Researchers at UCLA have built a cheap, optics-free holographic
microscope capable of detecting bacteria like E. coli in things
like water, food, and blood. And by cheap, we mean really cheap.
The researchers say it costs less than $100 to build. The
microscope has two ways of analyzing samples: a transmission
mode and a reflection mode. The transmission mode is good for
transparent media, like thin slices of a sample or clear
liquids. In this case, the microscope’s laser can easily
penetrate and analyze microscopic objects. For denser, more
solid samples the microscope uses holography to generate a 3-D
image of the sample that can be beamed to remote computers for
further analysis if necessary.In reflection mode, the microscope
basically splits the laser beam using a mirror. It then uses one
half of the beam to illuminate the sample. On the other side the
sample beam and the control beam are recombined. Some “clever
mathematics” can then use resulting the changes in the beam to
generate a 3-D image of the ob