BACKGROUND:  Far-field optical microscopes, laser scanning confocal microscopes, and 4Pi confocal microscopes can image 3D structures. These microscopes are limited in resolution by the Abbe diffraction limit, especially in the axial z direction. Nonlinear techniques, such as stimulated emission depletion (STED), can break the diffraction limit. Combining STED with 4Pi microscopy has lead to resolution improvements, but this comes at the cost of great expense, alignment difficulty, and the need for multiple different ultrashort laser pulses that require precise temporal synchronization and spatial overlap.

INNOVATION:  The novel method uses optical amplification to enhance the resolution of far-field imaging instruments, overcoming the Abbe diffraction limit. The method can be implemented on an existing microscope as an enhanced function. It works for fluorescence microscopes using CW lasers and does not require the use of expensive ultrafast pulsed lasers. Implementation costs are negligible compared to the cost of the microscope, enabling significant resolution enhancement at practically no additional cost overhead to the instruments. Further, the novel method is straightforward and does not require any complicated alignment, synchronization, or other implementation difficulties.

POTENTIAL APPLICATIONS 

• Laser scanning fluorescence microscopes.
• Fluorescence confocal microscopes.
• Two-photon fluorescence microscopes.
• Microscopic photoluminescence imaging systems.
• Other imaging systems utilizing fluorophores such as fluorescent dyes or quantum dots.

ADVANTAGES

• Enhances resolution and exceeds the Abbe diffraction limit along all three (x, y, and z) dimensions.
• Enhances and increases contrast while increasing resolution.
• Applies to any fluorescence microscope, confocal or nonconfocal, at a negligible cost.
• Eliminates the need for expensive and difficult optical/spatial alignment, multiple laser. optics, and temporal synchronization, typically required for existing schemes.
• Enables the use of quantum dots and fluorescence dyes.

DEVELOPMENT-TO-DATE:  The technique has been reduced to practice and demonstrated in laboratory experimentation.

Reference: UCLA Case No. 2006-697