Category Archives: optics

Vision on

Posted on by

Some eye diseases have a nasty habit of being all but untreatable by the time the patient is aware of the symptoms; a dirty trick on the part of the designer. Age-related macular degeneration is one, but AMD spends a long time brewing in the tissues of the retina before making itself known as actual vision loss. Now it turns out that it might be detectable during that gestation period, through a simple test of how a patient’s eyesight adjusts to darkness. I wrote about that test for Optics.org.

Also in the eyesight department: retinitis pigmentosa is being tackled through electronic implants of two different types, the epiretinal and subretinal varieties. Each sits in a slightly different position in the retina and does its job in slightly different ways; neither is guaranteed to succeed nor to be hassle-free for the patient. Intriguingly, the two approaches ultimately stem from a fairly fundamental difference of opinion about what AMD does to the retina.

Robotic surgical systems are becoming more advanced all the time; the top-of-the-line ones already have a distinct air of science-fiction production design about them. The overlap with the equally rapid advances in biomedical imaging techniques seems obvious, but the synergies are not materializing as fast as you might think. I spoke to Intuitive Surgical to find out why, and what benefits will follow once the two camps get in sync.

And: a report from a conference on biophotonics held at University College, London. Among other things discussed, a potential use of optogenetics for turning epilepsy off in the brain as soon as it starts to manifest itself.

Doctors at large

Posted on by

Two more technology stories left over from my trip to San Francisco:

A team at UCLA have spent the last few years developing microscopes that don’t use lenses to do their magnifying, relying instead on something closer to holography to get the job done. Among other advantages, this allows a functional microscope to be small enough to be slotted onto a modern cell phone and use the phone’s camera to record the images; and that in turn allows meaningful microscopy to potentially be done on a cell phone just about anywhere. This is “telemedicine,” and it could be huge. Case in point: images of malaria-infected red blood cells taken in the field, fed into an online system and presented to volunteer observers around the world for them to visually sift through. The real trick is making people want to get involved in such an exercise, and accommodating the fact that they might not be any good at it. The answer: turn it into a game.

OCT is not recent technology; it’s already ubiquitous for looking at the structure of the retina to a depth of a millimetre or two, among other things. But millimetres was more or less the technique’s limit. Tweaking things so that the same method can image over distances measured in centimetres, taking an image of, say, the entire eye from front to back, is a big step forward. The idea of extending the range even further, over meters of free space, seems almost ridiculous; but that could be on the way too.

Vision things

Posted on by

Two holdovers from my trip to Baltimore for SPIE DSS 2012 have appeared on Optics.org:

Since shining a laser pointer in the general direction of an aircraft pilot seems to be the jape that won’t go away, optical filters that can limit the dazzle are in demand, and the military are just as interested in them as commercial airlines – probably more. Filters usually work by blocking the particular laser wavelengths used in your average pointer, but a better approach might be to block incident light based on its power instead. KiloLambda showed off a wide-band filter that uses a layer of carefully manufactured nanostructures and exploits their non-linear optics to block laser light when it passes a designated power threshold. Below that, the filter stays clear at all wavelengths; above it, transmission is either limited to a certain value or blocked completely.

Nanstructures are also the key to a scintillator material made by the applied research arm of Georgia Tech, a cerium-doped gadolinium halide material cast in a glass that scintillates when hit by incoming gamma-rays. If the nanoparticles used can be held below a certain size, and about 20 nanometers or so seems to do it, then the scattering of the scintillated light which can bedevil any kind of accurate reading is drastically reduced. Plus a glass or glass-ceramic material is much easier to handle than a fragile scintillation crystal. Plenty of room for improvement in the resolution, though.

And away from DSS: further work on retinal implants, a topic that has now entered the watch-lists of TV news producers everywhere. The principle of restoring sight to someone suffering from a condition like age-related macular degeneration hinges on the fact that it’s the photoreceptors in the retina that have died, not the neurons behind them. Implants to take over the job of the receptors and fire the neurons when light hits the retina are well past the status of pipe dreams, but there are a wealth of problems – not least among them, how to power the array of photoreceptors while it goes about its business. A group from Stanford University, applying scrupulous logic, think the answer may be to build an implant which draws its power from the same incoming infra-red light which brings the visual data, and their lab trials suggest that they’re on the right lines. Not quite a solar-powered retinal implant, but not too far off. Not a bionic eye either, although Steve Austin is the gift that keeps on giving for headline writers on a deadline.

Military-industrial complexities

Posted on by

A week in Baltimore at SPIE’s Defense Security and Sensing conference on behalf of Optics.org produced a few published things.

Among them, coverage of an address from Bruce Carlson, director (possibly former, by now) of the National Reconnaissance Office. Viewed by a visiting European, the back-and-forth over funding and priorities within the US intelligence community is endlessly fascinating. But I hadn’t realized that the NRO also tracks orbiting satellites and takes action when there’s an imminent collision among all the circling hardware. A man who can say “Every other week or so I manoeuver a satellite around”, is one with an interesting desk. As you might expect when the holder of this post addresses an open meeting of international delegates, there was a certain amount of frostiness in the air; forty-two minutes in, someone asked a question about the potential usefulness of the NRO’s info to human rights organizations, and Carlson more or less adjourned the meeting on the spot.

