X Close
Untitled Document
 
Nano digest is a great step to popularize the nanoscience activities and programmmes..

subhranshu sekhar samal
scientist-C , CNSNT, sathyabama University
Read more...  
SETCOR International Conference on Nanotechnology Nanotech Dubai UAE 2013
Optics '11
Texas Instruments veteran Buss to lead forum on the future of electronics
International Conference on Electron Nanoscopy/ XXXII Annual Meeting of EMSI
Nanotech China
More events...
Untitled Document
 
   News
First flat lens for immersion microscopy
Wed, 17 May 2017
A team of researchers from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) has developed the first flat lens for immersion microscopy. This lens, which can be designed for any liquid, may provide a cost-effective and easy-to-manufacture alternative to the expensive, centuries-old technique of hand polishing lenses for immersion objectives.

The research is described in Nano Letters.

"This new lens has the potential to overcome the drawbacks and challenges of lens-polishing techniques that have been used for centuries," said Federico Capasso, the Robert L. Wallace Professor of Applied Physics and Vinton Hayes Senior Research Fellow in Electrical Engineering at SEAS, and senior author of the paper.

When light hits an object, it scatters. Optical microscopes work by collecting that scattered light through a series of lenses and reconstructing it into an image. However, the fine detailed geometrical information of an object is carried by the portion of scattered light propagating with angles too large to be collected. Immersing the object in a liquid reduces the angles and allows for the capturing of light that was previously impossible, improving the resolving power of the microscope.

Based on this principle, immersion microscopes use a layer of liquid -- usually water or oil -- between the specimen slide and the objective lens. These liquids have higher refractive indices compared to free space so the spatial resolution is increased by a factor equal to the refractive index of the liquid used.

Immersion microscopes, like all microscopes, are composed of a series of cascading lenses. The first, known as the front lens, is the smallest and most important component. Only a few millimeters in size, these semicircular lenses look like perfectly preserved rain drops.

Because of their distinctive shape, most front lenses of high-end microscopes produced today are hand polished. This process, not surprisingly, is expensive and time-consuming and produces lenses that only work within a few specific refractive indices of immersion liquids. So, if one specimen is under blood and another underwater, you would need to hand-craft two different lenses.

To simplify and speed-up this process, SEAS researchers used nanotechnology to design a front planar lens that can be easily tailored and manufactured for different liquids with different refractive indices. The lens is made up of an array of titanium dioxide nanofins and fabricated using a single-step lithographic process.

"These lenses are made using a single layer of lithography, a technique widely used in industry," said Wei Ting Chen, first author of the paper and postdoctoral fellow at SEAS. "They can be mass-produced with existing foundry technology or nanoimprinting for cost-effective high-end immersion optics."

Using this process, the team designed metalenses that can not only be tailored for any immersion liquid but also for multiple layers of different refractive indices. This is especially important for imaging biological material, such as skin.

"Our immersion meta-lens can take into account the refractive indices of epidermis and dermis to focus light on the tissue under human skin without any additional design or fabrication complexity," said Alexander Zhu, coauthor of the paper and graduate student at SEAS.

"We foresee that immersion metalenses will find many uses not only in biological imaging but will enable entirely new applications and eventually outperform conventional lenses in existing markets," said Capasso.

Courtesy: ScienceDaily

   
Other News
Water forms `Spine of Hydration` around DNA
Mass-Producible Quantum Computers
Nanoscale Examination of a Living Cell Membrane
Insulating Nanomagnets Driven by Spin Torque
Water is surprisingly ordered on the nanoscale
Math, Biology and Nanotechnology
Energy Decay in Graphene Resonators
Oddball Enzyme to Build new Biomaterials out of DNA
Self-healing Battery Anodes
Nano Fiber feels forces, hears sounds
First `Nanotherapeutics` Drug Delivered to a Tumor
Precision Control using Magnetic Molecules
Anticancer Nanomaterials
New Computer Chips
Stretchable Hologram
Beautiful, Consistent Carbon Belts
Nanoscale Imaging
Subatomic Scale
Wood filter
Slingshot
`Hot` electrons
More Wfficient Catalytic Material Developed
New material changes to the environment
Record Resolution at a nanometer length scale
Exotic nanomaterials
Nanoparticles explaining risks to heart
Nanodiamond-enhanced MRI
Nano-notch
Single-molecule diode created
A novel form of iron for fortification of foods
WALK-IN-INTERVIEWs
Bonding Chips using Inkjet Printers
Nanoparticles helps Melanoma Treatment
Imaging at the Speed of Light
Reusable Sponge that Soaks up Oil
Color-Changing Glass
Molecular `Leaf`
Optical Metamaterial
Most Complex nanoparticles Designed
Low-Cost Diagnostic Systems
Ultralight Web of Silk Nano Fibers
shape-Shifting Molecular Robots
Magnetic `Persuasion` in Neighboring Metals
Anti-Fogging Water-Repellent Nanotextures
Portable Nanofiber
Resilient Flight Computers
Triboelectric nanogenerators
Nano `sandwich`
Computing with Biochemical Circuits made Easy
  Untitled Document
 
     
  Untitled Document
 
 
Untitled Document
  Follow us On  Follow us on FacebookFollow us on Twitter  
© 2010 Nano Digest. All Rights Reserved.   - Rify Hosting -