The mirror chip can activate a handheld microscope with a dark field, Dark field microscopy can reveal the intricate details of translucent cells and aquatic organisms as well as faceted diamonds and other gemstones which would otherwise look very pale or even not visible under ordinary light field microscopy.
The scientists made dark field images by installing standard microscopes with often expensive components to illuminate the sample table with hollow cones, very angular light.
When a translucent sample is placed under a dark field microscope, the light cone is scattered by the sample property to produce a sample image on a microscope camera that contrasts strongly with a dark background. The mirror chip can activate a handheld microscope with a dark field.
MIT engineers have now developed a small mirror chip that can be used to produce dark field images without very expensive components.
The chip is slightly larger than a stamp and as thin as a credit card. On a microscope table, the chip emits hollow light cones with which detailed images of algae, bacteria and similar translucent miniature objects can be made in the dark field.
The new optical chip can be added to standard microscopes as a cheap and reduced alternative to conventional dark field components. This chip can also be mounted on a handheld microscope to take pictures of microorganisms in the field. The mirror chip can activate a handheld microscope with a dark field.
Structural colors can be seen on the wings of dense beetles and butterflies, bird feathers and fish flakes and some petals.
Inspired by examples of structural colors in nature, Colle researched various ways to manipulate light from a microscopic and structural perspective.
As part of this effort, he and Chazot designed a small three-layer chip that they originally wanted to use as a mini laser. The middle layer serves as a light source for chips made of polymers that are impregnated with quantum dots of tiny nanoparticles that emit light when excited by fluorescent light.
Chazot compared this layer with a glitter bracelet in which the reaction of two chemicals produces light. except that no chemical reaction is needed here, only a little blue light makes the quantum dots glow bright orange and red. The mirror chip can activate a handheld microscope with a dark field.
The researchers placed the Bragg mirror structure made of nanoscale layers of transparent material with a clear refractive index, ie the extent to which these layers reflect the light that occurs, above this light-producing layer.
The researchers added a third feature under the light-producing layer to recycle the photons that were originally removed by the Bragg mirror. This third layer consists of a transparent, dense epoxy layer, which is covered with reflective gold paper and looks like a mini egg crate, which is filled with a small recess with a diameter of about 4 micrometers each. The mirror chip can activate a handheld microscope with a dark field.
Chazot covered this surface with a thin layer of gold that was highly reflective – an optical arrangement that captured light reflected from the Bragg mirror, and ping-pong which tended to reflect back at a new angle that I missed. This third layer design was inspired by the microscopic scale structure on the Papilio butterfly’s wing.
Butterfly wing scales have a very interesting structure that resembles an egg shaped Bragg mirror and gives them a colorful color.
First, the researchers developed the chip as an array of mini laser sources and thought that the three layers could work together to create a customized laser emission pattern.
The original project was to build a double cavity assembly that could be moved individually at a micro scale.
Chazot and his colleagues used an established theoretical optical concept to model the optical properties of a chip and optimize its performance for this newly discovered task. They make many chips, each of which creates a hollow cone of light with a suitable angular profile. The mirror chip can activate a handheld microscope with a dark field.
To test the chip, the team collected samples of seawater and non-pathogenic E. coli strains and placed each sample on the chip with a standard light field microscope, which they placed on the platform. With this simple structure, they can produce clear and detailed images in the dark fields of individual bacterial cells and microorganisms in seawater that are almost invisible under bright field lighting.
Kohl said that this darkfield illumination chip could be mass produced in the near future and was even installed on a simple middle school microscope to display low contrast and translucent biological samples.
In combination with other work in Colle’s laboratories, the chip can also be embedded in a small dark-field imaging device for on-site diagnostics and bioanalytic applications.
If we can assign a surface control piece to the surface that you can attach to a microscope as a media sample, dark field images are a very affordable choice in a number of imaging scenarios, the researchers say.