Abstract: The difference between quantum mechanics and classical physics is that the energy of the

vacuum is not zero. Normally，due to the small energy，it is hard to measure the vacuum field

directly only when the quantum measurement，such as homodyne detection，is used. Meanwhile，there is

a lack of the experimental demonstration based on quantum measurement in college physics，which

makes the theory of quantum mechanics hard to be un- derstanded. In this paper，a

demonstration instrument for vacuum measurement based on homodyne detection is pro- posed. This

instrument is simple in principle，intuitive in phenomenon，easy to operate and maintain. It makes

up for the blank of quantum mechanics experiment in college physics，which realizes the expansion of

frontier physics in college physics teaching.

Key words: quantum mechanics, homodyne detection, quantum noise, vaccum measurement