(Press-News.org) WASHINGTON -- In a new study, researchers have shown that 3D printing can be used to make highly precise and complex miniature lenses with sizes of just a few microns. The microlenses can be used to correct color distortion during imaging, enabling small and lightweight cameras that can be designed for a variety of applications.
"The ability to 3D print complex micro-optics means that they can be fabricated directly onto many different surfaces such as the CCD or CMOS chips used in digital cameras," said Michael Schmid, a member of the research team from University of Stuttgart in Germany. "The micro-optics can also be printed on the end of optical fibers to create very small medical endoscopes with excellent imaging quality."
In The Optical Society (OSA) journal Optics Letters, researchers led by Harald Giessen detail how they used a type of 3D printing known as two-photon lithography to create lenses that combine refractive and diffractive surfaces. They also show that combining different materials can improve the optical performance of these lenses.
"3D printing of micro-optics has improved drastically over the past few years and offers a design freedom not available from other methods," said Schmid. "Our optimized approach for 3D printing complex micro-optics opens many possibilities for creating new and innovative optical designs that can benefit many research fields and applications."
Pushing the limits of 3D printing
Two-photon lithography uses a focused laser beam to solidify, or polymerize, a liquid light-sensitive material known as photoresist. The optical phenomenon known as two-photon absorption allows cubic micrometer volumes of the photoresist to be polymerized, which enables fabrication of complex optical structures on the micron scale.
The research team has been investigating and optimizing micro-optics made with two-photon lithography for the past 10 years. "We noticed that color errors known as chromatic aberrations were present in some of the images created with our micro-optics, so we set out to design 3D printed lenses with improved optical performance to reduce these errors," said Schmid.
Chromatic aberrations occur because the way that light bends, or refracts, when it enters a lens depends on the color, or wavelength, of the light. This means that without correction, red light will focus to a different spot than blue light, for example, causing fringes or color seams to appear in images.
The researchers designed miniature versions of lenses traditionally used to correct for chromatic aberrations. They began with an achromatic lens, which combines a refractive and diffractive component to limit the effects of chromatic aberration by bringing two wavelengths into focus on the same plane. The researchers used a commercially available two-photon lithography instrument made by NanoScribe GmbH to add a diffractive surface to a printed smooth refractive lens in one step.
They then took this a step further by designing an apochromatic lens by combining the refractive-diffractive lens with another lens made from a different photoresist with different optical properties. Topping the two-material lens with the refractive-diffractive surface reduces chromatic aberrations even more, thus improving imaging performance. The design was performed by Simon Thiele from the Institute of Technical Optics in Stuttgart, who recently spun out the company PrintOptics which gives customers access to the entire value chain from design over prototyping to a series of micro-optical systems.
Testing the micro-optics
To show that the new apochromatic lens could reduce chromatic aberration, the researchers measured the focal spot location for three wavelengths and compared them to a simple refractive lens with no color correction. While the reference lens with no chromatic correction showed focal spots separated by many microns, the apochromatic lenses exhibited focal spots that aligned within 1 micron.
The researchers also used the lenses to acquire images. Images taken using the simple reference lens showed strong color seams. Although the 3D printed achromat reduced these drastically, only images taken with the apochromat completely eliminated the color seams.
"Our test results showed that the performance of 3D printed micro-optics can be improved and that two-photon lithography can be used to combine refractive and diffractive surfaces as well as different photo resists," said Schmid.
The researchers point out that fabrication time will become faster in the future, which makes this approach more practical. It currently can take several hours to create one micro-optical element, depending on size. As the technology continues to mature, the researchers are working to create new lens designs for different applications.
INFORMATION:
Paper: M. Schmid, F. Sterl, S. Thiele, A. Herkommer, H. Giessen, "3D Printed Hybrid Refractive/Diffractive Achromat and Apochromat for the Visible Wavelength Range," Opt. Lett., 46, 10, 2485-2488 (2021).
DOI: https://doi.org/10.1364/OL.423196.
About Optics Letters
Optics Letters offers rapid dissemination of new results in all areas of optical science with short, original, peer-reviewed communications. Optics Letters accepts papers that are noteworthy to a substantial part of the optics community. Published by The Optical Society and led by Editor-in-Chief Miguel Alonso, Institut Fresnel, École Centrale de Marseille and Aix-Marseille Université, France, University of Rochester, USA. Optics Letters is available online at OSA Publishing.
About The Optical Society
Founded in 1916, The Optical Society (OSA) is the leading professional organization for scientists, engineers, students and business leaders who fuel discoveries, shape real-life applications and accelerate achievements in the science of light. Through world-renowned publications, meetings and membership initiatives, OSA provides quality research, inspired interactions and dedicated resources for its extensive global network of optics and photonics experts. For more information, visit osa.org.
Media Contact:
mediarelations@osa.org
CORVALLIS, Ore. - Free from human disturbance for a century, an inland island in Central America has nevertheless lost more than 25% of its native bird species since its creation as part of the Panama Canal's construction, and scientists say the losses continue.
The Barro Colorado Island extirpations show how forest fragmentation can reduce biodiversity when patches of remnant habitat lack connectivity, according to a study by researchers at Oregon State University.
