I think everyone has seen laser shows on stage, disco, festivals, etc. laser pointer usually have a variety of effects. One is the beam effect, which allows the viewer to see the passing beam in the air. The other is a picture effect, which draws a laser pattern on the screen through a moving light spot. The beam effect is very exciting, so there are so many laser shows. The laser equipment used at these times is called a laser projector.
DIY a laser projector is a professional-level challenge. The most important part is called the laser module. Earlier years, helium-neon lasers were used, and multi-color gas lasers are still used for high-altitude projection. New structured solid-state lasers have also been put into use. But the laser is very expensive, and the helium-neon laser with poor quality cannot be directly modulated, so I cannot afford the price of the laser and the modulator. Until Kyoritsu Electric released a reasonable price laser module. Only then did I put this long-conceived project into practice.
The long-distance green laser indicator has other reliable characteristics, such as compact system length, small spherical aberration and fully multilayer coated optical lens system. The amplified coherent light makes it very effective to provide remote lighting for troops on the battlefield. Getting a green laser pen is unnatural, but it is often considered the most visible demonstration tool. The green DPSS laser converts the electric energy into 808nm infrared light, and then sends it to the neodymium crystal, which converts 50% of the electric energy into 1064nm infrared light. The 1064 nm beam is then sent to the KTP crystal, which converts 50% of the 1064 nm green light to 532 nm. There is a long process before I finally get it.
Basically, laser projectors are for the entertainment industry, and the highest-end machines are individually customized according to the required functions. The above figure is a light path diagram of a typical laser projector. It should be seen that the entry-level green laser pointer projector only needs an X-Y scanning mirror to achieve the general effect. In this production, I only made the simplest X-Y scanning mirror. The goal is to clearly display images and animations.
In those old days, helium-neon lasers shine in performances, and "white" mixed gas lasers that can produce several colors at the same time are also used. These gas lasers are both difficult to use and inefficient. In contrast, solid-state lasers, such as semiconductor lasers and semiconductor-pumped solid-state lasers, which have high optical efficiency and are easy to serve, have an increasing share in the market. Most solid-state lasers are red or green in color. When the performance of blue solid-state lasers catches up. outdated gas lasers will be completely replaced by them.