Photo Revolution: Exploring the Boundaries
A picture is worth a thousand words. Man has believed every single word of that since times immemorial. The early man carved, the medieval man painted and the modern man clicked. Now, pictures are more than a thousand words. Stories and now, science is intervened in the art of ‘clicking’.
Applied Physicists at Harvard School of Engineering and Applied Sciences (SEAS) have literally photographed light and have set new heights for the industry. Federico Capasso, Franceso Aieta,Patrice Genevet, Nanfang Yu, Mikhail a. Kats and Romain Blanchard have created an ultra-thin, flat lens that is basically the wide-angle bulky conventional lens minus the bulkiness, the optical and focus light distortions.
A 60 nanometer thick, this flat lens looks 2-D and very nears the physical limit set by the laws of diffraction. It was created by plating a very thin wafer of silicon with a nanometer sized layer of gold. After that, parts of the gold layer are stripped away, leaving behind an array of evenly spaced, V-shaped ‘nano-antennas’. When light falls on it, the nano-antennas capture the incoming light, hold on to it briefly before releasing it. It is easy to manufacture and operates anywhere between near infra-red to terahertz wavelengths. The nano-antennas are dubbed as “metasurface” and can be tuned for any specific wavelength by altering the size, angle and spacing.
As you might know, the normal conventional lenses are thick and you might have an idea as to how heavy the DSLR lens is. In the conventional lenses, as light travels through the lens, phase delay is created as per requirement. Instead of that, the flat lens creates an instantaneous phase shift at the surface of the lens. The delays are tuned and change the direction of the light like it is supposed to, as in a conventional lens.
Optical aberrations such as ‘fish-eye’ effect, astigmatism and coma are also removed, so the image doesn’t require any corrective complex processes. Their findings were published online in the journal Nano Letters.
Last December, MIT researchers created an imaging system that can acquire visual data at a rate of one trillion exposures per second; a system that might strip ‘Light’ off of its ‘unseeable’ name. The researchers have actually produced a slow-motion video of a burst of light travelling the length of a one-liter bottle, bouncing off the cap and reflecting back. One lens that would capture the ‘Perfect Image” and one equipment that would slow down the world, imagine what this would mean to the scientific world.