Friends have a very cheap red laser pointer, he authorized me to disassemble. I wanted to remove the convex lens of the laser head and let the light disperse. The results of those who know that this cheap laser pen is not even screwed into the thread, but stuffed into the glue after the stick. So after twisting the laser pen on the torn apart. At present the projector application in education, training, business show industry suffered a "application crisis". We can see, inside the parts are also very bleak. A small circuit board, which is actually only a switch and a small resistance, so do not have to care. Interestingly, precisely because of its shabby, laser diodes are exposed directly to the outside. So a small piece of things, in fact, is an epoxy board, copper on both sides. The laser pointer 5000mw diode emits light in the middle of the small protrusion above. That is a piece of square things, this is the legendary laser diode deity, and its side length of about 0.1 mm (see magnification 100 times the scale on the map). Its upper and lower surfaces are positive and negative. The upper surface through a line connected to the above large copper plate, the lower surface directly with a conductive adhesive in the following copper plate. The luminous layer in the middle of this square thing, we can not see. Approximately 0.0001 mm (100 nm) thick. The laser diode is a great invention. It was developed rapidly after the advent of gas lasers (1960s) within a year or two. Think about it, when the gas lasers are a few meters long monster, costly. And the researchers can produce only the millimeter of the size of the diode, can also produce laser. This is indeed due to the laser principle and the physical properties of various materials is extremely profound understanding and creative applications. I have read a memoir of one of the inventors of the laser diode. He said that at that time there were several research groups in the United States trying to make solid-state lasers. They are good friends with each other, the competition is also very intense. There are many times in the history of science, a good friend after a scientific research competition against the enemies. However, 3000mw laser pointer diodes are manufactured by different research groups, these good friends are still good friends. This is an unforgettable history. See the microscope line that thin line (probably a very fine gold line), I am very intimate. Because the usual step in my experiment is to use a hand-held tweezers under the microscope to stick the 0.01 mm gold wire to a designated 0.2 mm square box. And then use silver-containing glue to stick the two ends of the line. The key is the hand to be extremely safe, your pulse jump a little heavy, may be the hands of the thin line to the I do not know where to go. The skills of this connection I have been practicing consummate, unmatched world. Everyone in the lab asked me to help them do the job. Later, the laboratory improved the technology, you can use the machine to do this thing, and I like the veteran of the community, absolutely lost the market. The cheap laser diode is not bad. It is very open in the direction perpendicular to the plane of the high power laser pointer diode. One of the criteria for measuring laser diodes is its polarization. Good polarization, the light emitted in the non-laser components less. The following video shows that the laser has a good polarization. And the direction of polarization is parallel to the laser diode. That is, the light field in the light field is about vibration. Life of the polarizer is everywhere, a lot of sunglasses is polarizer. So it can be used to test your laser pen.