Aydogan Ozcan, an assistant professor at University of California, Los Angeles, has developed an attachment for camera phones that turns these devices into microscopes useful for histological and microbiological analysis. Interestingly, the device uses no additional optics but relies on processing the interference patterns of light coming from the samples to recreate the image.
A snippet from the New York Times:
For this electronic system of magnification, inexpensive light-emitting diodes added to the basic cellphone shine their light on a sample slide placed over the phone’s camera chip. Some of the light waves hit the cells suspended in the sample, scattering off the cells and interfering with the other light waves.
“When the waves interfere,” Dr. Brady said, “they create a pattern called a hologram.” The detector in the camera records that hologram or interference pattern as a series of pixels.
The holograms are rich in information, Dr. Ozcan said. “We can learn a lot in seconds,” he said. “We can process the information mathematically and reconstruct images like those you would see with a microscope.”