Laser Pointer (LaserPointer) is called semiconductor laser pointer, also called Laser pointer
. It is the simplest and most common application of laser in general schools. As a pointer, it has the advantages that ordinary pointers cannot match.Advantages of using laser pointers for scientific experiments:1) Small size and light weight. The total length of the laser pointer is only six or seven centimeters, which is less than half the length of a general pen. It can be hung on the keychain for convenient
It is easy to carry and use.
2) The pointing is clear and bright. Because the laser beam is thin and the spot diameter is about 2mm, the laser pointer emits red visible light (wavelength is 630-650nm). Although the rated output power is less than 5mw, the power density is large, so there is no need for a darkroom to see Very clear.
3) Low energy consumption, impact resistance and long life. Use 4.5 volt button battery, use it to turn on, not use it to turn off, the power consumption is not large, a battery can be used for a long time.
4) The price of the laser pointer is cheap.Experiment of laser pointer light interference phenomenon:With a laser pointer, experiments such as light interference, diffraction, and polarization become very easy to complete. Depend on
Because the laser has good monochromaticity and good coherence, it is an ideal coherent light source. It is very simple to demonstrate the interference phenomenon of light: cut a circle with a diameter of about one centimeter with black paper or cow or leather paper, and use a thin acupuncture at the center. Use a needle to pierce two small holes, the distance between the two holes should be close, but they can not be connected together to form a hole, unscrew the pen cap of the high power laser pointer
, put the round paper sheet in front of the small lens and screw on the cap. , Shoot the laser in a dark place, such as in a student’s drawer. A few very clear dark stripes will be seen in the red spot with a diameter of 2-3mm, and the interference effect is very good.Laser pointer can do single-hole diffraction experimentPunch a small hole in the center of the paper cut above. The hole should be smaller, and the paper should be dipped in oil or cut into paper with opaque wax paper, so that after the hole is punched, there will be no small holes in the hole. Fiber silk. Similarly, stick the paper sheet in front of the lens of the Green laser pointer
head, screw on the pen head cover, and turn on the switch, you can see that the light spot is larger in the dark place than without the paper sheet, and the light spot is composed of concentric circles of light and dark. Due to the particularity of the laser light-emitting mechanism, the emitted laser beams are all polarized, which makes the teaching demonstration about polarized light simple and easy.