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| Debut for world's fastest camera | Debut for world's fastest camera |
| (about 5 hours later) | |
| The fastest imaging system ever devised has been demonstrated by researchers reporting in the journal Nature. | The fastest imaging system ever devised has been demonstrated by researchers reporting in the journal Nature. |
| Their camera snaps images less than a half a billionth of a second long, capturing over six million of them in a second continuously. | Their camera snaps images less than a half a billionth of a second long, capturing over six million of them in a second continuously. |
| It works by using a fast laser pulse dispersed in space and then stretched in time and detected electronically. | It works by using a fast laser pulse dispersed in space and then stretched in time and detected electronically. |
| The approach will be instrumental in analysing, for example, flowing blood samples in a search for diseased cells. | The approach will be instrumental in analysing, for example, flowing blood samples in a search for diseased cells. |
| What is more, the camera works with just one detector, rather than the millions in a typical digital camera. | What is more, the camera works with just one detector, rather than the millions in a typical digital camera. |
| Gathering steam | Gathering steam |
| Dubbed Serial Time-Encoded Amplified imaging, or Steam, the technique depends on carefully manipulating so-called "supercontinuum" laser pulses. | Dubbed Serial Time-Encoded Amplified imaging, or Steam, the technique depends on carefully manipulating so-called "supercontinuum" laser pulses. |
| These pulses, less than a millionth of a millionth of a second long, contain an enormously broad range of colours. | These pulses, less than a millionth of a millionth of a second long, contain an enormously broad range of colours. |
| Two optical elements spread the pinprick laser pulses into an ordered two-dimensional array of colours. | Two optical elements spread the pinprick laser pulses into an ordered two-dimensional array of colours. |
| It is this "2-D rainbow" that illuminates a sample. Part of the rainbow is reflected by the sample - depending on light and dark areas of the illuminated spot - and the reflections travel back along their initial path. | It is this "2-D rainbow" that illuminates a sample. Part of the rainbow is reflected by the sample - depending on light and dark areas of the illuminated spot - and the reflections travel back along their initial path. |
| Because the spreading of the pulse's various colours is so regular and ordered, the range of colours reflected contains detailed spatial information about the sample. | Because the spreading of the pulse's various colours is so regular and ordered, the range of colours reflected contains detailed spatial information about the sample. |
| "Bright spots reflect their assigned wavelength but dark ones don't," explained Bahram Jalali, the University of California, Los Angeles professor who led the research. | "Bright spots reflect their assigned wavelength but dark ones don't," explained Bahram Jalali, the University of California, Los Angeles professor who led the research. |
| Our next step is to improve the spatial resolution so we can take crystal clear pictures of the inner structure of cells Bahram Jalali, UCLA | Our next step is to improve the spatial resolution so we can take crystal clear pictures of the inner structure of cells Bahram Jalali, UCLA |
| "When the 2-D rainbow reflects from the object, the image is copied onto the colour spectrum of the pulse." | "When the 2-D rainbow reflects from the object, the image is copied onto the colour spectrum of the pulse." |
| The pulse then passes back through the dispersive optics and again becomes a pinprick of light, with the image tucked away within as a series of distributed colours. | The pulse then passes back through the dispersive optics and again becomes a pinprick of light, with the image tucked away within as a series of distributed colours. |
| However, that colour spectrum is mixed up in an exceptionally short pulse of light that would be impossible to unpick in traditional electronics. | However, that colour spectrum is mixed up in an exceptionally short pulse of light that would be impossible to unpick in traditional electronics. |
| The team then routes the pulse into a so-called dispersive fibre - a fibre-optic cable that has a different speed limit for different colours of light. | The team then routes the pulse into a so-called dispersive fibre - a fibre-optic cable that has a different speed limit for different colours of light. |
| As a result, the red part of the spectrum races ahead of the blue part as the pulse travels along the fibre. | As a result, the red part of the spectrum races ahead of the blue part as the pulse travels along the fibre. |
| Eventually, the red part and blue part separate in the fibre, arriving at very different times at the fibre's end. | Eventually, the red part and blue part separate in the fibre, arriving at very different times at the fibre's end. |
| All that remains is to detect the light as it pops out of the fibre with a standard photodiode and digitise it, assigning the parts of the pulse that arrive at different times to different points in two-dimensional space. | All that remains is to detect the light as it pops out of the fibre with a standard photodiode and digitise it, assigning the parts of the pulse that arrive at different times to different points in two-dimensional space. |
| The result of all this optical trickery: an image that represents a snapshot just 440 trillionths of a second long. | The result of all this optical trickery: an image that represents a snapshot just 440 trillionths of a second long. |
| The researchers used a laser that fired more than six million pulses in a second, resulting in as many images. However, they say that the system can be improved to acquire more than 10 million images per second - more than 200,000 times faster than a standard video camera. | The researchers used a laser that fired more than six million pulses in a second, resulting in as many images. However, they say that the system can be improved to acquire more than 10 million images per second - more than 200,000 times faster than a standard video camera. |
| 'Rogue cells' | 'Rogue cells' |
| Instead of the millions of detectors in a digital camera, Steam uses just one | Instead of the millions of detectors in a digital camera, Steam uses just one |
| While other cameras used in scientific research can capture shorter-lived images, they can only capture about eight images, and have to be triggered to do so for a given event. | While other cameras used in scientific research can capture shorter-lived images, they can only capture about eight images, and have to be triggered to do so for a given event. |
| The Steam camera, by contrast, can capture images continuously, making it ideal for random events that cannot be triggered. | The Steam camera, by contrast, can capture images continuously, making it ideal for random events that cannot be triggered. |
| Some applications that may benefit from the approach include observing the communication between cells, or the activity of neurons. | Some applications that may benefit from the approach include observing the communication between cells, or the activity of neurons. |
| But the perfect example of an application for the Steam camera's specifications is analysing flowing blood samples. | But the perfect example of an application for the Steam camera's specifications is analysing flowing blood samples. |
| Because the imaging of individual cells in a volume of blood is impossible for current cameras, a small random sample is taken and those few cells are imaged manually with a microscope. | Because the imaging of individual cells in a volume of blood is impossible for current cameras, a small random sample is taken and those few cells are imaged manually with a microscope. |
| "But, what if you needed to detect the presence of very rare cells that, although few in number, signify early stages of a disease?," asks Keisuke Goda, lead author of the study. | |
| Dr Goda cites circulating tumour cells as a perfect example of such a target. Precursors to metastasis, they may exist as only a few among a billion healthy cells. | |
| "The chance that one of these cells will happen to be on the small sample of blood viewed under a microscope is virtually negligible." | "The chance that one of these cells will happen to be on the small sample of blood viewed under a microscope is virtually negligible." |
| But with the Steam camera, fast-flowing cells can be individually imaged. | But with the Steam camera, fast-flowing cells can be individually imaged. |
| The team is working to extend the technique to 3-D imaging with the same time resolution, and to increase the effective number of "pixels" in a given image to 100,000. | The team is working to extend the technique to 3-D imaging with the same time resolution, and to increase the effective number of "pixels" in a given image to 100,000. |
| "Our next step is to improve the spatial resolution so we can take crystal clear pictures of the inner structure of cells," Professor Jalali told BBC News. | "Our next step is to improve the spatial resolution so we can take crystal clear pictures of the inner structure of cells," Professor Jalali told BBC News. |
| "We are not there yet, but if we are able to accomplish this, then there is no shortage of applications in biology." | "We are not there yet, but if we are able to accomplish this, then there is no shortage of applications in biology." |