Building and testing a ruby laser is an appropriate project for high school and college students. Building a ruby laser helps students understand how the laser works and what it can produce. To build the laser, students need a trigger circuit, a rotating prism, to direct the light of the laser, a magnet, a coil of wire and an LED light. The goal of the project is to produce a laser beam that will make the LED light pulse. The challenge to the students is to assemble the circuitry to make the LED light strobe at the same frequency as the rotating prism. Set this project up for students to work in teams to solve the problem.
For science classrooms with a working ruby laser, this is an experiment to demonstrate the laser’s power. First, blow up a red balloon and then blow up a second, blue balloon inside of the red balloon and tie off. Hold the balloon in front of the laser and fire the laser beam. The laser beam will pass through the red balloon because the color transmits the red-colored laser beam, but the blue balloon on the inside will immediately pop when the bean hits it. This project is best done by the teacher as a demonstration before a unit on ruby lasers or to give an example of what kinds of projects students can do.
Students may want to try turning an old PC into a laser for a science fair project. To do this, students will need three parts from an old PC: the power supply unit, the DVD burner and the heatsinks (some models have more than one). They’ll also need an Aixiz module and a constant current driver. Disassemble he DVD burner and remove the laser sled. Take the laser diode and attach it to the Aixiz module. Then, use long lead to connect it to the current driver. The final step involves cutting and stripping the power supply wires to serve as the positive and negative poles. Try out the laser by pointing it toward an object and observing the results. Try the laser on several different objects to test its strength. Always use protective eye-wear when working with lasers.
For this project, students can explain how a ruby red laser works. Ruby red lasers work by exciting the ruby crystals which then produce energy in the form of a laser beam. The laser itself is made of a flash tube, a ruby rod and two mirrors. The flash tube pumps, or excites, the ruby rod which causes the atoms to move and produce photons. The photons then run parallel to the rod and bounce off the mirrors which cause more atoms to move, producing a short wave length beam of red light. Have students diagram the parts of the ruby laser, list ways in which the ruby laser is used and provide photographs of lasers in action.