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The representation of an artist’s slight sail in the room above the earth. | Credit: NASA
Scientists of the California Institute of Technology have taken a big step into the development of layers of lights that could one day take tiny space with distant star systems.
The new findings describe a method for measuring the power of the laser light on so -called “ultra -thin membranes”. This is a research that could help promote the vision of the groundbreaking Starshot initiative of laser-driven space.
Introduced in 2016 in the late period Stephen Hawking and Tech investor Yuri Milner, Breakthrough Starshot Alpha CentauriThe nearest star system for the earth. The plan is based on powerful lasers Earth If you drive delicate, sailing -based probes into the cosmos like the wind for sailing boats here on the planet, it enables the craft to reach record -breaking speeds without a chemical exercise.
Lights are a generic form of Solar sailSince you use the radiation pressure from a light source to create a drive. The radiation pressure is the transmission of impulse by radiation, which hits a surface like the wind on canvas sails here on earth. Photons have no mass, but they still transmit part of their dynamics when they hit an object and push it so easily. A single photon does not make a big difference, but trillions and trillions of photons, all of which hit a surface, add up, especially in the vacuum of Space.
Radiation in the form of sunlight is therefore sufficient to advance thousands of miles before the course Mars Or other planets.
However, a higher-energy version of this phenomenon could use a floor or room-based laser beam to push a light approach to a spaceship in a clear manner. Since the beam provides a source of constant pressure on the sail, the cumulative effect of this radiation pressure ensures speeds that are much faster and more reliable than you could get with chemical drive of complicated rockets.
“The light email will drive faster than any former spaceship with the potential to open interstellar distances to lead the exploration of space vehicles” CalTech instruction.
Measurement of light power on a sail
The ATWATER team developed a test platform to measure how laser power on a microscopic “trampoline” of silicon nitride, only 50 nanometers thick. The miniature sail, a square sheet 40 micrometers on each side, is bound and vibrated on the corners by silicon nitride springs when they are hit by a laser. By recognizing these tiny movements, researchers can calculate the power of the laser beam and its strength.
“There are numerous challenges in the development of a membrane that could ultimately be used as a stratification. “But before we can start building such a sail, we have to understand how the materials react to radiation pressure from lasers. We wanted to know whether we can only determine the force on a membrane by measuring their movements. . “
The main authors of the study, postdoctoral student Lior Michaeli and the doctoral student Ramon Gao, built a specialized setup with the name Common Path interferometer. This enables a precise measurement of the movement of the membrane by speaking background noises such as small vibrations in the laboratory of devices or even humans.
“We not only avoided the undesirable heating effects, but also what we have learned about the behavior of the device in order to create a new method for measuring the power of light,” said Michaeli. GAO added that the platform can measure from the side of movement and turns and paving the way for future lights of lighting, which can correct themselves when they drain from the laser beam.
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Ultimately, the team hopes to integrate advanced nanomaterials and meta materials in order to stabilize the light school during their trip. “This is an important springboard to observe optical forces and torques that can have a freely accelerating layering of lights drive with the laser beam,” said Gao.
There are several light sailing projects in progress, and NASA used a solar sail last yearalthough There have been some mechanical problemsemphasize the importance of research by the CalTech team to further refine the design of these sails.
The results were published on January 30th in the magazine Natural photonicsPresent