ABSTRACT
The laser was invented in the 1960s, it installed its wings to optical microscopy. Confocal laser scanning microscopy, or confocal microscopy, has been widely applied in the cutting-edge biological research for its three-dimensional, high-resolution imaging capability. However, it is identified by a different approach for wide-field or confocal microscopy. According to the commutative law, the image will be the same as the wide-field microscopy, if the confocal pinhole is large enough. Because the tissue has different scattering and absorption coefficients, the 700-1300 nm is often regarded as biological window for the optimal penetration depth, if one wishes to image deep into the tissue. The features make it ideal for applications in optical microscopy. In addition, the spatial mode of a laser describes the focal spot size, which is very important in laser scanning microscopy. When laser was invented in the 1960s, it installed its wings to optical microscopy.
