New version of green laser up and running
A new and improved version of a light-tracking laser was placed on top of the Science Research building the summer of 2010, beaming a green light on clear nights, and was most recently used Feb. 3.
The laser is known as LIDAR – Laser Imaging Detection and Ranging system. It will soon be the most sensitive LIDAR in the world, and is meant to gauge the rate of photons returning from the atmosphere in relationship with molecules in the sky, said physics professor Vince Wickwar.
“It’s fun to see the laser going off, and to be this close to the research,” said physics major Lance Peterson, who is using the LIDAR for his graduate thesis and will be presenting the information behind the laser to schools in Ithaca, N.Y., in late March.
Peterson said he isn’t yet sure when the laser will officially qualify as the most sensitive LIDAR in the world because he is uncertain when it will become fully operational in being able to completely process its data.
Activating just one laser costs at least $100,000, said Marcus Bingham, a physics junior who has also been heavily involved in the project.
While the LIDAR can extend 55 miles, only one-and-a-half miles of its extension could be viewed from the ground on Thursday before being blocked by cloud coverage, Peterson said.
LIDAR functions by measuring how far photons are released into the atmosphere before hitting molecules that essentially act as walls, sending the photons back where they came. Some photons will rise higher than others before coming into contact with a thinner concentration of molecules and coming back to Earth.
The photons will then glance off mirrors and travel into a fiber-optic cable which will then pass through what Peterson called a “chopper.” The light being divided is then prepared to enter into a monitor called photomultiplier tube housing (PMT), which sends the information of how the photons act with the molecules.
Wickwar said the LIDAR beats 30 times per second, and Peterson said because of the rapidity of the light, one would go blind if they stared directly at it for even one-thirtieth of a second.
According to Wickwar, USU’s physics department owned a laser with significantly less sensitivity from 1993-2004. Cache Valley residents had the opportunity to witness the laser 900 times for 5,000 combined hours during those 11 years. However, organizations such as the National Science Foundation (NSF) stopped providing grants as the primary funding for the laser, and the work done on the tool came to a hiatus.
But Wickwar continued to relentlessly contact grant agencies for support to bring LIDAR back. His efforts formally succeeded when the new laser was unveiled at an Oct. 29 Halloween event hosted by the College of Science.
NSF was among the agencies who provided funding beginning last year. The minimum amount of grants were still in excess of $250,000.
The process of resurrecting a greater version of the LIDAR began in June, when Peterson was simply looking for work. He applied for a position to do field work with a professor in his major. He began the job search after working with sprites and halos with faculty member Mike Taylor, also in the physics department, but the department ran out of funding.
“Dr. Wickwar had more money and wanted a student,” Peterson said.
He, Wickwar and Bingham began the research with a degree of faith, not certain they could start the LIDAR once again.
“It was just something that sounded interesting to me,” Peterson said. “It’s my favorite project so far. It’s more hands-on, rather than just analyzing data. This has been a lot of real-world work.”
One of the unique features of the laser, Peterson said, is the fact that you can place your hand through the shaft of light and actually feel the light. Not the heat of the light, he insisted, but the power of the light itself. Doing so results in a loud pop and a minor light explosion due to the intensity of molecules being detected from the hand at once.
“It’s the only time I’ve ever actually felt light,” Peterson said. “You can normally feel sunlight, but this time the light actually hit me. I think it’s just amazing.”
Wickwar said this time around, the LIDAR contains four mirrors rather than the one which the laser of 11 years previous had. For this reason, it will exceed the previous USU LIDAR by 30 times in collecting area, resulting in a sensitivity 70 times as strong.
“Anytime you can change a sensitivity by 10, that’s a big deal, and we’re doing it by about 70,” Wickwar said.
It will also top the current world record-holder for most sensitive LIDAR, found at the University of Ontario. In fact, one of the professors who is primarily responsible for operating their LIDAR began his associate teaching career at Utah State, under Wickwar.
It’s an accomplishment the professor said he is proud to be a part of, particularly after having seen the rise and fall of the previous laser.
“It’s great. We were jumping for joy,” said Wickwar in regards to being able to unleash the LIDAR for the first time since returning to the physics department. “We are part of quite a project once again.”
– rhett.wilkinson@aggiemail.usu.edu