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There is a fair amount of confusion caused by the reporting of dynamic range of beam profilers. The purpose of this applications note is to explain some of the terminology used in the discussion of this parameter by both Ophir- Spiricon and other suppliers of beam profilers.
 
Definition
Dynamic Range is the ratio of the largest measurable signal to the smallest measurable signal. The smallest measurable signal is typically defined as that equal to the noise level, or alternatively the “Noise...

The need to profile lasers with powers in the 10mW to 1W range are becoming more common. Many of these lasers are in the visible spectrum, allowing them to be measured with CCD and CMOS camera systems. As with any laser that is being measured with a camera array, the beam needs to be attenuated, but there are some cautions to be observed. These beams are not so powerful that they will damage or destroy typical absorptive filters. In fact, it is possible to stack up a sufficient optical density to reduce the power of a 1W laser to the nW...

By Allen Cary, Director of Marketing, Ophir-Spiricon

Measuring the propagation parameters of a laser beam is an important method of understanding the quality of the laser beam and predicting its performance for various laser applications. For this reason, it is one of the major specifications required by laser users and reported by laser manufacturers. Ophir-Spiricon has been a leader in providing instruments dedicated to this important measurement. There are currently three different instruments...

Dick Rieley, Mid-Altantic Regional Sales Manager, Ophir Photonics

By Dick Rieley, Mid-Altantic Regional Sales Manager, Ophir Photonics Group

A research organization was developing a critical procedure that required a pulsed DUV laser beam at 193nm. The current equipment only produced a gray-scale image that told little about the distribution of the energy intensity across the beam profile. The solution was a CCD camera-based profiler.

Background
The organization was developing a new...

By Allen M. Cary, Jeffrey L. Guttman, Razvan Chirita, Derrick W. Peterman, Photon Inc

A new instrument design allows the M² beam propagation ratio to be measured in real time at the update rate of a standard CCD camera. This allows lasers from single shot to CW to be measured while the laser cavities are being adjusted. This drastically reduces the test time required for this operation. In this paper we will discuss the theory behind this innovative approach to the M²...

John McCauley, Midwest Sales Manager, Ophir-­Spiricon

 

The New Year is a time to look back on the past year and contemplate how to do things better. It’s a time to make New Year’s resolutions in an effort to be a better person and do things better. One of the most common and popular New Year’s resolutions is the renewed commitment to losing weight. As many of us are all too familiar with, that means eating better and getting involved in a regular exercise routine. One of the...

By Gary Wagner, General Manager (U.S.), Ophir Photonics

W. Edwards Deming said, "If you can't measure it, you can't control it," and "You cannot inspect quality into the product; it is already there." Instead of trying to inspect-in quality, focus on adding value once you're assured that the previous process was done right and to specification.
 
Since the mid-1980's, tens of thousands of machine vision camera systems have been installed along...

By Gary Wagner, General Manager (U.S.), Ophir Photonics

A recent application called for the beam analysis of a 1550nm laser source with a challenging optical arrangement. Signal loss occurred at each beam transfer across multiple reflective surfaces. A more sensitive camera with Frame Summing was required to bring out the full beam pattern, size, and depth.
The 1550nm laser source was measured...
John McCauley, Product Specialist, Ophir-Spiricon

There is no doubt that the application of the fiber laser source has changed the way laser users look at the use of lasers. Fiber lasers are used in processes too numerous to count and people are discovering new uses every day.

We’ve heard for several years about the high quality beams that the fiber laser produces. Laser quality is usually defined by an M2 measurement. The closer the M2 measurement is to the value of 1, the better the “focusability” of the laser and, therefore, the higher...

By G.E. Slobodzian, Director of Engineering, Retired, Ophir-Spiricon

Part 1: New Camera Technologies

Part 2: Baseline Methods and Mode Effects

In Part 2, we demonstrated the need for employing an accurately computed baseline and retaining both the positive and...

By G.E. Slobodzian, Director of Engineering, Retired, Ophir-Spiricon

Methodology
Part 2 of this paper examines the effects of baseline caused errors in beam width measurements using the four most common methods for calculating a beam width:

  • D4σ, second moment
  • 13.5% of Peak, using the moving slit method
  • 86.5% encircled power smallest aperture (Power...
In 1997, Dr. Carlos Roundy, founder and president of Spiricon Inc., presented a paper at the 4th International Workshop on Lasers and Optics Characterization in Munich Germany. This paper was based on work that was carried out at Spiricon in the mid 90’s. At the time new insights were being presented on how to characterize a laser beam. Previous definitions were somewhat simplistic and most often were driven by customers telling us how they wanted the beam measured.

We recently came across an interesting customer problem, in which every time he disconnected the FO connector from the adapter (that is mounted on the sensor) and then reconnected it, the power read about 50-100 uW higher than it did (nothing else changed). It then took about 10 minutes to slowly come back down to what it had been. After an investigation, we found that the increase in reading when disconnecting/reconnecting the fiber connector is a thermal effect, and not a technical flaw in the unit. If you experience something like this,...

