So, what does a laser "knife" look like? Although its "blade" is just a small dot with a diameter of 0.1 mm, the body of this "knife" is quite large. Generally speaking, the carbon dioxide laser "knife" is nearly 2 meters high, nearly 2 meters long, and less than 1 meter wide. The yttrium aluminum garnet laser "knife" is a little smaller, but it doesn't look like a knife at all. In fact, its main body is a laser, including power supply and console. The laser is fixed. In order for the laser beam to be transmitted to the patient's surgical site according to the doctor's intention, a light guide system called light turning must be equipped.

The light guide system is an important part of the laser "knife". It must be light and flexible so that the doctor can use it easily. Carbon dioxide laser "knives" generally use light-guiding joint arms. It consists of several sections of metal tubes, which are at right angles to each other and can rotate. It is a bit like a joint. The optical reflector is installed at the joint, and the laser beam turns through the reflector. In addition to using light guide joints, the yttrium aluminum garnet laser "knife" and the argon ion laser "knife" are wrapped in a plastic sleeve and then wrapped in a metal hose, which is relatively soft and can be bent freely. The conduction of light in optical fibers is similar to the conduction of electricity in wires. Using optical fibers is much more flexible and lightweight than light-guiding joint arms.