In a quiet scientific park on the outskirts of Salamanca, in front of an abandoned building that was destined to be a center for the study of ham and remained in the bones, the Pulsed Lasers Center of Salamanca stands. It is a beautiful modular construction on which an orange sun of autumn bounces, worthy heiress of those buildings with stone Frank of Villamayor that they have made the university city famous.
As if it were the New Cathedral of Salamanca, the construction of the Pulsed Lasers Center (CLPU) has also been a long process. It all started back in 1995, with the idea and tenacity of Óptica Luis Roso, head of the center. Roso had spent a time in the US and on his return he thought that, why not, it would be interesting to build an installation comparable to those he had seen in North America. A sufficiently advanced and versatile place so that scholars of the light of the whole planet could come to carry out their experiments. Sunlight takes about eight minutes to reach Earth, but getting the go-ahead from the public administration takes much longer.
Building a laser is not a simple process either. In fact, it took two years to do it, plus another two years to create the conditions in which it could work. The particularity of the CLPU is its versatility, since it is a "three in one". There are three lasers of different powers: the VEGA 1, the VEGA 2 and the VEGA 3, the jewel in the crown, one of the few in the world capable of "shooting" a petawatt, or what is the same, one billion million watts (in numbers, 1,000,000,000,000,000 watts). If they are not good at sciences, Luis Roso explains it with a comparison: "The Spanish electric grid is about 40 gigawatts … and then come the terawatts and the petawatts. A petawatt can be about 3,000 times the power of the Spanish electricity grid. "
- Oncology and metal ablation
Luis Roso does not like science fiction very much. Your scientific brain does not understand it. It is incomprehensible to him that the lasers of Star Wars, for example, be limited to one meter. What he likes, and a lot, is Hergé. His office is presided over by a reproduction of Tintin and the seven of crystal balls, those that surround Professor Tornasol. When he wants to explain what he does in the ultra-intense Ultra-Light Pulsed Laser Center he directs, he points out the cover: "We produce a tiny ball smaller than a pinhead. A 10 micron microscopic pellet. " Aware that we only understand what we see, there is a table full of objects that help us understand what a pulsed laser is: a paper circle 24 centimeters in diameter that represents a beam of light: "What we do is create little balls of light that go through this paper ".
Roso believes in the power of light. But not in a spiritual way, but in a scientific way. You can spend hours unraveling the importance of knowing how it works, and why lasers are everywhere, from photo cameras to LEDs, although, according to Roso, "when you talk about lasers, nine out of ten people think about myopia operation and in hair removal. It has nothing to do with what we do here. Here experiments are done on how to apply lasers to oncology, for example, or to the ablation of metals. With the pulsed we wanted to give the idea that there is something in our facilities that is not normal ".
- Crystals of 150,000 euros
The lasers are in the subway. The room immediately before them does not announce the scientific prodigy that takes place in the next room. It has a certain appearance of a warehouse mixed with a security post, with its screens and its space for researchers to leave their equipment. If you look carefully, however, you will see three buttons: they are the ones that have to be tightened to produce the petawatt shot and that each corresponds to a different person in charge: the internal investigator, the external one, and the person in charge of security. In an adjacent corridor, is the cooling equipment, with the appearance of cephalopod that these equipment have full of hoses and gutters.
The jewel in the crown, the laser system, is in a white room in another building, even if it looks the same. And what is called the "bunker" is the area of the experimentation area; where the laser beam impacts once it leaves with its final power. The bunker consists of isolated concrete blocks with an antivibration slab. Every precaution is small: the smallest thing could change the direction of the beam of light and cause the misalignment of the expensive device.
So much so that, when we are shown the guts of the ingenuity, its labyrinthine network of mirrors and crystals, the diffraction gratings that compress the pulse, we will be asked not to speak for fear that the saliva will disturb the journey of light. This is where Luis asks us to refrain from photographing. Each of the titanium-sapphire crystals, for example, is worth 150,000 euros. There are optical tables, vacuum chambers and compressors that look like cryogenicization cameras of a science fiction movie and that would support the weight of an elephant or a whale. "Many of the pieces are unique designs, created to measure for months in collaboration with companies and researchers."
Of course, you have to put on gowns and other equipment to protect yourself from radiation. "Our laser is infrared. According to current legislation, this means that we are not a radioactive installation, but because they are so intense, we are, because we accelerate protons and electrons. We have spoken with the Ministry and we have made progress in demonstrating that the legislation was wrong. The National Security Council has been very receptive. "
We move away from the light, from VEGA 3 and its petawatt. With our brain of letters, we can only think of Hergé and his Tintin. He who, in The mysterious star, made appear in his cartoons the fictional professor of the University of Salamanca Porfirio Bolero y Calamares, member of an expedition to the Arctic. Today it is Luis Roso who receives researchers from Japan, Canada and the United States at the CPLU. Something has changed the story. And it has been for the best.