optics.org blog
July 7, 2008
Laser searches for signs of life
Could an optical technique used every day in laboratories all over the world help to answer the fundamental question of are we alone in the Universe? A team of scientists from the US and the UK certainly hopes so. The group believes that its laser fluorescence equipment can be made to withstand the harsh environment on Mars to search for life on the planet.
The researchers propose that the system could operate on any Mars lander or rover and be made ready for launch in just five years. The key challenge they face is to make the instrument light enough to be flown, and resilient enough to survive the cold, -120°C Martian nights.
Michael Storrie-Lombardi and Jan-Peter Muller, of the Mullard Space Sciences Laboratory in the UK are carrying out experiments both in the laboratory and at Silver Lake in California, US - a well-known Mars analogue study site. "Being able to test the fluorescence signal both under laboratory conditions and in the field has been critical in ensuring the system will work on the surface of Mars," said Muller.
The approach uses ultraviolet fluorescence to illuminate soil and rock in search of tell-tale signs of life. In particular the group is searching for chemical compounds called polycyclic aromatic hydrocarbons (PAHs), which are believed to be one of the earliest forms of organic matter in the Universe. And, just like living organisms, PAHs fluoresce when excited by ultraviolet light.
"While using fluorescence to illuminate organic material has been carried out for decades, light sources were too large and unwieldy to use for a robotic mission to another planet," said Storrie-Lombardi. "However, new generations of LEDs, which are very small, reliable and energy efficient make this possible."
"Placed on a Mars rover, one of these LEDs positioned a few centimetres from a target can easily provide enough light to produce fluorescence in small PAHs," Storrie-Lombardi added. "But even more encouraging is the very recent development of a small 375 nm laser diode that can illuminate geological layers and crevices high up on otherwise inaccessible rock outcrops."
The tool is ideal for initial surveys as it requires no sample preparation, does not destroy sample material and requires only electrical power to operate, conserving precious water and other consumable resources for sister instruments.
If you want to find out more about this work, the team has just published a paper in the journal Geophysical Research Letters.
July 3, 2008
Snake eyes
A robot snake that can slide around narrow and intricate pipes checking for leaks along the way may sound far-fetched, but that's exactly what scientists in Norway are working on.
Cybernetic experts are joining forces with optical scientists at SINTEF to develop an inspection robot that will be able to move in pipes of various diameters, right down to 20 cm.
The group is building on the experience and knowledge acquired with previous snake robots called Anna Konda and AiKo. Now, it is developing an intelligent pipe inspection robot on wheels that will be able to climb, navigate intersections and at any given time know its location in the pipe system.
"We want to develop a robot with 10 or 11 joint modules, each with an identical pair of wheels cast in plastic," said Jens Thielemann, from the Optical Measurements and Data Analysis department at SINTEF. "The robot will function as a train when operating horizontally. Such robots already exist, but we want to develop a robot that can climb too."
A time-of-flight camera will provide the robot's vision, allowing it to navigate and move forward on its own. "The robot knows when a left or right turn is approaching and also contains a built-in path description detailing what tasks it should carry out in different situations," added Thielemann.
When the robot enters a vertical pipe, it will lift its head to meet the wall. It can then either move sideways with its abdomen against the pipe and twist itself upwards or it can topple backwards, attach itself to the pipe wall and roll upwards.
The scientists emphasise that the project is at the design stage but hope to demonstrate a prototype model by the end of the year. The final version of the robot will be constructed of aluminium and measure 1.5 m in length.
July 2, 2008
How efficient is your TV?
At first I wasn't sure how Sony could claim an energy efficiency of 232% for its new Bravia JE1 series of LCD televisions, but the answer was in the small print.
Under Japanese regulations, the standard reference point for the power consumption of a 32-inch LCD screen is 200 kWh per year, designated as 100%. Lower consumption is expressed as a higher percentage compared to the benchmark. Anything above a 164% rating is entitled to receive a five-star Energy Saving label.
By that measure Sony's existing Bravia KDL-32J1 series comes in at 173% energy efficiency, with an annual power consumption of 115 kWh per year.
The new JE1 screens go further, hitting an efficiency of 232% for the KDL-32JE1, said to be the highest on the market for a 32-inch screen, while also reducing the momentary power consumption to 89 W.
