Laser light

Engineering researchers from Harvard University have demonstrated a laser with a wide-range of potential applications in chemistry, biology and medicine.

Called a quantum cascade (QC) laser nanoantenna, the device is capable of resolving the chemical composition of samples, such as the interior of a cell, with unprecedented detail.

The device consists of an optical antenna fabricated on the facet of a quantum cascade laser that emits infrared light with a wavelength of 7 microns.

The optical antenna consists of two gold rectangles, each 1.2 microns long, separated by a narrow gap of 100nm. Light from the laser illuminates the antenna, resulting in an intense spot of light in the gap seventy times smaller than the wavelength - far smaller than what would be possible by forming a spot of light using a lens.

Because the nanoantenna creates a light spot of nanometric size about fifty to hundred times smaller than the laser wavelength, the light spot can be scanned across a specimen to provide chemical images of the surface with superior spatial resolution.