Researchers at the California Institute of Technology (Caltech; Pasadena, CA) have fabricated an optofluidic-microscopy device with a measured resolution limit of 490 ±40 nm, comparable to conventional microscopy. The device does not contain any lens or other bulk optical elements, however. Imaging was accomplished by passing a specimen over an aperture array with LED illumination from above and CCD detectors beneath, effectively taking a line scan of the specimen.
By skewing the placement of apertures diagonally both along the direction of transit and across the width of the sampling channel, the researchers obtained resolution finer than the detector pixel size. The resolution limit along the y-axis (width of the sample channel) was governed by the aperture size. The resolution along the x-axis (direction of flow) depended upon the larger of either the aperture size or the product of the sample velocity and the pixel acquisition time. This device can be built directly onto a CCD or CMOS linear sensor array. With this technology, the researchers aim to build high-resolution microscope systems that will be comparable in size to a cell phone at a small fraction of a conventional microscope’s cost. Contact Changhuei Yang at [email protected].