According to Sony, the secret lies in the use of high-efficiency fluorescent tubes, capable of delivering higher luminance efficiency at lower electric voltage, along with specialized optical film that possesses a higher light transmission rate.
With the KDL-32JE1, Sony has also started to recycle the waste material generated during the production of the optical film used in its LCD TVs, claiming that doing so will effectively reduce the CO2 emissions from its production process by an impressive 40%.
Sony already practices in-house recycling to produce flame-retardant polystyrene for its Bravia sets, and some of that apparently recycles plastics from CRT TVs. As shipments of LCD TVs overtook CRT for the first time last year, this seems only right and proper, evolution in action.
June 20, 2008
Driven to distraction
Adding to the list of in-car gadgets that take our concentration off driving, comes news of a multi-touch interface designed to provide drivers with a futuristic digital dashboard. The Digital Dash Reconfigurable Tactile Display (RTD) is said to be the world's first multi-touch interface that incorporates physical controls with a curved display surface.
The system uses a rear projector unit designed by Osram Opto Semiconductors to display images such as audio controls and maps of other indicators, including images that interface with knobs, buttons and faders, on a display/control surface. A CMOS camera detects touch contact, knob rotations and button movement at the display, which eliminates the need for wires and electrical components. The RTD could be used to control functions such as heating, air-conditioning and rear parking cameras.
The visible projected image in the Digital Dash RTD is powered by Osram's Ostar-Projection LED light sources. In addition, Osram's IR Dragon IR emitter floods the display area with IR light, allowing the CMOS camera to sense the position of the controls or the user's touch on the screen.
According to Osram, the display is well-suited for use in automobiles, sound-mixing boards, video editing, industrial, military and home control use and any other control- and image-intensive user interface applications.
"The touch screen market understands the benefits of RTD technology and we are working to bring this next generation of innovation to the market through the advancements in high power and efficient visible and infrared solid state light sources," commented Tom Shottes, president and CEO of Osram Opto Semiconductors. "With Digital Dash's technology, the futuristic screen designs we see in forward-thinking concept displays can now be a reality."
As we may one day find ourselves happily jabbing at images on our dashboard to adjust the radio, air conditioning and navigation system, I can't help but wonder if we will need another gadget to drive the car.
June 17, 2008
Optics on the brain
Here at optics.org, we always try our best to get extra information from researchers or companies involved in pioneering work. So when I received a press release entitled "Northrop Grumman-led team awarded contract to develop electronic binoculars that use brain activity to detect threats", my first instinct was to find out what new optical innovations were being proposed.
This didn't exactly turn out according to plan, which happens more often than not when we try to report on work from the defence sector. Here's what I can tell you.
An academic and industrial consortium led by Northrop Grumman Corporation has been awarded a 12-month, $6.7 million, phase one research contract to develop a panoramic day/night optical system that will use human brain activity to detect, analyze and alert foot-soldiers to possible threats. The award is part of DARPA's Cognitive Technology Threat Warning System programme, or CT2WS.
Once successfully developed, the claim is that the intelligent neuro-optical system will provide the wearer with an "unprecedented capability to detect targets of interest at an extremely long range over a wide field of view".
During phase one of the programme, the Northrop Grumman team plans to build a breadboard system and complete a preliminary design for the company's Human-aided Optical Recognition/Notification of Elusive Threats (HORNET) system.
HORNET will use a custom helmet equipped with electro-encephalogram electrodes placed on the scalp to record the user's continuous electrical brain activity. The operator's neural responses to the presence or absence of potential threats will train the system's algorithms.
DARPA has the option to extend the contract for two additional phases to develop the subsystems and final handheld assemblies.
Unfortunately, when I tried to find out what new optics will be developed and how the optics and the wearer's brain activity will be integrated, Northrop Grumman was unable to answer. All I was able to find out is that the system will "operate over a range of 10 km, a field of view of 120 degrees and detect people and vehicles".
Integrating your thoughts with an optical system sounds like an incredibly futuristic idea to me. But watch this space, we'll bring you more information when we can.
