1. What is AOTF? What are its benefits? When is it necessary to use the AOTF laser module in a confocal system?
Acousto-Optic Tunable Filters (AOTFs) are employed for precise wavelength selection and filtering. These filters allow for the accurate selection of specific wavelengths or ranges from a wide incident spectrum, superseding traditional fixed bandwidth filters. Their tunability facilitates the adjustment of filter traits such as bandwidth and centre wavelength, providing versatility for diverse optical systems. Typically, when selecting a confocal system, users need to evaluate whether their applications necessitate exceptional wavelength precision (or a constrained wavelength range), and balance the cost associated with the corresponding requirements.
AOTFs offer several advantages, including enhanced spatial resolution, improved signal-to-noise ratio, and reduced autofluorescence. However, they also have some drawbacks, such as significantly increased cost and price of the laser, and relatively low light and signal intensity when used for narrow wavelength output.
2. What are the confocal system's requirements for laser power stability and power tuning accuracy?
Power stability of 1% represents the range of energy fluctuations in laser power over a specified time unit. For instance, with a 20mW output power and stability of 1%, the power fluctuation range is 19.9 - 20.1mW.
The power tuning accuracy of 1% indicates the smallest value users can select for output power. For instance, with a 20mW output power and a power tuning accuracy of 1%, the minimum output value is 0.2mW.
Generally, as single-point and line-scan confocal systems primarily use single-mode lasers with a power requirement of 20mW, a laser energy accuracy and tuning range of 1% is adequate. For those with ample budget, a 0.1% energy tuning range could be considered, although the cost-effectiveness of such precision is relatively low.
3. How do SiPM and PMT differ in the point scan confocal system? What are the implications?
The table below delineates differences between various detectors. Currently, SIMSCOP's detection modules are compatible with both SIPM and PMT, and users can customize their configuration based on their specific budget and performance needs.
Detector |
Sensitivity |
Detection Speed |
Cost |
APD (Avalanche Photodiode) |
High (amplification) |
Fast |
Medium-High |
SPAD (Single-Photon Avalanche Diode) |
Very high (single photon) |
Very fast |
High |
PMT (Photomultiplier Tube) |
Very high (single photon) |
Fast |
High |
SiPM (Silicon Photomultiplier) |
High (single photon) |
Fast |
Medium |
4. What are the differences and characteristics of point scanning, line scanning, and turntable confocal methods?
For a comprehensive analysis, please refer to the provided article link.
5. Why do confocal microscopes offer superior resolution compared to traditional microscopes?
For a comprehensive analysis, please refer to the provided article link.