(Optical) wonders never cease
The optical phenomena that typically provide fodder for the pages of Laser Focus World are based on natural properties often observable in the everyday world-but as science evolves to allow us to work at an increasingly smaller scale, the rules may change.
The optical phenomena that typically provide fodder for the pages of Laser Focus World are based on natural properties often observable in the everyday world-but as science evolves to allow us to work at an increasingly smaller scale, the rules may change. An emerging family of artificial “metamaterials” promises a range of weird optical properties well beyond anything available in nature. Arrays of paired parallel gold rods, for instance, were used at Purdue University to demonstrate a negative refractive index at 1.5 µm. An attraction of negative-index optics is the potential for “superlenses” with resolution finer than the diffraction limit . . . but other strange properties are also a possibility, including invisibility and cloaking (see p. 71).
Improving resolution is a never-ending goal in optics and optical applications. In one example that combines nanoscale microscopy with spectroscopy, an optical antenna is used to localize incident radiation and initiate a local optical interaction with a sample surface, thereby enabling optical images with 10 nm resolution as well as allowing simultaneous spectroscopic analysis of the sample-by moving the antenna pixel by pixel over the sample surface a hyperspectral image of the surface is produced (see p. 91).
Similarly-but on a much different scale-imaging spectrometers also combine image and spectroscopic data. They have been widely used for many years by government and specialized research labs for such applications as airborne remote sensing of Earth. Now, though, these spectrometers are beginning to enter the commercial arena and will doubtless find a number of new applications (see cover and p. 63).
And speaking of changing the rules, the combination of optics with microfluidics is creating another emerging family of “optical wonders”-small integrated devices suited to biophotonic applications. Such devices include highly reconﬁgurable optical waveguides and beamsplitters, sensitive optoﬂuidic molecular sensors based on very high-ﬁnesse microtoroids, and optoﬂuidic switches (see p. 85).
Stephen G. Anderson
Associate Publisher/Editor in Chief