Corning Incorporated

Mark D Salik

Eric John Mozdy

Mark Francis Krol

Stephen Joseph Caracci

Mircea Despa

Guilhem Alibert

Nikolaus Boos

Self-referencing optical sensors and methods are described herein that can be used to detect bio-chemical interactions (e.g., biological binding of antigen-antibody pairs) that occur in for example a microplate. In one embodiment, the self-referencing optical sensor includes a substrate, a lower (reference) waveguide grating structure, a buffer layer and an upper (sensing) waveguide grating structure. This self-referencing optical sensor enables an optical interrogation system to detect a bio-chemical interaction independent of the effect of temperature by measuring a reference signal associated with the lower (reference) waveguide grating structure and measuring a sensing signal associated with the upper (sensing) waveguide grating structure. These two signals are then subtracted from one another to determine a sensing measurement that represents whether or not the bio-chemical interaction occurred that is independent of the effect of temperature. This is all possible because the self-referencing optical sensor has a lower (reference) waveguide grating structure with a thickness that was sized to make a rate of change of a lower resonant wavelength/temperature variation (&#x394;&#x3bb;/&#x394;T) substantially equal to a rate of change of an upper resonant wavelength/temperature variation (&#x394;&#x3bb;/&#x394;T). Several other embodiments of self-referencing optical sensors which have a specific structures and/or a specific compositions are also described herein.

Self-referencing waveguide grating sensors

A grating-coupled waveguide (GCW) and a method are described herein that can be used to detect the presence of a biological substance (e.g., cell, drug, chemical compound) in a sensing region of the GCW. The GCW includes a substrate, a diffraction grating and a waveguide film that has a higher index of refraction than the substrate which has an index of refraction&#x2266;1.5. The relatively low-index substrate effectively increases the sensitivity of the GCW by causing the waveguide mode to shift towards a biological substance located in a sensing region above the waveguide film, thereby increasing the field strength of the mode's evanescent tail in this region. In one embodiment, an array of the GCWs are incorporated within the wells of a microplate.

Substrate index modification for increasing the sensitivity of grating-coupled waveguides

A method of fabricating a grating in a planar optical device by fabricating a surface grating or by photoinscription. For surface gratings, a method comprises providing a substrate material that includes a substrate layer, a first core layer, a second core layer, and a first photoresist layer. An exposure of a grating and a plurality of alignment marks is formed onto the substrate material. The second core layer is etched to form the grating in the second core layer. A second photoresist layer is deposited on the substrate material that remains after the first etching. An exposure of a waveguide pattern is formed in the first core layer. The first core layer is etched to define a first waveguide in the first core layer, where the first waveguide includes a first portion having the surface grating. For photoinscription, the fabrication method comprises providing a substrate material that includes a substrate layer, a core layer, and a first photoresist layer. A first photo-mask that includes a plurality of alignment marks is disposed between the first photoresist and a light source. An exposure of the first photo-mask is performed and the alignment marks are etched into the core layer. A grating is written into the core layer by a photosensitive effect. A second photoresist layer is deposited on the substrate material and an exposure of a waveguide pattern is formed in the core layer. The core layer is etched to define a first waveguide in the core layer, where the first waveguide includes a first portion having the surface grating.

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Paris, France

Mark D Salik