4/24/2023 0 Comments Scansion for dwelled![]() In this mode, the non-resonant scanner can be used for photoactivation or photobleaching of selected regions of the specimen followed by subsequent high-speed imaging with the resonant scanner to observe recovery or diffusion of the photoactivated species in real time. Perhaps the most advanced feature of the A1R scanning unit is the ability to perform hybrid scanning using both scanners in tandem. Confocal zoom with the resonant scanner (from 1.5x to 8x) is limited by the requirement of a separate Ronchi grating pattern for each step (discussed below), whereas the non-resonant scanner features a continuously variable zoom range of 1x to 1000x. The resonant scanning system is capable of high speed image capture at rates ranging from 30 frames per second (512 x 512 pixels) to 420 frames per second (152 x 32 pixels) whereas the non-resonant scanner features a maximum scan rate of 4 frames per second at 512 x 512 pixels. An additional free space beam introduction port is included in the A1R MP (multiphoton model) for the ultrafast laser necessary for multiphoton imaging. Illustrated in Figure 1 is a Nikon A1R laser confocal microscope scanning unit equipped with a number of advanced features, including a high-resolution galvanometer-based scanner (4,096 x 4,096 pixels non-resonant) and a high-speed resonant scanner, a continuously variable hexagonal pinhole, spectral imaging capacity, several optical output ports, and a pair of input ports for multiple lasers of different wavelengths. Figure 1 - Laser Confocal Scanning Unit with Linear and Resonant Galvanometer Hybrid Scanning System To overcome the inherently slow speed of confocal microscopes, several manufacturers have introduced instruments equipped with resonant scanning mirrors that are capable of gathering images at 30 frames per second or higher. ![]() In order to acquire images on faster timescales, laser scanning confocal microscopes must be re-engineered to incorporate advanced scanning scenarios that enable the beam to be raster-scanned across the specimen at higher speeds. ![]() This translates to a scan rate ranging from 500 milliseconds to 2 seconds, depending upon the image dimensions. Unfortunately, traditional laser scanning confocal microscopes are limited in acquisition speed by the galvanometer mirrors, which are driven with a linear saw-tooth control signal at the rate of several microseconds per pixel. The growing application of fluorescent proteins in live-cell imaging, however, now requires microscope imaging speeds on the millisecond timescale in order to unravel the intricate dynamics that occur in many biological processes. Laser scanning confocal microscopy has proven to be a useful tool for examining fixed and stained cells, tissues, and even whole organisms at high contrast by the elimination of light originating in regions removed from the focal plane.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |