Digital Holographic Microscope
The SHAMU (Submersible Holographic Astrobiology Microscope with Ultraresolution) group is working to develop a digital holographic microscope (DHM) to observe microbial motility on earth and eventually in space. It is believed that microbial motility suggests life, and detection of motility in an extraterrestrial liquid sample would suggest extraterrestrial life. Fortunately, it is becoming more and more evident that liquid water and ice are present in outer space.
DHM uses optical interference to record information from a 3D volume into a single hologram. The hologram can be post-processed to achieve ideal focus on multiple planes, enabling the imaging of an entire volume with no moving parts. Additionally, both phase and intensity information are captured by the hologram: phase information allows even transparent samples to be detected.
The group has successfully built an instrument and deployed it in Nuuk, Greenland. In Nuuk's icy cold, extraterrestrial analogous environment, motility was undeniably detected.
For more information, please see: http://motility.caltech.edu