Inspired by an idea for finding exoplanets with a giant space telescope, a group of scientists is establishing holographic lenses that render visible and infrared starlight into either a concentrated image or a spectrum. The speculative technique, detailed in a post published on October 21, 2021, in Nature Scientific Reports, might be used to create a lightweight versatile lens, numerous meters in diameter, that could be rolled for launch and unfurled in area.
” We utilize 2 spherical waves of light to produce the hologram, which offers us great control over the diffractive grating tape-recorded on the movie, and the result it has on light– either separating light with incredibly level of sensitivity, or focusing light with high resolution,” said Mei-Li Hsieh, a going to researcher at Rensselaer Polytechnic Institute and a specialist in photonics and optics who developed a mathematical option to govern the output of the hologram. “We think this model might be beneficial in applications that need extremely high spectral resolution spectroscopy, such as analysis of exoplanets.”
Telescopes that need to be introduced into space (to benefit from a view unobstructed by Earths atmosphere) are restricted by the weight and bulk of glass mirrors used to focus light, which can realistically span only a few meters in size. By contrast, the lightweight versatile holographic lens– more properly called a “holographic optical element”– utilized to focus light might be dozens of meters across. Such an instrument might be used to straight observe an exoplanet, a leap over current methods that spot exoplanets based on their effect on light coming from the star they orbit, stated Newberg, a Rensselaer teacher of physics, applied physics, and astronomy.
The approach utilizes 2 sources of light, located really close to one another, which create concentric waves of light that– as they travel towards the movie– either build or cancel each other out. Any Fresnel lens will stretch the light a little, but not enough,” said Lin, a specialist in photonic crystals and nano-photonics.
Hsieh, who likewise holds a faculty position at National Yang Ming Chiao Tung University in Taiwain, along with Rensselaer physicists Shawn-Yu Lin and Heidi Jo Newberg, dealt with Thomas D. Ditto, an artist and inventor who developed the concept of an optical space telescope released of standard, and heavy, glass mirrors and lenses. Ditto first operated at Rensselaer in the 1970s and is presently a visiting researcher in astrophysics.
A lightweight versatile lens can focus light or different it into its constituent colors. Credit: Rensselaer Polytechnic Institute
Telescopes that should be launched into area (to benefit from a view unimpeded by Earths environment) are restricted by the weight and bulk of glass mirrors used to focus light, which can reasonably span just a few meters in diameter. By contrast, the light-weight versatile holographic lens– more appropriately called a “holographic optical aspect”– utilized to focus light might be lots of meters across. Such an instrument could be utilized to directly observe an exoplanet, a leap over current techniques that discover exoplanets based upon their effect on light coming from the star they orbit, said Newberg, a Rensselaer professor of physics, applied physics, and astronomy.
” To discover Earth 2.0, we truly wish to see exoplanets by direct imaging– we need to be able to look at the star and see the planet different from the star. And for that, we need high resolution and a really big telescope,” said Newberg, an astrophysicist and specialist in galactic structure.
The holographic optical element is an improved variation of a Fresnel lens, a classification of lenses that use concentric rings of prisms arrayed in a flat airplane to imitate the focusing capability of a curved lens without the bulk. The concept of the Fresnel lens– which was established for use in lighthouses– dates to the 19th century, with modern-day Fresnel lenses of glass or plastic discovered in vehicle lamps, micro-optics, and electronic camera screens.
While Fresnel holographic optical elements– created by exposing a light-sensitive plastic film to 2 sources of light at different distances from the film– are not unusual, existing approaches were restricted to lenses that might only focus light, rather than separating it into its constituent colors..
The brand-new approach enables the designers to either focus light onto a single point or distribute it into its constituent colors, producing a spectrum of pure colors, said Lin, corresponding author and a Rensselaer teacher of physics, used physics, and astronomy. The approach uses 2 sources of light, located really near to one another, which produce concentric waves of light that– as they travel towards the film– either develop or cancel each other out. This pattern of convergence or disturbance can be tuned based upon the solutions Hsieh developed. It is printed, or “tape-recorded,” onto the film as a holographic image and, depending upon how the image is structured, light travelling through the holographic optical aspect is either stretched or focused.
” We desired to extend the light, so that we might separate it into various wavelengths. Any Fresnel lens will extend the light a little, however insufficient,” said Lin, a professional in photonic crystals and nano-photonics. “With our method, we can have very resolution on one end, or very delicate– with each color separated. When the light is stretched like that, the color is great, as pure and as brilliant as you can get.”.
Referral: “Experimental awareness of a Fresnel hologram as an incredibly spectral resolution optical component” byMei-Li Hsieh, Thomas D. Ditto, Yi-Wen Lee, Shiuan- Huei Lin, Heidi J. Newberg and Shawn-Yu Lin, 21 October 2021, Scientific Reports.DOI: 10.1038/ s41598-021-99955-w.
Hsieh, Newberg, Lin, and Ditto were signed up with in the research study by Yi-Wen Lee and Shiuan-Huei Lin of National Yang Ming Chiao Tung University. The study was produced with assistance from the NASA Innovative Advanced Concepts (NIAC) program and a grant from the Department of Education in Taiwan.
