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The aim of this study is to investigate laser beam focus shift , or “ defocus ” , using a dynamic focusing unit , in order to increase the laser spot size .
 concept or principle: laser beam; concept or principle: dynamic; process parameter: laser spot size
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: manufacturing standard, machanical property, manufacturing process, material, engineering feature, process parameter, machine or equipment, application, process characterization, enabling technology, biomedical, concept or principle 
Text: {0} 
 Entities: laser beam, dynamic, laser spot size 
Answer:
 concept or principle: laser beam; concept or principle: dynamic; process parameter: laser spot size