Reading PDFs on the go with a kindle!

Postings have been a bit slow due to the holidays kicking in! Anyway, I often carry a couple of research papers or books in my backpack and read them on the train and/or buses. My wife found that I carry too much stuff everyday, on my way to work, and decided to offer me an amazon kindle. I must say that it's not only a great gift but also a sound investment. I got rid of my research papers and started uploading the PDFs on my kindle and reading them on the go. As a bonus, I have my time magazines delivered to the device for only $1.49 a month!

Encrypt your data in a shared facility

Whenever you're using a shared facility, you have to realize that everybody has access to your data, including your competitors. It's your duty to protect your data. I often hear students complaining that people viewed their SEM images on a shared PC or that their macro code was *stolen*.

If you have proprietary code that you must use on shared machines or if you have data images which you wouldn't want to see ending up on some other research group's PC, then my advice is to encrypt your data.

A nice encryption software that I use is AxCrypt. I even requested some systems administrators/ dedicated staff to install it on PCs where I've written a lot of proprietary code for running tools or where I have a lot of confidential data.

This advice is relevant especially if you are funded by the Air Force Research Labs, ARO, DARPA or any other defense funding agencies. You do not want your data to be floating around!

Article Highlight: Subwavelength nanoimaging in 3-D

I just stumbled upon an interesting article published in Phys. Rev. Lett. by A. Govyadinov et al., entitled "Phaseless three-dimensional optical nanoimaging". Actually, the preprint is on arxiv.

The authors proposed a method in which the subwavelength details of a 3D structure can be recovered in the far-field. It is a very well-thought method which is based on the solution to the inverse scattering problem for a system consisting of a weakly-scattering dielectric sample and a strongly-scattering nano-particle tip. Interestingly, their nano-scale optical tomography technique relies neither on phase-measurements of the scattered field nor on phase-control of the illuminating field.

On the fundamental flaws of cloaking by metamaterials

Invisibility cloaking, using metamaterials, excites the scientific community, the general public, amateurs of sci-fi and most importantly the funding agencies. If you think about it, it is indeed mind-boggling to be able to realize a Harry Potter type cloak!

The metamaterials community, in particular John Pendry and Ulf Leonhardt have thought and pioneered the first invisibility schemes by using metamaterials. The first demonstration of the invisibility cloak was demonstrated by David Smith's group. And subsequently, several researchers have been actively working (both theoretically and experimentally) on cloaking.

Funding agencies and the general public assume that we're close to cloaking military tanks, fighter airplanes, etc... And accordingly, with this type of technology, we could effortlessly win the war in Afghanistan or any war for that matter!

Well the reality is far from our wild imagination! Cloaking by using metamaterials suffer from two fundamental flaws:

1. We can only cloak objects which are of the same size as the wavelength of light.

For instance a typical human eye will respond to wavelengths from 400nm to 600 nm or so (+/- a few nm of course). It means that if you want to cloak an actual object from humans, it cannot be larger than 600 nm!!! This implies that using metamaterials, we can only cloak nanometer size objects, and if you think about it, these objects are so tiny that they are already cloaked!

2. Metamaterials cloaks are extremely sensitive to loss.

In theory, we can design lossless materials where the cloak works out of the box. But in the real world, we have to use materials which are lossy (suffer from energy dissipation). Thus, realistic materials will kill the cloak! However, in the future, we will be in a position to develop robust gain compensation schemes to compensate for losses.

2009 MRS Fall Meeting (Metamaterials Session)

The Metamaterials session of the 2009 MRS Fall Meeting started today, at the Hynes Convention center, in Boston.

Good opening talk by Martin Wegener, who talked about his Gold Helix Metamaterial, and showed impressive ray tracing images of the carpet cloak. Like me, he's a fan of 3D ray tracing.

Overall, it was a very productive day. I also gave a talk entitled "Superresolution Imaging Using Bulk Nanowires Metamaterials at Optical Frequencies" in lieu of my colleague who couldn't present his own talk on transformation optics since he was sick.

I presented the first demonstration of the reconstruction of subwavelength features of an object, over a record distance of more than 6 times the wavelength by a nanolens made up of bulk metamaterials of nanowires, and with a resolution of at least wavelength/4. This is considered a significant breakthrough and was well received by the metamaterials community. We recently submitted the paper and are impatiently awaiting its publication. We strongly believe that this piece of work will get extensive media coverage.

Kudos to the session organizers/chairs Nader Engheta and Minas Tanielian.