Featured Research

from universities, journals, and other organizations

Picosecond Oscilloscope

Date:
May 30, 2009
Source:
Optical Society of America
Summary:
An oscilloscope is a device for displaying signals that are too fast to be seen by the human eye. Typically the signal consists of a voltage level that changes quickly moment by moment (over millisecond to nanosecond timescales). What is seen on the screen of the scope is a waveform whose value is graphed along the vertical axis as a function of the horizontal axis representing time. An electron beam, aimed at a phosphorescent screen, is swept horizontally providing a light-trace on the screen while, coincidentally, the instantaneous voltage of the input signal is used to deflect the electron beam up or down, creating the visible trace.

An oscilloscope is a device for displaying signals that are too fast to be seen by the human eye. Typically the signal consists of a voltage level that changes quickly moment by moment (over millisecond to nanosecond timescales). What is seen on the screen of the scope is a waveform whose value is graphed along the vertical axis as a function of the horizontal axis representing time. An electron beam, aimed at a phosphorescent screen, is swept horizontally providing a light-trace on the screen while, coincidentally, the instantaneous voltage of the input signal is used to deflect the electron beam up or down, creating the visible trace.

The dynamic range of this whole process is the range of voltage values that can be displayed; the other important feature is the time resolution: how fine a time scale can be achieved. Conventional analog television displays use comparable technology. A trace is swept horizontally across the screen, but instead of deflecting the beam up and down, the beam is interrupted or allowed to proceed toward the phosphor screen, where the trace shows up as a bright or dark spot. The display is then scanned across the screen again in a raster pattern to build up a complete screen image (but so quickly that the human eye doesn't notice it at a rate of 30 or 60 frames per second).

For performing high-end physics, ordinary oscilloscopes and televisions aren't fast enough, and the deflection of a beam used to display an image or a short-lived signal requires a different technology, which sometimes goes by the name "streak camera." Because the electrons comprising the beam are charged particles, the signals they carry suffer unavoidable blurring where the signal strength is strongest, thereby limiting the useful dynamic range. John Heebner and colleagues at Lawrence Livermore National Lab (LLNL) recently devised a solid-state all-optical streak camera, the first to attain a time resolution near 1 picosecond while simultaneously preserving a wide dynamic range, 3000:1. In his camera, the beam being deflected consists not of charged electrons but of uncharged photons, which do not suffer from the limitations of conventional streak cameras.

He achieves an unprecedented deflection rate of a light beam by sending it through an ordinary planar waveguide whose optical properties can be nearly instantaneously modified by a separate pump laser beam incident from above. A sequential array of "transient" prisms is created by first allowing the pump beam to pass through a serrated mask. When the pump beam is properly synchronized to the signal beam to be recorded, time-of-flight at the speed of light does the rest. Because later portions of the signal encounter more prisms, that part of the signal is deflected by a greater amount than the earlier portions of the signal that had already advanced through the waveguide before the prisms turned on. The prisms persist for the duration of the sweep and disappear in time for the process to start again with the next trace. Each deflected light trace is then focused onto an array of camera pixels. The light level detected on the array thus preserves a recording, over time, of the light beam's intensity.

Heebner's device, which he calls serrated light illumination for deflection encoded recording (or SLIDER), can even be used to study short bursts of light in the X-ray region of the light spectrum. This is accomplished by first encoding the X-ray signal onto an optical beam using an optical device (a Fabry-Perot cavity) that can be modulated at picosecond timescales. This makes SLIDER potentially valuable for monitoring the brilliant bursts of X-rays streaming from fusion targets at the collision point where the multiple laser beams of LLNL's National Ignition Facility (NIF) come together.

The benefit of the device is that it enables the recording of very fast phenomena. As the world's fastest light deflector, it can be used as a picosecond oscilloscope or for observing transient events like the miniature fusion reaction that occurs at the National Ignition Facility.

This research is scheduled to be presented during the 2009 Conference on Lasers and Electro-Optics/International Quantum Electronics Conference (CLEO/IQEC) May 31 to June 5 at the Baltimore Convention Center in Baltimore.


Story Source:

The above story is based on materials provided by Optical Society of America. Note: Materials may be edited for content and length.


Cite This Page:

Optical Society of America. "Picosecond Oscilloscope." ScienceDaily. ScienceDaily, 30 May 2009. <www.sciencedaily.com/releases/2009/05/090526163014.htm>.
Optical Society of America. (2009, May 30). Picosecond Oscilloscope. ScienceDaily. Retrieved October 21, 2014 from www.sciencedaily.com/releases/2009/05/090526163014.htm
Optical Society of America. "Picosecond Oscilloscope." ScienceDaily. www.sciencedaily.com/releases/2009/05/090526163014.htm (accessed October 21, 2014).

Share This



More Matter & Energy News

Tuesday, October 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Thanks, Marty McFly! Hoverboards Could Be Coming In 2015

Thanks, Marty McFly! Hoverboards Could Be Coming In 2015

Newsy (Oct. 21, 2014) If you've ever watched "Back to the Future Part II" and wanted to get your hands on a hoverboard, well, you might soon be in luck. Video provided by Newsy
Powered by NewsLook.com
Robots to Fly Planes Where Humans Can't

Robots to Fly Planes Where Humans Can't

Reuters - Innovations Video Online (Oct. 21, 2014) Researchers in South Korea are developing a robotic pilot that could potentially replace humans in the cockpit. Unlike drones and autopilot programs which are configured for specific aircraft, the robots' humanoid design will allow it to fly any type of plane with no additional sensors. Ben Gruber reports. Video provided by Reuters
Powered by NewsLook.com
Graphene Paint Offers Rust-Free Future

Graphene Paint Offers Rust-Free Future

Reuters - Innovations Video Online (Oct. 21, 2014) British scientists have developed a prototype graphene paint that can make coatings which are resistant to liquids, gases, and chemicals. The team says the paint could have a variety of uses, from stopping ships rusting to keeping food fresher for longer. Jim Drury reports. Video provided by Reuters
Powered by NewsLook.com
China Airlines Swanky New Plane

China Airlines Swanky New Plane

Buzz60 (Oct. 21, 2014) China Airlines debuted their new Boeing 777, and it's more like a swanky hotel bar than an airplane. Enjoy high-tea, a coffee bar, and a full service bar with cocktails and spirits, and lie-flat in your reclining seats. Sean Dowling (@SeanDowlingTV) has the details. Video provided by Buzz60
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins