1. Resolution

The diameter of the photosensitive surface directly affects the resolution of the detector. In general, the larger the diameter of the photosensitive surface, the higher the resolution. For applications that require high-precision measurement, such as observing the diameter and shape of light sources in astronomy, it is necessary to choose a detector with a larger diameter of the photosensitive surface.

2. Response speed

The larger the diameter of the photosensitive surface, the slower the detector's response to light. This is because a larger light receiving area requires a longer time to accumulate light energy and reach the detection threshold. On the contrary, detectors with smaller photosensitive surface diameters have faster response times and are usually suitable for measuring rapidly changing scenes, such as LiDAR.

3. Signal to noise ratio

The diameter of the photosensitive surface can also affect the signal-to-noise ratio of the detector. As the diameter of the photosensitive surface increases, the noise of the detector signal also increases, reducing the signal-to-noise ratio. Therefore, when selecting a detector, it is necessary to balance factors such as resolution, response speed, and signal-to-noise ratio based on specific application scenarios.

3、 The diameter of photosensitive surfaces for different types of detectors

1. Silicon photocell

Silicon photocells are a common type of detector, with a photosensitive surface diameter typically between 1mm and 3mm. For precision measurement scenarios that require high resolution, silicon photocells with smaller photosensitive surface diameters can be selected.

2. Photomultiplier tube

A photomultiplier tube is a detector that receives a single photon, with a photosensitive surface diameter generally ranging from 10mm to 30mm. Compared to silicon photocells, photomultiplier tubes have higher sensitivity and are suitable for low light intensity scenarios.

3. CCD and CMOS image sensors

CCD and CMOS image sensors are commonly used image photodetectors, with photosensitive surface diameters ranging from 1/3 inch, 1/2.7 inch, 1/2 inch, etc. Large CDDs can reach several inches in size. When selecting based on application scenarios, factors such as resolution, response speed, and signal-to-noise ratio need to be considered.

4、 Summary

This article provides a detailed analysis of the impact of photosensitive surface diameter on detector performance, including resolution, response speed, signal-to-noise ratio, etc., and provides specific examples of several common types of detectors. When selecting a detector, it is necessary to comprehensively consider various factors based on specific application scenarios to achieve the optimal detection effect.