June 11, 2008
Walk the line
Do you have a unique way of walking? Researchers at the S.J College of Engineering in India seem to think so. They believe that we all have our own individual gait that makes us easily recognizable. The group is so convinced by this idea that it has developed a gait recognition system, which it believes could improve security surveillance at airports, military institutions and banks.
The technique uses a camera to capture a key set of frames over a person's complete walk cycle. The sequence could then be compared with a database by airport security to recognize suspects before they even enter the airport concourse. Comparing such data with CCTV footage may also help to track suspect terrorists or criminals who may otherwise be disguising their features or carrying forged documents.
The researchers emphasize that gait recognition has significant advantages over more well-known biometrics, such as fingerprinting and iris scanning in that it is entirely unobtrusive and could be used to identify an individual from a considerable distance. "The ability to identify a possible threat from a distance gives personnel a longer time frame in which to react before a possible suspect becomes a real danger," the researchers say.
The approach works by capturing side view images of a person as they walk. The images are converted into silhouette form and analyzed, together with height measurements and the periodicity of the gait to classify the walk.
So far, the team has carried out initial tests on 20 people walking in a straight line at normal speed and stride, back and forth in front of a video camera. The researchers found that recognition performance of the system was sensitive to changes in viewing angle above ten degrees but was reasonably robust even when the individuals changed walking speed.
June 9, 2008
A new dimension to computers
The shape of things to come in the computer world will be anything but flat, predicts Roel Vertegaal, a professor from Queen's University, Canada. Thanks to Vertegaal's work on flexible displays at the university's Human Media Laboratory, we could one day see computers integrated into almost any object.
"We want to reduce the computer's stranglehold on cognitive processing by imbedding it and making it work more like the natural environment," said Vertegaal. "It is too much of a technological device now, and we haven't had the means to truly integrate a high-resolution display into artefacts that are curved, flexible and textile, like your coffee mug."
Current work includes developing computers that can take the form of foldable paper allowing users to navigate a document by turning the pages. The group is also developing an interactive computer on a Coke can, which can display video on its surface and respond to touch.
Recent advances in computer technology have allowed inventors to move beyond the rigid, rectangular design of current devices. Developments in touch input technologies now allow for any surface to sense two-handed, multi-finger touch. Advances in flexible displays that use OLEDs to form electronic paper or E-Ink means that displays can be rolled up and put inside a pocket, like regular paper.
Another development, known as Kinetic Organic Interfaces enables computers to adjust their shape according to some computational outcome or through interactions with users. Vertegaal hopes that this will yield 'Claytronic' 3D displays capable of showing pictures as well as physical shapes in 3D.
So perhaps one day we will look back on a time when we used to flick through an ordinary newspaper while sipping coffee from a mug - that is just a mug - and wonder how we ever managed?
May 19, 2008
Reach for the stars
It's not everyday that you can apply to be an astronaut but today is that day. The European Space Agency (ESA) has posted many people's "dream job" advert and is looking to appoint four individuals to its European Astronaut Corps. There has not been a selection campaign since 1992, so this is a rare opportunity to be part of future missions to the International Space Station, the Moon and beyond.
Prospective candidates can now carry out the first step of the application procedure by filling in details online. The deadline for applications is 16 June 2008.
All shortlisted candidates will go through a series of selection procedures and at the end of the day, four lucky individuals will begin basic training at the European Astronaut Centre in Cologne, Germany. The final appointments will be officially announced in 2009.
So, what qualities is ESA looking for? Well, optical scientists will certainly be in with a chance. "The ideal candidates should be competent in relevant scientific disciplines, such as life sciences, physics, chemistry and medicine and/or be an engineer or experimental test pilot," says ESA.
And if you have ever suffered in a lab trying to make your experiment work, you will certainly relate to some of these additional qualities. "Applicants should also have demonstrated outstanding abilities in research, applications or the educational field, preferably including operational skills. A good memory and reasoning ability, concentration, aptitude for spatial orientation and manual dexterity are also prerequisites."
Applicants have to be fluent in English (with Russian being an asset) and should have high motivation, flexibility, team competence, empathy with others and emotional stability.
Right, I'm off to apply and search for a book on "Beginners Russian for Prospective Astronauts".