“The right tool for the right job” is a maxim many professionals use for selecting and using the correct tools for an exact application. Perhaps that is a good new year’s resolution if you do not already live by that rule. Ophir’s products are precision scientific instruments, with world-class acceptance, reliability, and accuracy. We seek to provide you the exact tool for your application and we help you maintain that tool for its lifetime. If you own a reliable sensor and meter that has lasted many years, we congratulate you for carefully protecting your...

Occasionally it is not possible to measure a laser system directly using StarLab. This can be because the laser system is in a controlled environment where a computer is unable to be installed. The Vega handheld meter can store up to 10 log files into its onboard memory containing up to 5,400 samples each for a total of 54,000 samples. Then the meter can be interfaced to a computer running StarLab to upload the files later.
Dick McCreary, Ohio Calibration Laboratories

The Ophir Nova or Laserstar series power meters, along with the appropriate photodiode sensors, comprise optical instrumentation we use on a daily basis for technical support and calibration of police lidar devices.

 
With ever increasing frequency, police agencies throughout the world are enjoying the pinpoint accuracy and reliability of laser-equipped lidar instruments for vehicle speed enforcement. Crime scene and vehicle crash...

I am a fifth year graduate student, working in the Saykally group at the University of California Berkeley. My research focuses on investigating air/water interfaces using second harmonic generation, a surface selective nonlinear optical technique. We are interested in investigating the microscopic structure of the air/water interface, as well as the effect of aqueous electrolytes on this interface. Our laser system includes a home built Ti:Sapphire oscillator and a commercial amplifier.
 
The oscillator can be a bit finicky...

Aligning an invisible laser beam with a visible pointer beam may sound simple but to do it right with everything lined up is not so obvious. Here is how it is done:

 

 

Measuring the power of scanning lasers, such bar code scanners, presents a problem. A bar code laser beam scans back and forth at a very high frequency so any ordinary photodiode power meter will not measure the power in the beam but rather the average power impinging on it, i.e. the power times the fraction of time the beam is on the detector. Therefore, when exposed to a scanned beam, the reading will be much lower than the actual power in the beam. For example, if a scanning laser delivers 2mW to a photodiode sensor and the beam is on the sensor only 1% of...

What happens when you have an application that requires a specific sensor with respect to technology and mechanical applications? You know that a standard Ophir sensor works, but you want to tweak the specification and mechanical size a little to fit your application. You call your Ophir representative and ask about OEM sensors.
 
Recently, a customer called and asked these exact questions. Knowing that Ophir has OEM prototypes available, the customer asked to evaluate the OEM thermal sensor 20C-UA. His power requirements at...

I am integrating a L100(500A) power meter head into a workstation and I would like to know how long between "readings" do I have to wait for the head to cool or what dictates how long I can shoot into the head. I realize that I can put a beam into the head at 500W for 1 min, 300W for 2 min or 75W continuously...but what determines how long I must wait if I wanted to take a 150W reading for 20 seconds, 10 times in a row (as an example)? How long would I have to wait between shots or could I take 5 readings, then wait 1 min and take 5 more etc.

The problem of irradiating...

Dr. Ephraim Greenfield CTO Ophir Optronics
  • Challenge: ever increasing demand for more accurate measurement
  • Solution: constant improvements in equipment and methods
  • How do we calibrate laser Power / Energy?
  • Basic method: stable laser and substitution
  • What is expected accuracy in simple case?

(power cal and wavelength available at NIST)

 

...

Mark Slutzki , Product Manager, Ophir Photonics

Confusion time…?

 
There seems to be a good deal of confusion when it comes to the terms “response time” and “integration time” of energy sensors. In this article we will clarify the meaning of these terms, as they apply to Ophir’s pyroelectric “Smart Sensors.”
 
Pyroelectric sensors use a pyroelectric crystal. When a laser pulse is absorbed, it is turned into a heat pulse in the crystal, and the crystal then generates an electric...

Julian Marsden, Hardware Team Manager, Ophir Photonics
The beauty of integrating an OEM sensor into your laser system is that you get to call the shots. What matters to you the most? Accuracy? Size? Output type? Tell us what you need and we’ll make it happen. Julian Marsden, the head of our electrical engineering department, wrote up a white paper to show you some of the OEM energy sensor options that are available...
There are two main technologies commonly used today for measuring laser beam powers:
  • Photodiode-based sensors, used for measuring low powers (from pW up to several hundred mW, typically); these are limited to spectral regions from the UV to the near IR, depending on the specific semiconductor used, and
  • Thermal sensors, used for measuring higher powers; the most sensitive thermal sensors can measure from as low as tens of microwatts, and up to 100 KW and beyond.
What if you need to measure very low power laser beams, say on the order of nanowatts, but with wavelengths in the mid or far IR region? This leaves you in a quandary...

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