New Technique Makes High-Resolution Imaging More Accessible

Scientists at Howard Hughes Medical Institute’s Janelia Research Campus have focused on a new class of techniques called phase diversity to expand the use of adaptive optics for biologists. These techniques allow researchers to work more effectively deep inside tissues than traditional microscopes. The research was published in the journal Optica.

Long ago, astronomers discovered a way to improve the clarity and sharpness of the images of distant galaxies that their telescopes record. Methods that quantify the distortion of light caused by atmospheric conditions can be used to make adjustments to eliminate aberrations.

Microscopists have modified these techniques to produce sharper images of dense biological samples that also warp and bend light. However, many labs are unable to use these approaches, which belong to a family of techniques called adaptive optics, because they are slow, expensive, and difficult.

These phase diversity techniques provide the additional information needed to restore the original image's clarity by adding additional images with known aberrations to a blurry image with an unknown aberration. Phase diversity is an appealing option for microscopy since, in contrast to many other adaptive optics approaches, it does not necessitate significant modifications to an imaging system.

The scientists initially modified the astronomy algorithm for use in microscopy and verified it through simulations before implementing the new approach. They then constructed a microscope with two extra lenses and a deformable mirror, whose reflective surface could be altered.

These small additions to an already-built microscope resulted in the recognized aberration. Additionally, they enhanced the phase diversity correcting program.

The group proved that they could calibrate the microscope's deformable mirror 100 times faster using their novel technique than they could have with previous approaches. They then demonstrated how the technique could detect and eliminate aberrations created at random, yielding clearer images of fluorescent beads and fixed cells.

The technique will next be tested on actual material, such as living cells and tissues, and its use will be expanded to more sophisticated microscopes. The team also wants to improve the method's automation and user-friendliness.

Hopefully, this new approach, which can be implemented more quickly and affordably than existing methods, will eventually make adaptive optics available to more labs, enabling scientists to see more clearly when looking deeply inside tissues.

Journal Reference:

Johnson, C., et al. (2024) Phase diversity-based wavefront sensing for fluorescence microscopy. Optica. doi.org/10.1364/optica.518559