Silicon Nano Pillar Sensor (SiNaPS)

Background

Optical sensors based on plasmonic interactions and fluorescence have been used in sensing applications. However, these methods typically involve expensive imaging spectrometers and light sources to measure spectral changes.

Description of the invention

Inspired by butterfly wings and through the use of low-dimensional silicon nanowires arranged in an array, University of Waterloo researchers have developed a refractive index sensor which uses an off-the shelf white light source such as white LEDs, and an imaging camera to sense changes in colour. Silicon nanowires arrays reflect vivid colours which are sensitive to the refractive index of the medium surrounding them. Thus, by simply measuring the change of colour, the refractive index changes in surrounding region can be ascertained. A refractive index sensor with a resolution better than 1x10-4 has already been demonstrated allowing the technology to be used in multiple fields. Further improvements on the invention are underway and integration with micro-fluidic channels to create a lab-on-a-chip device is also being investigated. The sensor uses low cost silicon material and a simple imaging camera which potentially allows for inexpensive optical sensors (less than $50).

Advantages

The sensor has the refractive index resolution of photonic integrated circuit based sensors at a fraction of the cost. The simplicity of detection allows for it to be used by virtually anyone with no technical training. The other advantage is the small and compact size of the final product which allows mobile sensing. Also, the colour changes are insensitive to changes in temperature, making the invention a unique optical sensor.

Potential applications