National Research Council of Canada

Shoude Chang

Zhenguo Lu

Philip J Poole

Jiaren Liu

Chander P Grover

Ming Zhou

Costel Flueraru

Chunying Song

Ye Tao

Marc Rioux

Heping Ding

Zhiyi Zhang

Salima Alem

Erroll Murdock

Youxin Mao

Sherif S Sherif

Xinping Liu

A technique for narrowing a linewidth of a plurality of lines of a coherent comb laser (CCL) concurrently comprises providing a mode-locked semiconductor coherent comb laser (CCL) adapted to output of at least 4 mode-locked lines; tapping a fraction of a power from the CCL from the laser cavity to form a tapped beam; propagating the tapped beam to an attenuator to produce an attenuated beam; and reinserting the attenuated beam into the laser cavity, where the reinserted beam has a power less than 10% of a power of the tapped beam. The reinsertion allows the CCL to be operated to output the mode-locked lines, each with a linewidth of less than 80% of the original linewidth. By propagating the tapped and attenuated beams on a solid waveguide, and ensuring that the secondary cavity is polarization maintaining, improved stability of the linewidth narrowing is ensured.

Stable linewidth narrowing of a coherent comb laser

Methods are provided for fabricating photodetector arrays using passive matrix addressing technology. The photodetector arrays use a pair of switching diode and photo diode to overcome crosstalk issues within the passive matrix. The switching diode and the photo diode of each pixel may be connected using a cathode-to-cathode connection, or an anode-to-anode connection. The photodetector arrays are fabricated by assembling on a first substrate, an array of photodetector pixels comprising a switching diode and a photo diode, providing conductive lines for each row of the array and conductive lines for each column of the array, and attaching a second substrate to the first substrate. The photodetector array may also be fabricated by assembling on a first substrate an array of switching diodes, and assembling on a second substrate an array of photo diodes, and bonding the first and second substrates together.

Methods of manufacturing printable photodetector array panels

A scanning optical head for a catheter is locally controlled by a motor at an insertion end of the catheter uses a hollow motor through which a longitudinal optical path of the catheter passes. This permits the motor to be positioned between a control base of the catheter and avoids rotating the whole fiber, and therefore makes the beam scanning stable and accurate. In addition, because there is no coupling component, it also eliminates the light reflection between additional surfaces as well as varying fiber birefringence, which becomes a cause of noise when imaging the deep structure.

Optical catheter with rotary optical cap

The invention provides an interferometric system and method for quadrature detection of optical characteristics of a sample. The system includes a Mach-Zehnder interferometer providing a variable optical delay between light collected from the sample and reference light. The Mach-Zehnder interferometer has an output M&#xd7;N coupler with N&#x2267;3 output ports. Two differential detectors, each having two input ports coupled to a different two of the N output ports of the M&#xd7;N coupler, produce first and second electrical signals having an interferometric phase shift. A processor is provided for computing real and imaginary parts of a complex refractive index of the sample from the first and second electrical signals by using complex deconvolution.

Interferometric system for complex image extraction

An optical based identification system that is easily deployable and can be used in broad daylight. Fluorescent semiconductor nanocrystals (quantum dots) that fluoresce at specific wavelengths are distributed in a suitable polymer. The resulting mixture can then be applied as paint or on an adhesive label for application to a portion of any equipment or member of a friendly unit. The system also has a corresponding detectional processing unit which may be mounted on ordnance or on any other equipment such as aircraft. The detection unit uses a laser, which when active, causes a laser beam to strike the paint or adhesive able applied to the friendly unit. This causes the quantum dots to fluoresce. The fluorescence of the quantum dots can be detected by the sensor portion of the detection/processing unit. The sensor portion then transmits the data generated by the detected fluorescence to a data processing portion detection/processing unit such as a corresponding signal to the equipment operator or, if the unit is mounted on ordnance that has been launched to the warhead to deactivate the warhead. To overcome the effects of broad daylight on an optical system, the quantum dots can be detected by the sensor portions of the detection/processing unit. The sensor portion then transmits the data generated by the detected fluorescence to a data processing portion which decodes the data. If the decoded data indicates a friendly unit, the detection/processing unit sends a corresponding signal to the equipment operator or, if the unit is mounted on ordnance that has been launched to the warhead to deactivate the warhead. To overcome the effects of broad daylight on an optical system, the quantum dots are engineered to fluoresce at wavelengths corresponding to the absorption lines of the solar spectrum, more commonly known as Fraunhofer lines.

Object identification using quantum dots fluorescence allocated on Fraunhofer solar spectral lines

A method of extracting a tomographic image of a layer within a body by optical coherence tomography, involves capturing three images, namely a non-interference background image, a first interference-fringe image of said layer, and a second interference-fringe image phase-shifted relative to the first interference-fringe image. The tomographic image is obtained by mathematically combining the three captured images. In a preferred embodiment random noise is removed by averaging and inter-layer effects are removed by applying a compensation function. This system is then used to extract the 2D cross-sectional images encoded in a multiple-layer information carrier.

Full-field optical coherence tomography and its application to multiple-layer information decoding

In a method of coding and retrieving information by using the unique emission properties of the semiconductor nanocrystals (quantum dots) for the identification of valuable documents, articles and objects, a carrier medium is prepared containing quantum dots selected to give the carrier medium defined fluorescent emission characteristics encoding predetermined information. The carrier medium is then applied to the object, preferably in the form of an ink.

Spectral coding by fluorescent semiconductor nanocrystals for document identification and security applications

Faces are one of the most commonly recognized features among people. According to the invention a system for recognizing intensity images of faces is provided. Intensity images of a face are captured and normalized. The intensity images are transformed, filtered and then transformed again. The filter is based on a three-dimensional image of a face against which the intensity image is being compared. The result is a form of correlation that is substantially illumination independent.

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Ottawa, Canada

Shoude Chang