Physics 3901 Labs, Fall 2002

The purpose of this lab was to create a graph of the diffraction pattern created by a laser through a single-slit diffraction grating. The grating was set up on a stand, and the laser placed on a lab jack so the beam went directly through the slit. Next, a light sensor was securely taped onto a cart, which was placed on a low-friction track and adjusted so that the sensor would travel directly through the diffraction pattern along the track. The light sensor was connected through the computer, and set to graph the data on the screen. A small push to the cart resulted in a speed that was too fast for the computer to graph accurately. So a string was attached to each end of the cart, and small masses added to each end until a slow, fairly constant speed was achieved. One large peak and two smaller peaks were visible, but the second peak on each end were not, possibly due to the inaccuracy of the laser projection field onto the sensor, or to a low sensitivity level of the light sensor.

本实验的目的是通过单缝衍射光栅产生一个衍射图样，并绘制该图样。光栅被放置在支架上，激光被放置在实验台上，使光束直接通过缝。接下来，一个光传感器被牢固地粘贴在小车上，小车被放置在低摩擦轨道上，并调整好使传感器能够沿着轨道直接穿过衍射图样。光传感器通过计算机连接，并设置为在屏幕上绘制数据。对小车施加一个小推力，结果得到的速度太快，使计算机无法准确绘制。因此，将绳子分别系在小车两端，并在两端添加小质量块，直到达到一个缓慢且相对恒定的速度。可以观察到一个大的峰和两个较小的峰，但两端的第二个峰不明显，可能是由于激光投影场在传感器上的不准确性，或者由于光传感器的灵敏度水平较低所致。