Industrial weapon: ultrafast laser

【Abstract】 Since its inception in the 1960s, lasers have become a “conventional weapon” in people’s production and life: in the industrial field, lasers can easily be used for drilling, cutting and welding; in medicine, the use of high-energy laser Surgical procedures such as retinal detachment can be treated

Since the birth of the laser, laser technology has gradually penetrated into various fields of society. However, with the continuous progress of society and the expansion of market demand, laser technology has gradually been unable to meet production needs, which has also spawned the application demand for ultrafast lasers. appearance.

Since its inception in the 1960s, the laser has become a "conventional weapon" in people's production and life: in the industrial field, the laser can easily perform tasks such as drilling, cutting and welding; in medicine, the high energy of the laser can be used to treat the retina Surgical operations such as peeling; in the military, increasing the laser energy can be made into an infinitely powerful light weapon.

Lasers can be classified into continuous lasers and pulsed lasers according to how they work. Take a flashlight as an analogy. Keeping the button on is continuous work, and quickly turning it on and off is equivalent to sending out a "light pulse". The output power of continuous lasers is generally relatively low, which is suitable for laser communication, laser surgery, etc.; pulsed lasers have high output power, which is suitable for cutting and ranging.

In recent years, ultrashort pulse lasers have become the leading development trend in the field of lasers. The shorter the pulse, the higher the precision of the laser and the greater the energy released. In the laboratory, laser pulses have reached the femtosecond level (one femtosecond equals one quadrillionth of a second). We know that light can travel 300,000 kilometers in one second, but it can only travel a distance as short as the diameter of a human hair in 100 femtoseconds. Not long ago, the ultra-short-pulse laser finishing technology jointly developed by the University of Jena, Robert Bosch Co., Ltd. and TRUMPF Laser was awarded the German Presidential Future Award. Industrial Enterprises.

Ultrafast laser precision machining has two characteristics. One is "cold processing". Traditional laser processing techniques (including nano-lasers) often heat and melt raw materials such as metals and glass. The local high temperature generated by picoseconds (one picosecond is equal to 1000 femtoseconds) and femtosecond lasers can reach 6000 degrees Celsius, which is higher than the surface temperature of the sun. The surface of the affected material is directly vaporized before heat diffusion occurs. The second is "superfine". Ultrafast lasers can focus on ultra-fine space areas, with extremely high peak power and extremely short laser pulses, and have neat cut surfaces, no micro-cracks, no material damage, and no melting areas during processing. Bosch uses picosecond lasers to finely drill the nozzles of diesel engines, increasing engine fuel efficiency by 20 percent. It is reported that by the end of 2013, Bosch will deliver about 30 million auto parts processed with ultrafast lasers.

Ultrafast lasers have broad application prospects. The touch screen of a smartphone is only 0.7 mm thin. Using traditional diamond to cut glass substrates is prone to cracks and burrs. Ultrafast laser non-contact cold processing can overcome these drawbacks. Ultrafast lasers are used for drilling, scribing, grooving and surface texturing of solar cells, which can improve the photoelectric conversion efficiency of cells and reduce production costs. Stents implanted in human arteries for the treatment of blood clots sometimes grow scar tissue, causing the blood vessels to block again, while the surface of the stents processed by ultrafast lasers is very smooth, which greatly reduces the chance of scar tissue growth... In energy saving, environmental protection, In the fields of information, biology, high-end equipment manufacturing and new materials, ultra-short pulse lasers are useful.

The 21st century will be the "Century of Light". The global industry analysis company of the United States predicts that the total output value of the global laser-based optoelectronics industry in 2015 will be close to 1 trillion US dollars. Peter Leibinger, vice president of TRUMPF Laser, pointed out that important technological revolutions in history have occurred in the field of production tools, and they have played a much greater role in changing the course of technological development than specific products. "Ultrashort-pulse lasers are one such tool."

Ultrafast lasers have ultrashort laser pulses, which have important applications in atomic energy level research, laser bond selection chemistry, etc. Therefore, the interaction between ultrafast ultraintense laser pulses and matter is one of the current active research topics. It represents the development direction of today's cutting-edge laser technology.