SILSEF nanopatterning technologies are well suited for use in the optics domain. Indeed, micro-nano structures can be used for various application such as diffraction grating for spectrometer, antireflection patterns, plasmonic effects for bio detection, or light management. SILSEF catalogue of patterns permits the demonstration of principle of a given function. Further development can be made using dedicated patterns.
At SILSEF, antireflective treatments are realized by transferring nanostructures into a substrate or a deposited thin film on its surface. Those structures are based on the so called “moth-eye effect” and acte as an adaptative index layer which simulate a low optic index at the tip of the nanostructures and gradually increases to match the index of the substrate.
This technology allows an effective treatment on a wide spectral band and a large range of incident light angles. The developped processes do not require the use of expensive equipments and can be applied on large surface, plane or curved and on a wide range of materials.
A diffraction grating is an optical element having the ability to diffract light by a periodic variation of its profile and / or its index (hologram). The diffraction gratings have the property of deflecting angularly a monochromatic beam as well as angularly separating the wavelengths of a polychromatic beam.
Diffraction gratings have interesting properties for who wants to “manipulate” light. It is possible to separate a monochromatic incident beam into several beams or to angularly separate the different wavelengths of a polychromatic source. It is also possible to play on different grating’s parameters such as the period, the material, the depth to obtain the desired diffraction intensity .
In a PET scanner detector, the high refractive index of the scintillator crystal causes a large number of the produced UV-vis photons to remain trapped inside the crystal: therefore up to the 70% of the light produced is not collected by the photodetector. Also, the spatial resolution and the sensitivity of existing PET systems suffer from this low collection efficiency of photons.
SILSEF developed solutions with CERN consisting in:
- Light extracting layers can be deposited/fabricated on the exit surface of the scintillator crystal in order to increase the number of photons extracted.
- A possible light extraction layer is a nano-patterned thin film of a material with refractive index higher than the LYSO scintillator (n > 1,8): this diffraction grating is referred to as ‘photonic crystal’ (PhC).
Visit www.napa-technologies.com for further details.