Musings on optics, physics, astronomy, technology and life

Posts tagged ‘optical communications’

Could your light bulb talk to you? (Update on Li-Fi)

A “talking light bulb” isn’t the product of some tin-hatted paranoiac — not if the light bulb in question is an LED model, and not if you’re using a Li-Fi signal in place of Wi-Fi.

What is Li-Fi, you may ask? Basically, it’s a type of optical wireless communications (OWC) in which a LED, not a radio-frequency router, gives off the signal that talks to your device. I wrote about it in this 2014 article for Optics & Photonics News. If you’d rather get your information by listening to it, researcher Harald Haas, who coined the term “Li-Fi,” gave a TED talk and demonstration about it in 2011.

Although that speech is four years old now, Li-Fi hasn’t made much of a dent in the marketplace … yet. Every wirelessly connected device you already own — smartphone, tablet, laptop, Fitbit, whatever — would need to have a second set of receivers and transmitters to communicate with Li-Fi as well as Wi-Fi “hot spots.” Still, it’s hard to imagine how the so-called “Internet of Things” will develop if we don’t increase the amount of electromagnetic bandwidth we use for communications — and Li-Fi would open up a lot of bandwidth for sure. Perhaps, in the not-so-distant future, flight attendants will hand out Li-Fi converters to airline passengers so that they can use their devices to communicate while traveling, the way they now hand out headphones (or used to hand out headphones, depending on your flight) and beverages.

Recently, Haas’ group, based out of the University of Edinburgh in Scotland, has figured out how to make organic solar cells into Li-Fi receivers as well as power sources. That’s cool, because in our quest to endlessly miniaturize our devices, we don’t leave a lot of real estate open for transmitters and receivers — or for additional battery packs, for that matter. If you’re truly interested in the technical details, you can find the original article here.

A slightly different, more marketing-oriented twist on Li-Fi technology is offered by a Boston-based company called ByteLight, which was recently acquired by another company called Acuity Brands. We shall see how that shakes out and how OWC will evolve over the next few years.

(P.S. Please, can we come up with a better phrase than “Internet of Things”? That sounds way too much like the “information superhighway” you might have heard about back in 1990 or thereabouts.)



A very scientific Thanksgiving

I hope all my U.S. readers had an excellent Thanksgiving yesterday, and I hope you all have an excellent weekend, whether you are getting an adrenaline rush out of the Black Friday sales or you are trying to dodge commercialism altogether.

This year we got a reminder that the eye surgery known as LASIK descended from some experiments on Thanksgiving turkey leftovers. I already knew about this, of course, but it’s great to hear that the tale will be going into the OSA Centennial History Book so that future generations will know the origins of this procedure, which has enormously benefited some of my highly nearsighted friends.

Yesterday afternoon, part of Greenbelt, Maryland, was hopping as Comet ISON passed close to the Sun. NASA hosted a Google+ hangout from Goddard Space Flight Center, just a couple of miles from my computer desk, and I was watching along and retweeting things on Twitter. At the time it really looked as if the comet had vaporized entirely when it grazed our local friendly star, but perhaps part of it survived the close passage. I guess that makes ISON a “zombie” comet! Hey, zombies are extremely popular these days.

This year, for my Thanksgiving dinner with friends, I made my from-scratch creamed corn with cornstarch instead of wheat flour, because a couple of the folks at the dinner table are gluten-intolerant. And I hurried home to do a Skype interview with a researcher in Australia. Yes, we used today’s optical communications technology to talk about tomorrow’s optical communications technology. We live in fascinating times indeed.

“Daddy almost broke the space telescope…”

I already retweeted the link I’m going to write about, but some stories are just so good that they deserve more than a tweet.

The website gave a great review of the new first-person Esquire story of how astronaut Mike Massimino “almost broke” the Hubble Space Telescope during the final repair mission to that spacecraft in 2009. I’ve been fascinated with Hubble for most of my adult life, and I wrote an article previewing the final repair mission in 2008 (just before the mission was postponed for a few months — doggone it!). In fact, when I was at NASA Goddard Space Flight Center for “media preview day,” the four spacewalking astronauts went into the giant clean room to practice handling the actual tools that they would be using in space. I didn’t get to meet them, but from the observation window I could see them walking around in their masks, booties and garb. Needless to say, I thought that was extremely cool!

You can read the full Esquire story at this link.

Massimino, of course, has been a media-savvy astronaut for a long time; I think he was the first astronaut to use Twitter. And he played a bit role as himself in a few hilarious episodes of the sitcom The Big Bang Theory (well, aren’t all the episodes hilarious?).

Speaking of space, NASA is going to shoot for the Moon again tonight, albeit with a small, unpiloted spacecraft. Go here or here or here to find out if you will be able to glimpse the launch, which is going up from southern Virginia instead of Florida. My neighborhood is full of tall, mature trees, but if I walk up the street a half-block or so I might just be able to glimpse enough of the southeastern sky to see something. We shall see.