Even when large remnants of forest are protected, some species still fail to survive because of subtle ...
DALLAS - May 12, 2021 - Scientists with UT Southwestern's Peter O'Donnell Jr. Brain Institute have identified the molecular mechanism that can cause weight gain for those using a common antipsychotic medication. The findings, published in the Journal of Experimental Medicine, suggest new ways to counteract the weight gain, including a drug recently approved to treat genetic obesity, according to the study, which involved collaborations with scientists at UT Dallas and the Korea Advanced Institute of Science and Technology.
"If this effect can be shown in clinical trials, it could give us a way to effectively treat ...
Astronomers commonly refer to massive stars as the chemical factories of the Universe. They generally end their lives in spectacular supernovae, events that forge many of the elements on the periodic table. How elemental nuclei mix within these enormous stars has a major impact on our understanding of their evolution prior to their explosion. It also represents the largest uncertainty for scientists studying their structure and evolution.
A team of astronomers led by May Gade Pedersen, a postdoctoral scholar at UC Santa Barbara's Kavli Institute for Theoretical Physics, have now measured the internal mixing within an ensemble of these stars using observations ...
Leesburg, VA, May 13, 2021--According to an open-access Editor's Choice article in ARRS' American Journal of Roentgenology (AJR), CT features may help identify which patients with stage IA non-small cell lung cancer are optimal candidates for sublobar resection, rather than more extensive surgery.
This retrospective study included 904 patients (453 men, 451 women; mean age, 62 years) who underwent lobectomy (n=574) or sublobar resection (n=330) for stage IA non-small cell lung cancer. Two thoracic radiologists independently evaluated findings on preoperative chest CT, later resolving any discrepancies. Recurrences were identified via medical record review.
"In patients with stage IA non-small cell lung cancer, pathologic ...
Boston - Pregnant women with symptomatic COVID-19 have a higher risk of intensive care unit admissions, mechanical ventilation and death compared to non-pregnant reproductive age women. Increases in preterm birth and still birth have also been observed in pregnancies complicated by the viral infection. The Centers for Disease Control and Prevention (CDC) recommended that people who are pregnant may choose to be vaccinated at their own discretion with their healthcare provider. However, pregnant and lactating women were not included in Phase 3 vaccine efficacy trials; thus, data on vaccine safety and immunogenicity in this population is limited.
In a new study from Beth Israel Deaconess Medical Center (BIDMC), ...
Despite having been driven nearly to extinction, the California condor has a high degree of genetic diversity that bodes well for its long-term survival, according to a new analysis by University of California researchers.
Nearly 40 years ago, the state's wild condor population was down to a perilous 22. That led to inbreeding that could have jeopardized the population's health and narrowed the bird's genetic diversity, which can reduce its ability to adapt to changing environmental conditions.
In comparing the complete genomes of two California condors with those of an Andean condor and a turkey vulture, UC San Francisco and UC Berkeley scientists did find genetic evidence of inbreeding over the past few centuries, but, overall, a ...
TORONTO, ON - A team of evolutionary biologists from the University of Toronto has shown that Anolis lizards, or anoles, are able to breathe underwater with the aid of a bubble clinging to their snouts.
Anoles are a diverse group of lizards found throughout the tropical Americas. Some anoles are stream specialists, and these semi-aquatic species frequently dive underwater to avoid predators, where they can remain submerged for as long as 18 minutes.
"We found that semi-aquatic anoles exhale air into a bubble that clings to their skin," says Chris Boccia, a recent Master of Science graduate from the Faculty of Arts & Science's Department of Ecology ...
Traffic noise leads to inaccuracies and delays in the development of song learning in young birds. They also suffer from a suppressed immune system, which is an indicator of chronic stress. A new study by researchers of the Max Planck Institute for Ornithology and colleagues shows that young zebra finches, just like children, are particularly vulnerable to the effects of noise because of its potential to interfere with learning at a critical developmental stage.
Traffic noise is a pervasive pollutant that adversely affects the health and well-being ...
New Orleans, LA - Research conducted by an international team of scientists discovered a mechanism that leads to Herceptin resistance, representing a significant clinical obstacle to successfully treating HER2-positive breast cancer. They also identified a new approach to potentially overcome it. The work is published online in Nature Communications, available here.
"This work attempts to understand why some HER2-positive breast cancer patients do not benefit from treatment with Herceptin, which is a generally effective HER2-targeted therapy," explains Bolin Liu, MD, Professor of Genetics at LSU Health New Orleans' School of Medicine and Stanley S. Scott Cancer Center.
The researchers found increased signaling by IGF2/IRS1 (genes involved in ...
MAROANTSETRA, Madagascar (May 13, 2021) - A new study by WCS (Wildlife Conservation Society) looks at the prevalence of human consumption of lemur and fossa (Madagascar's largest predator) in villages within and around Makira Natural Park, northeastern Madagascar, providing up-to-date estimates of the percentage of households who eat meat from these protected species.
Authors from the Wildlife Conservation Society (WCS) describe their findings in the journal Conservation Science and Practice. In Madagascar, the consumption of endangered and protected species, in particular lemurs, ...
