A device that radically simplifies the operation of 鈥渓aser traps鈥� could let non-experts manipulate microscopic objects more easily. It could provide new research opportunities for biologists and other scientists without expertise in optics, the system鈥檚 designers claim.
Until now, experts have had to painstakingly adjust the position of individual mirrors to create laser beam 鈥渢raps鈥� that hold cells or small particles in place.
The new device, created by Danish researchers, provides a simple 鈥渄rag and drop鈥� interface that makes this process far simpler.
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(2.5MB .mov format). Up to 80 objects can be manipulated at a time, using the device.
鈥淲e hope to open up the technology to a wider audience 鈥� biologists in particular,鈥� says Jesper Gl眉ckstad, of the Ris酶 National Laboratory in Denmark. Gl眉ckstad notes that it takes considerable skill to position a sample and the mirrors needed to align the beams: 鈥淚t has been a bottleneck until now 鈥� only a few people in my own group are able to do it within a reasonable time.鈥�
In the crosshair
The new device has a small motor fitted to each of its mirrors, which are controlled by a computer. A video display shows a crosshair pinpointing the focus of one of two laser beams. The user drags this across the screen to position each of the beams so that they are precisely aligned.
Once this set of laser crosshairs have been positioned correctly, up to 80 cells or particles can be manipulated in 3D simultaneously using another drag and drop interface. This involves tuning the power and other optical properties of each of the beam pairs.
Other, simpler laser tweezers can hold a cell in place under a microscope but such tweezers use only a single beam. The lens must be positioned about one millimetre from a sample.
Larger workspace
This 鈥渋s like sticking your nose right down to the surface鈥�, says Gl眉ckstad, 鈥測ou get tunnel vision.鈥� By contrast, counter-balancing two beams extends the gap between lens and sample to one centimetre, providing a larger workspace, he adds.
David McGloin, who works on laser trapping at St Andrews University, UK, says most researchers currently build their own laser manipulation systems. 鈥淭here is certainly the opportunity for greater penetration of the technology among biologists without that expertise,鈥� he told New 杏吧原创.
Gl眉ckstad and colleagues plan to develop their drag and drop system commercially, but McGloin points out that there will still be alternatives to buying an expensive off-the-shelf system. 鈥淚n a research sector like universities there is often the possibility to find collaborators that do have optics expertise,鈥� he notes.
Journal reference Optics Express (vol 15, p1923)
