Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Novel power meter opens the door for in-situ, real-time monitoring of high-power lasers

30.05.2018

NIST researchers have developed a compact, high-accuracy, point-of-use high-power laser power meter in the form of a folding mirror called 'Smart Mirror,' making in-situ, real-time measurement of laser power possible

High-power lasers are now widely used in additive manufacturing and laser welding systems to precisely cut and weld metal, making all kinds of metal parts for medical devices, aerospace applications, automotive industries, and more.


This mirror is a force scale that relates the force of a laser shining on it to the power (i.e., the brightness) of that laser. Scientists at NIST are developing these devices to embed into laser-based manufacturing tools for improved performance and reliability. The device in this picture is a prototype of their capacitive pressure sensor designed to measure 1,000 W lasers in the infrared with better than 1% uncertainty. The next phase of devices like this one will be standard reference instruments that report absolute power of any color laser from 1 mW up to 100 kW of power.

Credit: A. Artusio-Glimpse/NIST >alexandra.artusio-glimpse@nist.gov<

With the rise in industrial use of high-power laser processing, manufacturers increasingly seek high-accuracy, point-of-use laser power meters that can quickly report laser powers at any time in the manufacturing process -- a vital aspect to controlling product quality.

Traditional laser power meters, however, are often bulky in size and slow in response time. Power measurements can also only be taken separately, interrupting the manufacturing process.

Now, a group of researchers from National Institute of Standards and Technology (NIST) in Boulder, Colorado, have developed a smaller, faster and more sensitive laser power meter in the form of a folding mirror they call a "smart mirror."

The novel design uses a capacitor-based force transducer and merges optical elements, namely a high reflectivity mirror, and sensing elements into a compact cube package. The four-centimeter-on-a-side cubes can be conveniently embedded into laser optical systems or laser-welding systems for point-of-use, real-time laser power measurement and calibration. The researchers will present their innovation at the OSA Imaging and Applied Optics Congress, being held June 25-28 in Orlando, Florida, United States.

"Measuring laser power by measuring the pressure of a laser beam hitting a mirror is a very unique technique, [and] so far it is the only laser power measurement technique that is truly an in-situ process," said Alexandera B. Artusio-Glimpse, a scientist of NIST in Boulder, Colorado, and the primary author. "Unlike any other optical power measurement techniques, our method allows us to continue using the laser for work while a measurement is being taken."

Artusio-Glimpse explained that traditional high-power meters measure laser power by absorbing all the energy of a laser beam as heat and measuring the temperature change. The calorimetric measurement has to temporarily stop the laser beam from work for around tens of minutes.

"Using our 'Smart Mirror' laser power meter, that stop-measure-continue process is no longer needed. Manufacturers can measure the laser power continuously during every weld and monitor the laser calibration in real time, they would know right away whenever the laser has a problem and wouldn't risk wasting metal parts with bad welds," Artusio-Glimpse said.

The Smart Mirror laser power meter is also referred to as a radiation pressure power meter (RPPM), as the operating principle of this meter is based on measuring the pressure of the laser, the radiation pressure. Light has no mass, but it has momentum and when a laser beam strikes an object such as a mirror, it will exert a tiny force known as the radiation pressure on the mirror, which directly relates to the laser power. 200 watts of laser power, for example, exerts a force equivalent to 100 micrograms, which is roughly the weight of a single human eyelash.

The key part of the Smart Mirror design is a capacitor-based compact force transducer. It consists of a spiral planar silicon spring supporting a circular plate with a high reflectivity mirror on one side and an electrode on the other. An identical silicon spring with an electrode is placed close to the first spring such that the two electrodes face each other, forming a variable capacitor.

A laser beam reflecting off the mirror on the first spring will push the first spring to move toward the second and change the capacitance between the two electrodes. By comparing to a fixed reference capacitor, the researchers can calculate the radiation pressure and laser power. After reflecting off the mirror, the laser beam can be used directly for work, making real-time monitoring of laser power or laser calibration possible.

According to Artusio-Glimpse, the team has been developing the novel radiation pressure power meter for years and an earlier version of RPPM employed a commercially available scale with a mirrored surface as a force transducer. The final system was about the size of a shoebox, with a measurement sensitivity of 50 micrograms and response time of five seconds.

In the new version of the Smart Mirror, the researchers improved the measurement sensitivity by 100 times and decreased the response time by 50 times. They also mitigated static sagging errors of the device caused by gravity when the device is rotated. This allows the sensor to be embedded at the end of a robotic arm or in additive manufacturing and laser welding systems where the laser head will move and rotate -- a key feature that the early version bulk RPPM lacks. It also meets the measurement requirements of many commercially significant applications.

Based on preliminary tests, the new meter is sensitive enough to measure 100 watts of laser power with no more than one percent uncertainty, and with a response time faster than any other absolute high-power laser meter. The researchers are now continuing to validate these results with more tests. Artusio-Glimpse said the NIST team expects to establish a primary standard version of the Smart Mirror laser power meter in the near future.