Also a keynote from Franca Jones of the White House science policy office, who made the point that there’s room for much more joined-up thinking when it comes to gathering data on climate and habitat, and a clear connection between having that kind of info on hand and the ability to predict things like cholera outbreaks. Biosurveillance still has an almighty image problem though, starting with the word; expect “biosensing” to feature in a larger font.

And a discussion between military strategists and venture capitalists about why the military needs new kinds of infrared sensing technologies. It is still jarring, nearly eleven years after the game most visibly changed, to hear a man from DARPA comment that “our mission is changing, but our sensor technology is not,” although here too you wonder if the discussion would have been quite the same behind closed doors and away from international observers. None the less, the sentiment that changes in warfare can be good for the progress of technology and the balance sheets of private companies is hard to argue with, even while quietly wishing for a different kind of world.

Camera unobscura

Posted on by

A while ago I asked a market analyst if he could identify the magic ingredient that changed camera phones from a niche technology into ubiquitous consumables, assuming he’d say it happened when engineers worked out how to get enough megapixels into the things to make the photographs actually worth looking at.

His answer was Facebook. That and consumer willingness to embrace data plans that let people successfully send pictures without going bankrupt or expiring from boredom while they were about it.

This fact came up while researching an article on camera phone optics for The Optical Society. Another nugget was that one of the foremost developers of a particular technology that seemed tailor-made to suit the camera phone sector, a company I’ve been writing about in one way or another for years, had withdrawn from the fray while I wasn’t looking, brought low by a licensing strategy that looked like exactly the right idea on paper.

Point being: becoming ubiquitous is a bruising business. But it certainly pushes technology forwards.

My feature about some of the optics technology built into camera phones is the cover story of the February issue of the OSA’s Optics and Photonics News, and is also currently an open-access article on their web site.

Ride that switchback

Posted on by

Three months ago the US laser sector was pondering the need to stock up on canned food and shotguns, but the sky remains un-fallen for the only reason that matters: on the whole demand has failed to collapse.

There’s a large pile of caveats. Concentrating on the year-on-year figures helps avoid the headache that reading the sequential numbers causes; heavy industry is still more inclined to put money on the table than the technology sector; exporters will fret that the Eurozone and US economies are heading in different directions again, although probably not as much as Europeans will. But most vendors are still optimistic, the latest stage of the ride that’s as unrelenting for them as it is for the analysts asking about it.

So I asked an analyst about it. The latest of my regular chats with Mark Douglass of Longbow Research about what’s going on is now posted online at Optics.org.

Summer of discontent

Posted on by

So the unalloyed good news didn’t stay pure for long. In April the US optics and laser sector was not only happy to find itself recovering, but daring to use words like “optimistic” and “robust.” Since then: complete mayhem.

I spoke to Mark Douglass of Longbow Research for Optics.org, and discussed why the clouds were gathering in July even before the storm broke in August. This time it includes words like “clear as mud.”

Numbers game

Posted on by

the delicate work of stem cell injection. photo: J. Michael White, Washington University School of Medicine.

One of the more modest notable features of stem cell research is the contrast in numbers. Researchers perform precise and exacting microsurgery on individual cells, prizing minute openings in the membranes of eight-cell embryos so that stem cells can be introduced through the gap. And to prepare, they carry out large-scale housekeeping operations on cultures containing millions of cells, ablating and scoring and where necessary destroying them in bulk. The pattern holds for fertility studies and IVF too.

If the same basic kit could do both kinds of operation, things would not only go faster but be cheaper too. Hamilton Thorne has designed a family of microscope objectives that incorporate miniaturized laser diodes but still fit into standard laboratory kit. Pick the right one, and your microscope has just acquired a laser powerful enough to do the housekeeping or delicate enough to do the prizing.

My chat with the company for Optics.org about the goal of making lab-scale eye-safe lasers a practical proposition for cell biologists, and the small matter of a $1.3 billion market sector to be tapped, is here.

Optics and Photonics News catch-up

Posted on by

Two articles of mine have been in issues of Optics and Photonics News recently:

Sailing in Stormy Seas (April 2011) dug into the vexed question of UK science funding, an area where the Technology Strategy Board is making a valiant effort to square the impossible circle. That currently includes spreading its funds over a number of new innovation centres, one of which might end up being dedicated to photonics.

A Bright Future For Photonics21 (June 2011) assessed the success Europe’s photonics community has achieved by acting in unison for maximum political impact. The Photonics21 group has persuaded the European Commission to designate photonics as a Key Enabling Technology, with consequent opening of doors and federal wallets. Now the companies have to deliver.

Both available in print and online, for now to OSA members.