My hotel’s wireless internet completely crapped out late Sunday night, and they still have not been able to get it fixed. Fortunately, there’s wireless connectivity in some of the conference center, so I thought I’d post an update while I’m thinking of it. Being the first ‘real’ day of the conference, there were a lot of distinguished speakers.
Monday was the plenary session, where all the awards are given, as well as plenary talks. I didn’t stay for the entire session (way, way too many awards), but I stuck around for the Frederic Ives Medal/ Quinn Endowment, whose description is
Recognizing overall distinction in optics, the Frederic Ives Medal is the highest award of the Society. It was endowed in 1928 by Herbert E. Ives, a distinguished charter member and OSA President, 1924 and 1925, to honor his father who was noted as the inventor of modern photoengraving and for his pioneering contributions to color photography, three-color process printing, and other branches of applied optics.
This year’s award went to Professor Sir Peter Knight, a well-known researcher in the field of quantum optics. He presented a talk on “Light, Photons and Nonclassicality” which was quite nice. In essence, the talk focused on Knight’s researches into understanding wave-particle duality of photons. For instance, we know that light produces interference patterns in single slit or Young’s double slit experiments; such interference patterns remain, however, even if only a single photon is passed through the system! There are many questions which remain concerning where the ‘barrier’ lies between ‘classical’ optics effects and ‘quantum’ optics effects; Knight’s talk focused largely on the argument that everything is ‘non-classical’, if one looks hard enough.
He also produced a delightfully horrible physics joke, in pointing out that Shakespeare obviously knew quantum optics: “Is this a† I see before me?”
This year is the 50th anniversary of the discovery of the laser, or perhaps more accurately, the 50th anniversary since the publication of the first laser paper by Arthur Leonard Schawlow and Charles Hard Townes. The FiO meeting held a special symposium on the birth of the laser, and the session was started off by Townes himself giving his personal reminisces. Apparently he has essentially given this talk many times before, but I hadn’t heard it and enjoyed it immensely.
Townes suggested that his work illustrated the importance of three ideas: basic research, interaction between research fields, and interaction between individuals. Townes’ work incorporated all three, and it’s nice to hear someone who developed such an important, practical device emphasize these points. Townes himself was motivated by his investigations into microwave spectroscopy, and his desire to push these spectroscopic investigations into visible wavelengths.
It is interesting how many people told Townes his work was simply not possible, including two department chairs and Nobel prize winners: I.I. Rabi and P. Kusch. In a chance meeting on the street, Townes encountered N. Bohr and explained his idea, and was also flatly told that it couldn’t be done. The funniest description was of a meeting at a party with J. von Neumann, who at first also flatly stated that the idea was not possible. After a cocktail, though, he came back very excited and said, “Hey, I think you’re right!” Even the patent lawyers didn’t want to waste time on a patent for a device which could be used for optical communications, because Alexander Graham Bell had tried to communicate with light and hadn’t gotten it to work!
It was also interesting to hear that Townes managed to derive and solve the equations for laser operation after conversations with a biologist in Tokyo who was studying the “statistics of populations in microorganisms.” Townes concluded with an observation that, before the laser, people were under the impression that optics was all “known” and that there was little new to be done. Since the laser’s invention, there have been 8 Nobel prizes awarded for work directly related to the laser.
I attended one major technical session during the day: a session on “transformation optics and metamaterials”, which includes work on so-called “optical cloaks” that we’ve discussed on this blog before. “Transformation optics” refers to mathematically deriving new devices by ‘bending’ light in the desired manner and then backtracking to determine what sort of device can accomplish this task.
The first talk, “Quasiconformal mapping in cloaking – invisibility carpet,” was by J. Li, X. Zhang, and J.B. Pendry, the latter of whom is one of cloaking’s “founding fathers”. In essence, they mathematically transformed their original, spherical, cloak into a flat “carpet” under which objects could be hidden. Light reflecting off a carpeted object on a flat surface would be reflected as if only the flat surface were present. The advantage of this carpet is that it requires less variations in refractive index in its design, and could in principle be constructed from silicon which has been appropriately perforated with air-filled holes.
The second talk, “Ray optics at subwavelength scale,” by S. Han et al., looked at mathematical techniques to use geometrical optics to study and design subwavelength-scale devices. I didn’t really understand the method at first glance, but one of the applications of their technique was interesting: they designed a ‘flat-to-flat’ meta lens which can blow up subwavelength features into a macroscopic image. If accurate, this is a really neat application: optical imaging is traditionally limited to a resolution of about a half-wavelength. This ‘meta lens’ could in principle allow imaging of smaller features without a complicated apparatus.
The third talk, “Transformation optics with metamaterials: a new paradigm for the science of light,” by U. Chettliar, focused on the production of magnetic properties at optical frequencies. In principle, when light interacts with matter, the matter can have both an electric and magnetic response. At optical frequencies, however, most natural materials have a negligible magnetic response. However, to make interesting metamaterials, the magnetic response is essential. One must engineer new materials to produce magnetic behavior.
It is possible to construct metal nanorods (rods with a diameter of rougly a billionth of a meter), and a pair of these rods closely spaced can have a significant magnetic response. A large collection of nanorods will produce a macroscopic magnetic response. Materials of different colors were produced where the colors were determined entirely by magnetic properties.
Such nanorods can also produce an anisotropic electrical response, which is the fundamental ingredient in optical cloaks. The authors describe the construction of an optical cloak using radially-oriented wires, sort of a nano-brush! A pseudo-broadband cloak may also be possible, though the method of making it was a little unclear.
That’s all that I’ll say about Monday’s sessions; more to come later!