Hear from the research team: ATh2A.2 "Non-Absorbing, Point-of-Use, High-Power Laser Power Meter," by Alexandra B. Artusio-Glimpse, Ivan Ryger, Paul Williams and John Lehman, at 10:30 am on June 28, 2018, at the Wyndham Orlando Resort International Drive, Orlando, Florida, United States.

###

MEDIA REGISTRATION: Media/analyst registration for the OSA Imaging and Applied Optics Conference 2018 can be accessed online. Further information is available on the event website, including travel details.

ABOUT OSA IMAGING AND APPLIED OPTICS CONGRESS

Imaging and Applied Optics Congress provides a comprehensive view of the latest developments in imaging and applied optical sciences, covering the forefront advances in imaging and applied optics as well as the application of these technologies to important industrial, military and medical challenges. The scope of the research presented in ranges from fundamental research to applied. General Chair for the 2018 Congress is Gisele Bennett, Florida Institute of Technology, USA.

Media Contact

Azalea Coste
acoste@osa.org
202-416-1435

 @opticalsociety

http://www.osa.org 

Azalea Coste | EurekAlert!
Further information:
https://www.osa.org/en-us/about_osa/newsroom/news_releases/2018/novel_power_meter_opens_the_door_for_in-situ_real

More articles from Physics and Astronomy:

nachricht Return of the Blob: Surprise link found to edge turbulence in fusion plasma
27.05.2020 | DOE/Princeton Plasma Physics Laboratory

nachricht NIST researchers boost microwave signal stability a hundredfold
26.05.2020 | National Institute of Standards and Technology (NIST)

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Biotechnology: Triggered by light, a novel way to switch on an enzyme

In living cells, enzymes drive biochemical metabolic processes enabling reactions to take place efficiently. It is this very ability which allows them to be used as catalysts in biotechnology, for example to create chemical products such as pharmaceutics. Researchers now identified an enzyme that, when illuminated with blue light, becomes catalytically active and initiates a reaction that was previously unknown in enzymatics. The study was published in "Nature Communications".

Enzymes: they are the central drivers for biochemical metabolic processes in every living cell, enabling reactions to take place efficiently. It is this very...

Im Focus: New double-contrast technique picks up small tumors on MRI

Early detection of tumors is extremely important in treating cancer. A new technique developed by researchers at the University of California, Davis offers a significant advance in using magnetic resonance imaging to pick out even very small tumors from normal tissue. The work is published May 25 in the journal Nature Nanotechnology.

researchers at the University of California, Davis offers a significant advance in using magnetic resonance imaging to pick out even very small tumors from...

Im Focus: I-call - When microimplants communicate with each other / Innovation driver digitization - "Smart Health“

Microelectronics as a key technology enables numerous innovations in the field of intelligent medical technology. The Fraunhofer Institute for Biomedical Engineering IBMT coordinates the BMBF cooperative project "I-call" realizing the first electronic system for ultrasound-based, safe and interference-resistant data transmission between implants in the human body.

When microelectronic systems are used for medical applications, they have to meet high requirements in terms of biocompatibility, reliability, energy...

Im Focus: When predictions of theoretical chemists become reality

Thomas Heine, Professor of Theoretical Chemistry at TU Dresden, together with his team, first predicted a topological 2D polymer in 2019. Only one year later, an international team led by Italian researchers was able to synthesize these materials and experimentally prove their topological properties. For the renowned journal Nature Materials, this was the occasion to invite Thomas Heine to a News and Views article, which was published this week. Under the title "Making 2D Topological Polymers a reality" Prof. Heine describes how his theory became a reality.

Ultrathin materials are extremely interesting as building blocks for next generation nano electronic devices, as it is much easier to make circuits and other...

Im Focus: Rolling into the deep

Scientists took a leukocyte as the blueprint and developed a microrobot that has the size, shape and moving capabilities of a white blood cell. Simulating a blood vessel in a laboratory setting, they succeeded in magnetically navigating the ball-shaped microroller through this dynamic and dense environment. The drug-delivery vehicle withstood the simulated blood flow, pushing the developments in targeted drug delivery a step further: inside the body, there is no better access route to all tissues and organs than the circulatory system. A robot that could actually travel through this finely woven web would revolutionize the minimally-invasive treatment of illnesses.

A team of scientists from the Max Planck Institute for Intelligent Systems (MPI-IS) in Stuttgart invented a tiny microrobot that resembles a white blood cell...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Dresden Nexus Conference 2020: Same Time, Virtual Format, Registration Opened

19.05.2020 | Event News

Aachen Machine Tool Colloquium AWK'21 will take place on June 10 and 11, 2021

07.04.2020 | Event News

International Coral Reef Symposium in Bremen Postponed by a Year

06.04.2020 | Event News

 
Latest News

New 5G switch provides 50 times more energy efficiency than currently exists

27.05.2020 | Information Technology

Return of the Blob: Surprise link found to edge turbulence in fusion plasma

27.05.2020 | Physics and Astronomy

Upwards with the “bubble shuttle”: How sea floor microbes get involved with methane reduction in the water column

27.05.2020 | Earth Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>