- New research shows a working solar laser that doesn't require a curved mirror collector.
- The result is a flat design like a solar cell that can absorb more, and less direct, sunlight.
- With proof of concept in hand, scientists say they can fine-tune the design even more.
Scientists in Japan and Germany have made a breakthrough in the field of solar lasers—and they’ve changed the game completely.
🤯 You like badass science. So do we. Let's nerd out over it together.
For the first time, they say, a solar laser isn’t simply a supervillain-like huge angled mirror. The new design involves a kilometer of silica fiber that’s doped with a neodymium isotope and then kept in a cylindrical container of solution. The entire assembly acts as a solar collector, but doesn't require the unwieldy size and low efficiency of a curved mirror.
In Communications Physics, the large international team describes the problems with existing solar lasers (SPLs):
“[M]ost SPLs still rely on lens or mirror concentrator systems with concentration factors on the order of thousands. Such concentration optics limit the practicality of SPLs because they are expensive and require very precise tracking of the sun which is challenging at high winds. The system is thus unwieldy, and both the capital and operational costs are prohibitive.”
These SPLs only work in direct sunlight, too, which calls for a solution that can thrive in “diffuse” sunlight—a much more common atmospheric condition.
Their design is what’s called a “flat panel” SPL design, meaning it can be installed much in the same way a traditional photovoltaic solar panel can. The entire cylinder, with solution and fiber inside and a mirror on top, can collect sunlight that’s much more diffuse and at different angles. “The device is planar and passive, and can be easily scaled up without loss of beam quality by connecting modules in series,” the team writes.
The idea is simple:
“The body of the chamber is highly reflective while the top window is a dichroic mirror that transmits incoming sunlight and traps the fluorescence emitted by the sensitizer. The laser-oscillation threshold was reached at a natural sunlight illumination of 60 [percent] on the top window. Calculations indicated that a solar-to-laser power-conversion efficiency could eventually reach 8 [percent].”
The “highly reflective” solution that fills the chamber is Rhodamine 6G, an extremely fluorescent dye that acts as a “sensitizer” in this setup—like a catalyst, but a very specific one that serves only to boost the retention and concentration of sunlight energy. The fiber coiled inside holds and magnifies light the same way “fiber optic” transmits energy.
The scientists tested their setup with different top mirrors to find the most efficient and luminous option, and they found the best option wasn’t the most or least reflective, but somewhere right in the middle. Having tested 50 percent up to 100 percent, the 80 percent reflective mirror created the most powerful laser. “The maximum output-power value was 1.3 mW when an output coupler with 80 [percent] was used,” the team explains.
But even the lowest possible amount of “lasing” was observed by using the 99 percent reflective mirror. While this paper describes proof of concept, experimenting with components and different geometries, the scientists say, could find the most effective design going forward.
“We believe that the developed device constitutes a significant step towards the utilization of SPLs in a wide range of energy conversion applications,” they conclude.
You Might Also Like