DOI: 10.1097/OPX.0b013e31804bbd2f

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Issn Print: 1040-5488

Publication Date: 2007/03/01


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Optics in Research Renaissance: But Now Making Objects Invisible?

Anthony J. Adams

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Optics has been fundamental to the development of optometry; no other health profession has optics so firmly at the center of its heritage. But two thirds of the way through the last century it appeared to be a stagnant topic in our educational training programs and some feared it was becoming a forgotten topic—less ‘glamorous’ than the exciting biological advances in eye and vision care and less central to a profession that was embracing its role as the primary eye care practitioner.
But the emergence of new methods of not only measuring optical aberrations (wave front optics) beyond sphere and cylinder, but also the application of adaptive optics to correct the aberrations, opened up astounding advances for eye and vision health care. And optometry schools and their faculty researchers around the world are leading the way in applying both adaptive optics and wavefront technology. In a recent editorial1 I noted this and pointed to a new and exciting era in optometry for optics—“the new visual optics.” The applications have already entered practice in refractive surgery, contact lens design, and even spectacle prescriptions. And some of the more remarkable applications are in imaging instrumentation for optometry and ophthalmology. With the correction of a patient’s individual aberrations we can see blood vessels three times smaller than we routinely see today. And we can see individual photoreceptors and the flow of blood cells through retinal vessels. Our imaging of in vivo retinas will be enhanced impressively over the already superb slices of retina we see today with optical coherence tomography (OCT). See Fig. 1, provided by Donald Miller of Indiana University.
But now we face what most of us call impossible concepts about light and its refraction—at least impossible if we look at our training in the last 100 years. So what is “negative refraction,” and how can light actually be slowed down to the speed of a cyclist, and what of the new properties it has at that speed? Can light be made to render objects invisible? Sounds like unbelievable magic! Yet just a couple of weeks ago science writers in Nature reported on such concepts and alerted us to upcoming publications. In our April issue of Optometry & Vision Science “News” I will quote the full Nature News report but suffice it to say here that serious scientists are serious about all of this. Until 2003 many scientists fiercely denied the concept of “negative refraction,” involving light bending in the opposite direction to the way we learned; some still dispute it. In 2003 “negative refraction” was demonstrated first with microwaves,2,3 then with infrared radiation.4 And only this year claims are made for demonstrating the same properties for light waves, as Katharine Sanderson reports for Nature.5
Now Jennifer Dionne and Henri Lezec, working in Harry Atwater’s group at the California Institute of Technology in Pasadena, have unveiled a material that they say has a negative refractive index for visible light. Dionne presented the results on 11 January at Nanometa 2007, a conference on nanophotonics and metamaterials held in Seefeld, Austria, and the group has submitted them for publication.
Fig. 2 is a startling rendition of the impact of “negative refraction” envisioned by in the Nature article. While most of us will find this all to difficult to imagine, and there is considerable argument about what the practical applications might be, there is little doubt that we are facing yet a new era of excitement in optics.
Look for a more complete accounting in the April Optometry & Vision Science “News” section.
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