Most of the publicity surrounding this spacecraft has focused on its planned atmospheric and dust experiments, but the Office of Science and Technology Policy informs us that the craft will also test out a new kind of laser communications system that could potentially rocket-propel (metaphorically speaking, of course) the bandwidth from space.

Clear skies!

First woman to the Moon!

Did you think that the last person we sent to the Moon was 40 years ago last month? Well, think again!

OK … not quite in corporeal form. More like “telepresence.” But at least this person was a woman! In fact, she’s probably the most famous woman on the planet (ahead of  Queen Elizabeth II, Hillary Clinton, or even Oprah).

Let me explain. NASA has a spacecraft called the Lunar Reconnaissance Orbiter (LRO), which was developed at Goddard Space Flight Center, just a couple of miles down the road from where I sit. I’m pretty sure the LRO craft was still at Goddard when I toured the place in the summer of 2008 in preparation for my OPN feature article, “Hubble’s Final Servicing Mission.” Launched in 2009, LRO is polar-orbiting the Moon and mapping its surface in three dimensions.

In fact, LRO already has a laser link with NASA Goddard, which uses the laser pulses to figure out the precise position of the spacecraft with respect to the Moon. So all the researchers had to do to “send” this famous woman — the Mona Lisa — into space was to encode a black-and-white image of her into the laser signal that was already heading out to the LRO, and then verify that it had been received properly.

This was the first time humans have conducted one-way laser communications at planetary distances, according to the principal investigator of the laser altimeter aboard LRO.

As usual, NBC News science editor Alan Boyle wrote a fine article about the experiment. The original experiment was published in Optics Express (disclaimer: I still write for another OSA publication as a freelancer).

The “demise” of scientific journals

I’m sitting here, working on a feature article that required me to do a lot of research in scientific journals going way-back-when. And I notice that one of the articles I’m citing, from an issue of Nature back in December 1970, is followed on the same page by another essay titled “Demise of Scientific Journals.”

Now, I don’t have the full journal-related essay, because I didn’t think to download the whole thing while I was at the library, and my in-home access to Nature doesn’t let me go back that far. Still, I am intrigued.

The “Demise” article is not credited to an author by name, just to “our Washington Correspondent.” He (I’m assuming the correspondent was a “he” — this was in 1970, after all) quotes a then-recent study by the U.S. National Academy of Sciences. The NAS committee predicted that “journals will eventually be rendered obsolete by the computer console, although it may take ten years before each major research centre in the United States possesses a suitable terminal, a further decade for small groups of scientists to come to own consoles and yet another ten years to provide links with other continents.”

Hmm, let’s think about that. This article was written about 18 months after humans first landed on the Moon. I’m sure that people back then were still making pretty optimistic projections about Moon bases and Mars expeditions.

Ten years after the NAS committee … that would be 1980, and mainframe terminals (think VAX) were in colleges and universities, I’m sure. However, students still typed up their term papers on typewriters and went to the library to make photocopies of journal articles.

Ten years after that … takes us to 1990, and scientists certainly had their own personal computers on their desks at work, and probably at home too. Or they might have had Sun Microsystems workstations that were networked together. There was even a way to send “electronic mail” or “e-mail” messages to colleagues at other institutions, although the protocols for getting messages from one computer network to another could be cumbersome. (Quite a few pages in the 1993 membership directory of the American Astronomical Society were devoted to translating addresses to and from ARPAnet, Bitnet, JANET, NSFnet, SSL, etc.)

Ten years after that … by 2000, communications “with other continents” was definitely old hat!

And scientific journals still exist. I think there are more of them than ever before. If you’re already a journal publisher, it’s easy to start a “virtual journal” that’s online-only and/or aggregates articles from related journals in the field. Scientists all over the world are publishing up a storm, and the “information superhighway” gets bigger every year.

So … Nature‘s prediction turned out to be way too conservative. However, while we were advancing the computing and communications technologies much faster than anticipated, we didn’t get around to building those Moon bases and exploring Mars. What happened there?

Crime-fighting glove, deaths of Nobel laureates, and other science news

Seen on CNN by way of Popular Science:  a crime-fighting armored glove equipped with taser, video camera, laser pointer and flashlight. Of course, when I first caught the mention of this glove on the news network, my first thought was about the laser pointer and basic eye safety.

Much has already been written about the potential eyesight hazards from laser pointers — a simple Google search on “laser pointer eye safety” yielded about 312,000 hits. The green laser pointers tend to pose a greater hazard than the red pointers because our eyes are much more sensitive to that 532-nm green light than to red wavelengths. The video clip on CNN definitely showed a green laser beam aimed at the “suspect’s” chest.

