Australian researchers have demonstrated a quantum microscope that can break through a fundamental barrier faced by regular microscopes and see tiny structures that are normally invisible. The device “squeezes” light to snap images with far greater clarity.
Optical microscopes work by beaming light onto a sample, but the photons in that light can be inherently random, creating noise in the images. The simplest way around that is to crank up the intensity of the light source, increasing the number of photons, but at a certain point that bright light begins to harm the sample, particularly when imaging live cells and microorganisms.
That creates a fundamental limit on resolution and sensitivity. But now, researchers at the University of Queensland have found a way to bypass that limit, by tapping into the spooky world of quantum physics.
The new microscope uses two laser light sources, one of which is rerouted through a potassium titanyl phosphate crystal. Essentially, that creates quantum correlations between pairs of photons in the light beam, letting them return more information about the sample than “regular” photons. The end result is higher-resolution images from lower intensities of light.
“The best light microscopes use bright lasers that are billions of times brighter than the Sun,” says Warwick Bowen, lead author of the study. “Fragile biological systems like a human cell can only survive a short time in them and this is a major roadblock. The quantum entanglement in our microscope provides 35 percent improved clarity without destroying the cell, allowing us to see minute biological structures that would otherwise be invisible.”
The team tested the technique on yeast cells, and were able to see tiny structures like the cell membrane, cytosol (the liquid inside the cell), and organelles. All of these appeared with far more clarity than most microscopes are capable of.
As intriguing as the technology is, there’s still plenty of room for improvement. The gain itself is fairly modest, the team says, and the technique is still relatively inefficient, but with further work these can be boosted by an order of magnitude.
The research was published in the journal Nature.
Source: University of Queensland