What is Nano-Optics?

Nano-optics is a branch of Optical Engineering which measures the optical properties of materials at nanometer scales. Nano-optics can detect light coming from structures with a very high spatial resolution. Therefore, nano-optics is very beneficial for studying the optical properties of nanostructures.

One of the most common optical experiments is measuring spectra. A spectrum is basically the Intensity of light versus the wavelength of light, in other words, the brightness of light versus the color of that light.

The spectrum of materials and nano-structures tell us valuable information about them. With nano-optics we are able to measure spectra of many, discrete, small areas (or individual nano-particles).

A relatively basic way to measure the spectra of materials is with micro-photoluminescence (µPL). A microscope objective, essentially a lens, focuses light to a small area, on the order of magnitudes of a couple of microns. This area is limited by imperfections in the lens along with other aberrations.

To overcome these limitations, nano-optics uses other techniques and nanostructures, such as the optical fiber probe. An optical probe, or fiber tip, can focus light into areas that are nanometers in diameter.

Light is focused out the diameter of the fiber tip which is nanometers in diameter. Usually light is limited by the diffraction limit: the size which light can be focused is limited by the wavelength of that light. With nano-optics, this limit can be overcome.