The following are the main points to pay attention to: the wavelength you need, and if the spectral parameters are required, you need to confirm the power you need to use (such as spectral linewidth, wavelength stability, etc.). In general, you choose the required spot requirements that are slightly larger than you need to use power, similar to the environmental conditions that need to be illuminated, the stability of the operating distance, the output power, and generally these are the main environmental conditions above. There are some parameters to look at the specific requirements, the higher the performance requirements, the higher the price, the general choice can meet the use of the parameters can be