Fraunhofer diffraction of light

Experiment 32 Fraunhofer diffraction of light

【Purpose requirement】

1. Understand the basic optical paths of Fraunhofer diffraction of focal plane reception and far field reception;

2. Observe and study the characteristics and laws of Fraunhofer diffraction patterns of various diffraction elements;

3. Understand the characteristics of white light Fraunhofer diffraction.

【Experimental Principle】

When light encounters an obstacle during propagation, it can bypass the edge of the obstacle. This phenomenon of light deviating from a straight line is called diffraction of light. The diffraction system is generally composed of a light source, a diffraction screen and a receiving screen. The diffraction screen is infinitely diffracted from the light source and the receiving screen, or the incident light irradiated on the diffraction screen and the diffracted light leaving the diffraction screen are both diffraction of parallel light, called Fraunhofer diffraction. The diffraction pattern has the following characteristics: in which direction of the diffraction screen is the beam limited, the diffraction pattern on the receiving screen will expand in that direction; the smaller the aperture line size, the more severe the restriction on the beam, the more the diffraction pattern Expand, the more significant the diffraction effect.

【Experiment content】

1. Far-field receiving optical path; 1) Experimental optical path 2) Optical path adjustment 3) Observe the Fraunhofer diffraction of the diffractive element with the far-field receiving optical path

2. Focal plane receiving optical path;

3. Fraunhofer diffraction of white light.