May 16, 2008
Laser day
On May 16th 1960, Theodore Maiman changed the world when he demonstrated the world's first working laser. He made his breakthrough at Hughes Aircraft Corporation, by generating pulses of coherent light from a fingertip-sized lump of ruby illuminated by a flash lamp. The exact attribution of the invention has historically been a little problematic. Maiman beat a number of other physicists to the post, including Charles Townes who had earlier developed the maser, a microwave forerunner of the laser, while Townes' student Gordon Gould coined the actual word "laser".
How ever the credit should be apportioned, the results have been extraordinary, with lasers playing a huge role in our lives already and further breakthroughs nearly every day. You can be sure that the achievements of laser developers in the next 48 years will be every bit as remarkable as Maiman's ground-breaking experiment. And that optics.org will bring them to you.
May 10, 2008
Photonic crystal fibres set new benchmarks
I wasn't at CLEO for the last day, but optics.org publisher Claire Bedrock was. There was one particular talk that caught her eye:
"For those who stayed for the final day of the conference there was a fascinating day-long symposium on hollow-core photonic crystal fibre. The final talk of the day created a particular buzz, when Brian Mangan of Crystal Fibre of Denmark presented some new results obtained in a collaboration with the Technical University of Denmark.
First up was a fibre with an antiresonant core, which achieved an attenuation of 9.3 dB/km ‐ a new record for this type of seven-cell fibre). Then Mangan presented results for two high-birefringence fibres, one with an air-fill factor of 91% and the other with a lower air-fill factor of 85%. The latter produced an impressive attenuation of 19 dB/km.
When questioned at the end about the future of photonic crystal fibre. Mangan replied that 'there are loads of talented guys in the field and I'm sure we'll find a solution to the limitations'. This seemed an appropriate note on which to end not only a fascinating symposium but an exciting conference."
May 9, 2008
Large-area fibre targets high-power applications
In Thursday's post-deadline session, Liang Dong of fibre laser specialist IMRA showcased a new class of fibre that supports singlemode operation for fiber laser applications requiring high peak powers. According to Dong, the new all-glass fibre will extend the reach of practical ultrafast amplifiers to millijoule pulse energies, and could also lead to continuous-wave fibre lasers and amplifiers in the 10 kW range.
Dong explained that high peak powers requires singlemode operation to be achieved in a fibre with a large effective area. He pointed out that today's large-mode area fibres are limited to a core diameter of 30 µm, while photonic crystal fibres have been demonstrated with diameters of up to 100 µm.
Those figures make it even more impressive that IMRA has achieved singlemode operation in fibres with core diameters of up to 170 µm. The fibres exploit the company's "leakage channel fibre" (LCF) design, in which the core of the fibre is formed by six low-index features arranged in a hexagonal grid. Unlike photonic crystal fibre, in LCF the air holes are filled with flourine-doped silica glass, and so it can be cleaved, spliced and handled in the same way as normal optical fibre.
Versions of the fibre with core diameters of 100 µm and 170 µm were designed as passive LCFs. The 100 µm version achieves a pump absorption of more than 25 dB/m &ndash which Dong says would mean that a typical amplifier could be just tens of centimetres long – while LCFs with larger diameters could yield even shorter amplifiers.
A ytterbium-doped LCF was also fabricated with a core diameter of 50 µm. A single-stage amplifier constructed from this fibre achieved pulse energies of 600 µJ for a pulse length of 600 ps and a repetition rate of 25 kHz, which Dong says shows that "the design is a practical choice for extending the peak power in fibre lasers".
May 8, 2008
OSA launches PhotonXpo for 2009
Keen-eyed delegates may have been intrigued by the signage for PhotonXpo scattered around the CLEO exhibit hall.
Well, all was revealed this morning: it's part of a rebranding exercise for the CLEO technical exhibit. "The goal is to provide the exhibit with its own identity," Colleen Morrison, the OSA's director for for public relations, told me today. "It has continued to expand, and we wanted a name that would better reflect what's out there on the show floor."
This year's CLEO attracted 320 exhibitors, but the organizers hope that renaming the event will increase numbers at the 2009 event in Baltimore, Maryland.
And that's it from me for now. I'm off to the airport for the red-eye flight to London, but look out in the next couple of days for a couple of post-deadline posts.