You can certainly debate whether this armored glove would be of any use to a SWAT-team member or a regular cop — in fact, there’s already plenty of debate on the page referenced earlier. I would certainly urge the product developers to consider whether the laser is needed at all (tasers don’t need pinpoint accuracy, do they?), and if it is truly necessary, to make sure that all glove wearers undergo proper training with the laser. Green lasers can damage eyesight permanently! And if law-enforcement officers don’t have a lot of sympathy for violent perps, they should at least show concern for innocent bystanders caught up in the crowd situation.

Now, speaking of the video camera included in the glove … no way could such a gizmo fit inside a glove if the team of Willard Boyle and George Smith hadn’t dreamed up the charge-coupled device more than four decades ago. Those little CCD chips changed video cameras from those giant hulking behemoths seen in old footage of NASA launches and political conventions to compact, portable recorders that can go anywhere from the middle of huge protest rallies to the depths of the ocean and the heights of Earth orbit. Oh, yeah, not to mention detectors that take long-exposure astronomical images in a fraction of the time required by photographic plates … and today’s ubiquitous digital cameras.

Boyle died last month at the age of 86, and his death was noticed by the U.S. press as well as in his native Canada. Intriguingly, his obituary in the New York Times was headlined “Father of Digital Eye,” but the first version of the article mentioned  that Boyle developed “a ruby laser,” which left me scratching my head — so then what was that big celebration of Ted Maiman’s work all about, then? Fortunately, the Times corrected the obit to match what the Washington Post got right to start with: Boyle worked on the first continuously operating ruby laser. Maiman’s invention was a pulsed laser, and everyone working in optics knows the difference between pulsed and CW lasers.

Speaking of Nobel laureates and the New York Times, I did a double-take when I saw the obituary headline describing Rosalyn Yalow as a “Nobel Physicist.” Because every female who studies physics knows that there have been only two women so far who have won a Nobel in physics: Marie Curie and Maria Goeppert-Mayer. But, see, I didn’t know until I read her obituary that her academic training actually WAS in physics. Let this be a reminder that physics really is the most fundamental of all the sciences. (And Yalow wasn’t the only physicist to win a Nobel in medicine; for example, Allan Cormack and Godfrey Hounsfield won for developing computer-assisted tomography, or the CT scan, and Haldan Hartline and George Wald won for unlocking the secrets of the visual processes in the human eye — optics!)

News from OPN

The June issue of Optics & Photonics News is now online, so my May feature on Arthur Schawlow has gone behind the OSA members’ firewall. The new open-access feature is on cell identification with 3-D computational holographic micrography. (Try saying that fast three times!) Plus, I’ve got an OPN Newsroom article on a new technique for sending lots more data down a single-mode fiber.

This British royal wedding brought to you by … British technological ideas

I’ll admit it … I’m a bit of an Anglophile. When I was 14 I started saving pennies in an old Band-Aid tin in the hopes of traveling to England someday. I finally got there when I was 29, just before I got my wisdom teeth pulled.

So I’m planning to rise incredibly early tomorrow, for at least long enough to switch on the second-hand VCR (it didn’t come with a remote control, so I can’t program it). But while I watch the magnificent splendor of the wedding of the future king of Great Britain, I will be thinking of the Brits who made it possible for us billions of worldwide viewers to see the ceremony progress in real time.

First of all, as everyone who’s ever cracked open a science-fiction novel knows, Sir Arthur C. Clarke (1917-2008) dreamed up the concept of a geostationary communications satellite in 1945, long before any country on Earth had the ability to launch an “artificial moon.” Though famously a resident of Sri Lanka for more than half of his life, Sir Arthur was born in England and studied mathematics and physics at King’s College London.

Back in the 1960s, Sir Charles Kao, then working at the U.K.’s premier industrial telecommunications laboratory, got

silica fibers courtesy of Wikimedia Commons

silica fibers

the idea for using fiber optics to transmit data. Kao was born in Shanghai, but his family moved to Hong Kong (then British) when he was a teenager, and he earned his Ph.D. at University College London. Kao and his British lab colleagues worked hard to study the structural and material properties of optical fibers, and then Kao became something of a scientific evangelist, advocating for the adoption of single-mode fiber and predicting that the world’s oceans would be crisscrossed by cables five years before the first transatlantic telecom cable was installed. He was one of the recipients of the Nobel Prize in Physics in 2009.

So, whether the images of the lovely Kate and the dashing Prince Wills arrive at your “telly” via satellite or optical cable, you have someone with a British education to thank.

Incidentally, OSA’s first president from outside North America was a Brit — Sir Peter Knight of Imperial College London. Besides Imperial, several U.K. universities have distinguished programs in optics and photonics, including the University of Southampton — and William and Kate’s alma mater, the University of St. Andrews in Scotland.

Image courtesy of Wikimedia Commons.