How it works
Why waste mechanical power to pulverize hardrock when we can cut smooth blocks fast, efficiently and with simpler equipment?
Conventionally, lasers cannot cut deep kerfs in rock. Through filamentation, they can cut deeper. However, most importantly, the filaments are mainly driven by electricity. Thus, higher cutting speeds can be obtained with smaller laser sources and lighter equipment.
Plasma filamentation is obtained with laser light pulsed to high energy density. They follow a straight line pathway through gases. However, those filaments have short duration and are typically some hundreds micrometers in thickness. Through spectral broadening, the filaments can be made thinner and directly connected to an electrical supply to reinforce the plasma temperature and luminosity, thereby enabling non-pulsed cutting with high speed.
Efficiency and speed
Tunnel boring efficiency is measured by specific energy per tunnel volume (MJ/m3). With thin kerfs and large blocks, the specific energy can be reduced by a factor of 10 or more compared to classical tunnel boring machines. The building blocks produced are more easily handled and transported faster by conveyor belts than pulverized masses.
While mechanical tunnel boring is principally limited, i.a. due to overheating, non-mechanical boring can provide a scalable speed level. The more electricity available, the more intense filaments and faster cutting. The power is distributed to a scalable number of optical units working in parallel. The speed limit is tied to the conveyor belts and the robotics for handling the blocks, which in principle can exceed a hundred times faster than the common boring speeds today.