Planar photonic crystals target Raman spectroscopy

Founded in 2001 by seven researchers from three departments at the University of Southampton, Mesophotonics has begun to commercialize integrated, planar photonic crystal technology that allows light to be bent, routed, and processed at a sub-millimeter scale.

Feb 15th, 2005

SOUTHAMPTON, ENGLAND - Founded in 2001 by seven researchers from three departments at the University of Southampton, Mesophotonics has begun to commercialize integrated, planar photonic crystal technology that allows light to be bent, routed, and processed at a sub-millimeter scale. During Photonics West last month, the company introduced an application of its technology platform focused specifically on surface enhanced Raman spectroscopy (SERS).

The Mesophotonics technology is based on planar waveguiding photonic crystals made of CMOS compatible silicon materials to fabricate optical manipulation, optical signal processing and electronic circuitry on single substrates using standard silicon foundry processes. The planar photonic crystals are fabricated using standard lithographic techniques.

The function of any particular planar photonic crystal is determined entirely by the geometry of the lattice of air holes, according to the company. Integrated circuits based on this technology platform could conceivably perform several functions, each defined by the distribution of air-holes and connected to each other by planar optical waveguides. The interconnection scheme would be analogous to the integration of electronic circuitry, but the actual device fabrication is envisaged as being much simpler, with all devices perhaps being fabricated in one mask step in which a single air-hole pattern defines all of the devices and interconnections, as well as the functionality of the entire circuit. According to Mesophotonics, potential devices and applications for this technology include switches, splitters, combiners, prisms wavelength multiplexers, delay lines, filters, polarization controllers, mirrors, cavities, feedback devices, beam shapers, gain modification devices, and dispersion controllers.

The company has already introduced a continuum generation chip (CGC) and a Klarite substrate for SERS. The company’s SERS substrates are based on nanometer-scale patterning of a gold surface, such that the photonic crystal controls the surface plasmons that govern the SERS amplification. The SERS substrates are mounted on 75x25-mm microscope glass slides compatible with most micro Raman spectrometers.

The signals generated from the SERS substrates are orders of magnitude more intense than traditional Raman signals and enable detection with low sensitivity detectors and low power lasers, which will open the door to the development of low cost Raman detection systems compatible with volume OEM applications, according to John Lincoln, business development director at Mesophotonics.

“We believe that Klarite substrates offer a new method of controlling surface-enhanced Raman amplification that provides the reproducibility necessary for a vast range of detection applications,” he said.

-Hassaun Jones-Bey

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