Why do we need to use lensless holographic microscopes
Traditional microscopes can only observe the intensity distribution when observing biological samples. In their natural state, cells are usually in a colorless and transparent state, requiring manual staining and imaging through mechanical focusing, resulting in poor real-time performance. In addition, the internal optical structure of microscopes is complex, and some manufacturer systems are expensive, which is not conducive to commercialization.
The problems with traditional solutions
1. Slow imaging speed: When using traditional microscopy for imaging, manual or automatic focusing is required to find the image plane, which is not conducive to real-time monitoring of biological samples.
2. Expensive price: Traditional microscopes have complex optical path structures, and some microscopes are expensive, which cannot meet the market demand in underdeveloped areas.
3. Possible cell damage: Traditional fluorescence microscopy requires staining of cells in advance to improve imaging quality when observing biological samples, which will reduce cell activity and cause cell damage.
In the real-time detection process of living biological samples, a lensless holographic microscope can be used to achieve real-time three-dimensional imaging without the need for pre-processing of biological samples (such as staining). The reconstructed image of a lensless holographic microscope can be reconstructed using computational imaging algorithms, which can simultaneously achieve a large field of view angle and high resolution, meeting user needs.
The characteristics of scanning electron microscopy
Compared with optical microscopy and transmission electron microscopy, scanning electron microscopy has the following characteristics:
(1) The surface structure of the sample can be directly observed, and the size of the sample can be as large as 120mm x 80mm x 50mm.
(2) The sample preparation process is simple and does not require cutting into thin slices.
(3) The sample can be translated and rotated in three dimensions in the sample chamber, so it can be observed from various angles.
(4) The depth of field is large, and the image is rich in three-dimensional sense. The depth of field of scanning electron microscopy is several hundred times larger than that of optical microscopy and several tens of times larger than that of transmission electron microscopy.
(5) The magnification range of the image is wide, and the resolution is also relatively high. It can be magnified from tens to hundreds of thousands of times, and basically includes the magnification range from a magnifying glass, optical microscope to transmission electron microscope. The resolution is between optical microscopy and transmission electron microscopy, reaching up to 3nm.
(6) The damage and contamination of the sample by the electron beam are relatively small. (7) While observing the morphology, other signals emitted from the sample can also be used for micro area composition analysis.
