- a Livermore physicist who is still with the lab after 55 years—proposed to use lasers for fusion energy as soon as Maiman’s working laser was announced in 1960, Moses said. He remains optimistic that NIF will achieve ignition in the next couple of years, develop a prototype inertial fusion energy plant by 2020, and see the technology go commercial by 2030. “It sounds fast, but look at the laser,” he added.

Indeed.

As I said in the previous blog post, the historical symposium drew a large crowd, especially considering that it was the first CLEO event other than the short courses. Among the audience I saw at least five other OSA Past Presidents besides Tony Siegman, plus numerous other OSA volunteers and Fellows. During the coffee break I ran into OSA Honorary Member John L. “Jan” Hall, another one of our Nobel laureates for laser-related work. He told me that he was really enjoying the proceedings.

What would a birthday be without a party? Following the symposium, LaserFest held a reception at which attendees could mingle with the distinguished speakers, and we were offered the most adorable LaserFest cupcakes!

CLEO/QELS and CLEO:Applications continuing today with a full day of technical sessions, followed by the first of two plenary sessions this evening. In addition to this OPN blog, you can follow the action on CLEO’s social media page. Enjoy!

2010-05 May, CLEO/QELS, Lasers, Lasers, CLEO cleo, cleo10, lasers, laserfest, laser history, charles hard townes, laserfest history symposium

By Patricia Daukantas

CLEO knows how to throw a party!

Fifty years to the day—and roughly the hour—after Theodore “Ted” Maiman fired up the first laser, a sizable crowd of CLEO/QELS attendees listened raptly to a series of historical recollections from some of the early laser pioneers and other distinguished speakers.

If Ted Maiman had been here, of course, he would have had pride of place, but he died three years ago this month. Instead, his widow, Kathleen Maiman of Vancouver (Canada), recalled his professional focus and his personal warmth.

“Advances often flow in small steps, but with the laser, it was a quantum leap, a giant leap,” Kathleen Maiman said. She said that her husband was a maverick and a contrarian who did not buy into Arthur Schawlow’s widely believed 1959 statement that a ruby laser would not work.

“Ted believed it would be very difficult to make a laser, but not impossible,” Kathleen Maiman said. With his solid background in both physics and engineering—his father had been an electrical engineer who let the boy tinker in his lab for fun—he built a successful laser weighing just a few pounds in a project that cost Hughes Research Labs only $50,000, including salaries. Because of Maiman’s success, Ali Javan has said that IBM Corp. revived his multi-million-dollar gas laser project.

Ted Maiman disliked the headline that followed the Hughes press conference about the first laser—“L.A. Man Invents Death Ray.” Ironically, the laser has gone on to be a healing ray in ophthalmology and a helpful ray in other areas, such as driving the Internet, cutting through steel, manipulating single atoms and even amusing pet cats.

“Ted had to cast off conventional wisdom to follow his own convictions,” said Kathleen Maiman. “Ted’s ruby laser has changed the world with elegance, simplicity and practicality.”

Jeff Hecht, an author of many technology-related books and a frequent contributor to OPN, reviewed some of the early maser-related work in the 1950s. He compared Maiman’s invention to Chihiro Kikuchi’s 1957 ruby maser: it weighed 2.5 tons, required liquid-helium cooling to 4 K and was the size of a large desk.

By the time of the first Quantum Electronics Conference in September 1959—where Schawlow made his negative pronouncement about ruby as a lasing medium—people were beginning to doubt whether the laser would ever work, Hecht said. That prompted Maiman to do his own preliminary experiments with rubies, and unlike other scientists, he found that ruby’s fluorescence was nearly 100 percent.

Once Maiman assembled the components of his ruby laser, it worked the first time he tried it—“no small accomplishment in laser experiments,” Hecht said. (Or in many other scientific experiments, I might add.) Maiman’s design was a whole new approach to laser design: pulsed operation, high gain, well engineered and easy for other researchers to replicate.

OSA’s 1999 President, Tony Siegman of Stanford University—a member of the steering committee for that September 1959 conference -- reviewed some of the pre-maser developments that made masers and lasers possible, such as the invention of closed microwave cavities and the Fabry-Pérot interferometer.

“Maiman was imbued with that ‘just get it done’ spirit you find here in California,” Siegman said.

In the early 1960s, laser research progressed rapidly; Siegman paid tribute to the crucial mode calculations by Gardner Fox and Tingye Li, which suggested that curved mirrors would lower the losses in confocal cavities. Ironically, in the 1940s and 1950s, Fox had create the first microwave relay links for long-distance phone calls, and by the time he died in 1992, the laser technology on which they had worked had made those microwave relays obsolete. (Li, another OSA Past President, is still living in Colorado and skiing with his grandchildren, Siegman noted.)

When Maiman published about his first ruby laser, the scientific community was astounded because of simplicity of the components used, the characteristics of the energy levels of the laser transition, and the pulsed-by-flash-lamp type of laser excitation, said Orazio Svelto of the Politecnico di Milano, Italy.

OSA Honorary Member Nicolaas Bloembergen, a 1981 winner of the Nobel Prize for contributions to laser spectroscopy, gave a series of personal anecdotes about the early days of lasers and the people involved. He and his wife, Huberta, met Charles and Frances Townes at an award banquet, and Frances Townes showed off the ruby pendant her husband had made for her. But when Huberta Bloembergen asked her husband when he would give her a pendant made of his laser material, he had to reply: “I work with cyanide.”

I had a chance to greet Nico and Huberta Bloembergen during the coffee break. He recently celebrated his 90^th birthday, and the pair got married 60 years ago.

2010-05 May, 2010-06 June, CLEO/QELS, Lasers, Lasers, CLEO lasers, cleo, cleo10, laser history, laserfest, cleo/qels, optics, quantum electronics

By Patricia Daukantas

As a high-school graduation gift, I got my first “real” camera – a 35-mm single-lens reflex, rather than a fixed-focus Instamatic for snapshots – and began to learn the artistic joys and challenges of manipulating the depth of field. What, in a scene, did I want to focus on? Sometimes I wanted to keep both foreground and background objects sharp and clear, but I couldn’t, especially when the ambient light level forced me to use a large aperture.

Now, researchers based at the University of Toronto (Canada) say that they’ve developed a new type of video camera that will keep high-resolution near- and far-field images in focus simultaneously.

This “Omni-focus Video Camera” is actually an array of color video cameras that are each focused at a different distance. The images from each of these video cameras are fed into a component invented by OSA Fellow – and frequent OPN contributor – Keigo Iizuka. This component, the “Divcam” (for Divergence-ratio Axi-vision Camera), performs real-time mapping of the distances between the pixels and the objects in the scene. Software developed by another Canadian scientist, David Wilkes, selects individual pixels from all the available camera outputs on the basis of the distance information and puts together a single image that is “omni-focused.”

The researchers say that the camera could have many different applications that could use greater depth of field, ranging from TV studio cameras to laparoscopic medical procedures.

The new camera isn’t commercially available yet, but the university recently announced it to the media. According to Iizuka, who is the principal investigator of the project as well as a Toronto engineering professor, the team last week submitted a comprehensive article about the camera to a scientific journal.

In the meantime, here are a couple of illustrations of the technology (photo credits: University of Toronto).

Above: Comparison between the Omni-focus Video Camera (a) and a conventional video camera (b). Note that the fingerprints are recognizable in (a).

Above: The eye of one sewing needle is captured through the eye of a second needle – 1.17 m in front of it.

2010-05 May, Applied optics, Imaging, Photography imaging, video, video camera, applied optics, photography, camera, lenses, divcam, image mapping

By Patricia Daukantas

What do lasers have to do with Robin Hood and the Sheriff of Nottingham? They turn out to have a rather “deep” connection, if you’ll pardon the pun.

The University of Nottingham – yes, that Nottingham – has begun to survey the hundreds of sandstone caves under the English city with laser-scanning equipment. One of those caves is believed to be the dungeon in which the Sheriff of Nottingham imprisoned Robin Hood (if, of course, you believe that the do-gooding outlaw actually existed in medieval times).

The British Geological Survey mapped the caves in the 1980s, but Nottingham officials would like to use the laser-scanning data to create virtual representations of the caves to increase their tourist potential. In other words, visitors would be able to explore the caves without experiencing the associated “health and safety issues,” as the BBC report put it.

The Nottingham Caves Survey has its own website at which it explains the laser scanning procedure.

We’re all about to be inundated with everything “Robin Hood,” as the Ridley Scott movie by that name is readied for a debut next week. In this month of the laser’s 50^th anniversary, it’s interesting to contemplate the intersection of modern optical history with the legends of yore.

2010-05 May, Applied optics, Miscellaneous Optics, Optics and pop culture lasers, laser scanning, nottingham, robin hood, mapping, optical history