Available Technology
Plasmonic polarizer
Technology:
Semiconductor lasers with integrated plasmonic polarizers
Markets Addressed
Polarization, both linear and circular, can be one of the key features defining a laser beam. Lasers, which are generally characterized by their monochromatic [single wavelength] and coherent [in phase] properties, can be further defined by their polarization. This allows for a number of improvements to existing applications from communications to instrumentation. It can be used to:
• Increase bandwidth of optical communications. [example: Double the capacity of optical communications by using two orthogonal polarizations]
• Rapidly detect biomolecules exhibiting circular dichroisms. [example: Survey various solvent conditions detectable by circular dichroisms, such as temperature, PH, salinity, etc.]
• Encode data transmissions with a single light source by creating various polarization states. [example: Laser source for quantum cryptography.]
Innovations and Advantages
The technology offered here is the direct integration of a polarizer onto the emission facet of a solid state light source to both increase the robustness and decrease the costs associated with polarizing light. This approach is specifically relevant to semiconductor and other solid-state lasers that have historically had challenges with polarization. Previously, polarization was achieved externally with bulky, delicate and expensive optical components. Here, the technology is able to achieve plasmonic control of a light source, in a compact manner. This is done through the use of metallic gratings combine with subwavelength apertures patterned on a light source emission facet. The technology can be tuned to function well all the way from communication wavelengths to the mid-infrared and terahertz spectrum.
Above is a schematic of a Quantum Cascade Laser emission facet integrated with a plasmonic polarizer capable of producing circularly, elliptically, or TE polarized light, whereby d1 and d2 are distances from the apertures to the first grating grooves on the left and right, respectively, and γ is the grating period. The polarization state of the output light can be controlled by tuning d1 and d2.
Additional Information
Intellectual Property Status: Patent(s) pending
More details about Semiconductor Lasers With Integrated Plasmonic Polarizers can be found at the following link.
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Inventor(s):
Blanchard, Romain
Capasso, Federico
Yu, Nanfang
Categories:
For further information, please contact:
Alan Gordon, Director of Business Development
(617) 384-5000
Reference Harvard Case #3381