Spring Break
New technique creates 3-D holographic images
Issue date: 3/6/08
"Three-dimensional holographic imaging" is no longer just in the realm of Star Wars. Scientists at Hopkins and Ben-Gurion University in Israel have developed a technology that actually allows 3-D images to be taken on microscopic samples.
The technique is called FINCH, for Fresnel incoherent correlation holography. To create a holographic image, a photograph is taken of the interference between two beams of light. One is reflected from the object and the other is a uniform reference beam.
These two beams must be "coherent," or originate from the same laser. If the objects are illuminated by normal "incoherent" light, or if the sample itself emits fluorescent radiation, the current holographic techniques fail.
The basic principle of FINCH, however, takes advantage of this shortcoming and allows holograms to be generated from incoherent white light.
"If a beam is emerged from a single object point, and split to two beams, these two beams are mutually coherent to each other and can interfere," explained Joseph Rosen, co-inventor of the technique along with Gary Brooker. All of the interference patterns are then collected, generating the desired hologram.
Currently, holographic imaging can be performed, but multiple images must be taken and reconstructed to generate the hologram, which is often a time-consuming process. Additionally, it requires microscope objectives with low resolving power, which offer less detail, whereas the FINCH system uses microscope objectives with the highest resolution.
"The FINCH is the only method in general optical microscopy that captures the entire 3-D specimen without scanning the observed space," Rosen said.
It is the fastest available 3-D microscope, and it requires no moving parts. Thus, the FINCH can also be used to record and display holographic images of moving objects, including rapidly occurring cell processes, which cannot be done with traditional 3-D microscopes.
The development of this technique could revolutionize the use of holograms. "The FINCH opens the possibility to take holograms without lasers and in non-laboratory conditions," Rosen said. The principle FINCH uses can also be applied to any wave medium, such as X-rays or sound waves.
This technology even has the potential to allow for the development of holographic cameras, whereby users can simply take a 3-D snapshot of any scene. FINCH also has potential in the medical fields of ultrasounds, CT scans and X-rays, as well as security screening and photography.
Not only does the theory behind FINCH provide the opportunity for widespread use of holograms, but applications of the technology could become available to the public in the near future.
The technique is called FINCH, for Fresnel incoherent correlation holography. To create a holographic image, a photograph is taken of the interference between two beams of light. One is reflected from the object and the other is a uniform reference beam.
These two beams must be "coherent," or originate from the same laser. If the objects are illuminated by normal "incoherent" light, or if the sample itself emits fluorescent radiation, the current holographic techniques fail.
The basic principle of FINCH, however, takes advantage of this shortcoming and allows holograms to be generated from incoherent white light.
"If a beam is emerged from a single object point, and split to two beams, these two beams are mutually coherent to each other and can interfere," explained Joseph Rosen, co-inventor of the technique along with Gary Brooker. All of the interference patterns are then collected, generating the desired hologram.
Currently, holographic imaging can be performed, but multiple images must be taken and reconstructed to generate the hologram, which is often a time-consuming process. Additionally, it requires microscope objectives with low resolving power, which offer less detail, whereas the FINCH system uses microscope objectives with the highest resolution.
"The FINCH is the only method in general optical microscopy that captures the entire 3-D specimen without scanning the observed space," Rosen said.
It is the fastest available 3-D microscope, and it requires no moving parts. Thus, the FINCH can also be used to record and display holographic images of moving objects, including rapidly occurring cell processes, which cannot be done with traditional 3-D microscopes.
The development of this technique could revolutionize the use of holograms. "The FINCH opens the possibility to take holograms without lasers and in non-laboratory conditions," Rosen said. The principle FINCH uses can also be applied to any wave medium, such as X-rays or sound waves.
This technology even has the potential to allow for the development of holographic cameras, whereby users can simply take a 3-D snapshot of any scene. FINCH also has potential in the medical fields of ultrasounds, CT scans and X-rays, as well as security screening and photography.
Not only does the theory behind FINCH provide the opportunity for widespread use of holograms, but applications of the technology could become available to the public in the near future.
Be the first to comment on this story