Measuring optical signals in the femtowatt (10-15) to nanowatt (10-9) range can be a daunting task. Signal levels this low are lost in typical detector noise levels and swamped by background light. The noise floor for photodiode detectors operated with a small bandwidth (~10 Hz) is on the order of 1 picowatt (10-12). Further narrowing of the bandwidth by filtering or averaging will only provide a small additional reduction in the noise level....
Articles
19th century British physicist and engineer William Thomson, 1st Baron Kelvin, was the first to say, “If you can’t measure it, you
can’t improve it.” When applying this principle to improving laser-based processes, there are a variety of parameters that must be
measured. Given the continuously rising power of laser systems in material processing, the requirements for measurement
systems are more challenging than ever. Which technologies are available to measure high-power lasers? How often should they
be measured? What measurements should be tracked? When this data is collected, what should be done with it?
Each sensor from Ophir includes a performance specification datasheet but not a user manual. This datasheet lists operational parameters for the sensor, including items such as spectral range, power range, aperture size, accuracy specification, etc. Copies of these datasheets for current sensors are available on the website by clicking on the “Specifications” tab of the sensor's product page...
Often we get requests for the Total Optical Path Length when beam splitters are used on our line of 4.5 mm recessed CCD cameras. For a common setup using beam splitters P/N SPZ17015 and either one or two P/N SPZ17026 here are the Total Optical Path Length and a couple of pictures showing the layout. Length 2 (From first beam splitter to second beam splitter) Length 3 (From second beam splitter to third beam splitter) Total Optical Path Length with 2 beam splitters Total Optical Path Length with 3 beam splitters...
| The selection of an appropriate sensor to measure the power of a laser seems to be a simple and straightforward process. The sensor technology doesn’t seem to be too complex, the physical setup of the sensor seems easy enough. Yet, more often than not, the sensor turns out to NOT be the right one. As a result, inaccurate measurements are obtained, the sensor exhibits premature failure, and costly full disc replacement and recalibration are required. |
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Introduction
| An integrating sphere collects electromagnetic radiation from a source usually external to the optical device, usually for flux measurement or optical attenuation. Radiation introduced into an integrating sphere strikes the reflective walls and undergoes multiple diffuse reflections. After numerous reflections, the radiation is dispersed highly uniformly at the sphere walls. The resulting integrated radiation level is directly proportional to the initial radiation level... |
Small beams are used in many critical applications yet often they are not directly profiled. While obtaining good beam profiling data on beams under 10 μm has its challenges, they can be overcome with proven techniques.
Profiling beams under 10 μm in size is one of the more challenging beam profiling applications. There are numerous reasons for this, including the very small size. Focal plane arrays commonly used in beam profiling have pixel dimensions of 3 to 10 μm, which are too large to reasonably profile...
Introduction
Ophir Pyroelectric Energy Sensors and Photodiode Energy Sensors can measure pulse energy from pico-Joules to 10's of Joules, and up to 25kHz pulse rates. They support pulse widths from nanoseconds or below, up to 20ms. They are compatible with most Ophir Meters and PC Interfaces, including the Nova II, Vega, StarLite, StarBright, Centauri, Juno and EA-1 meters.
Most of the time, measurements in digital format are adequate, either in the form of measurements displayed on a screen, or data logged...
Problem: The “What’s This” feature only opens to the first page of the manual in Adobe Ready XI.
Solution...
Solution...
With the introduction of BeamGage the capability of using the built in photodiode trigger in the SP camera series is now available. However, some customers may not know how to use it or that they even had this capability.
With the recently released BeamGage version 5.4 this capability is now available. Some cameras may need to have their firmware upgraded where others just need to update to the latest version of BeamGage. To see if your camera has the latest firmware make sure you are using BeamGage 5.4 and connect your camera to the computer. Launch BeamGage and when it...
Ophir water cooled sensors are designed to measure high powers in a relatively compact package. In order for the sensor to operate properly, the water flow rate, temperature and temperature stability have to be in the right range. For best performance of the sensor, the water flow rate should be the recommended rate. If the user system is not able to reach the recommended rate, then the minimum rate can be used and the sensor will meet spec but there may be some degradation of response time and linearity...
The scientific community is often faced with the requirement of testing, validating, or merely qualifying several laser sources planned for a particular project.. Such testing is needed to:
- Ensure the laser source is performing up to the manufacturer’s specification
- Diagnose the quality and measurement aspect of the resulting beam
- Establish a baseline of the laser’s performance to be used against future measurements to determine if the laser has degraded or otherwise shifted in its performance.
This task puts a financial...
Ophir Photonics offers a number of solutions for profiling UV laser beams. Spot sizes from 0.15mm to over 25mm can be safely profiled without the risk of camera sensor damage or degradation. Laser beam analyzer accessories based on wavelength conversion materials permit spatial profile analysis of UV lasers with wavelength in the range of 193nm to 360nm.
- Wavelengths from 190 to 360nm
- Spot sizes from 150μm to 30mm*
- Energy density from 50μJ/cm² to 0.6J/cm²**
* Maximum measurable spot size is 4 times the CCD...
You can now measure high average powers using moderate power sensors, using a new feature in the StarBright meter called “Pulse Power Measurement”. Thermopile sensors are often used to measure single shot pulse energy; the instrument can easily calculate instantaneous pulse power from this if it knows the pulse width (since power = pulse energy / pulse width). With the StarBright set to “Pulse Power” mode (supported from StarBright firmware version 1.30), the user enters the length of the pulse, fires the pulse, and StarBright then displays the instantaneous power...
Logging periods and limitations, both for when logging on-board the meter, and when logging on a PC with StarLab.
- Onboard logging with Nova II, Vega and StarBright meters: The number of measurements that can be stored is firstly limited by the amount of memory available to the meter as detailed in the catalogue table below:
- On the Nova II (and hence its offshoot the Vega) we did set an arbitrary maximum time...
BeamGage is a multiple process application which requires local (not network or internet) port access to communicate. This allows for a great amount of flexibility when using multiple camera or multiple analyzer configurations. By default the port range in use is TCP 10100-11100. This can be reconfigured if these ports are already in use by another program or system.
BeamGage has three process types which will run. Spiricon.ConsoleService.exe is a Windows Service process that launches the connections to cameras. Spiricon....
Wavelength: In physics, the wavelength of a sinusoidal wave is the spatial period of the wave— the distance over which the wave's shape repeats,[1] and the inverse of the spatial frequency. It is usually determined by considering the distance between consecutive corresponding points of the same phase, such as crests, troughs, or zero crossings and is a characteristic of both traveling waves and standing waves, as well as other spatial wave patterns.[2][3] Wavelength is commonly designated by the Greek letter lambda (λ)...
A developer of power-bed additive manufacturing systems needed a beam profiling system that could be used by their field technicians for setup and maintenance of customers’ lasers. The view of the caustic was not as important as the laser measurement results
Commercially available laser beam profiling products are used throughout the world to research, develop, manufacture, and test the quality of lasers and systems that use lasers. These measurement systems are also commonly employed to test and evaluate the spatial intensity distribution of other light sources.
Laser beam profiling products are typically composed of a 2-dimensional sensor array, optical imaging and attenuation optics, and software that displays, analyzes, and records the visual representations of the distribution of light for measurement,...
A quote attributed to Heraclitus, a Greek philosopher, states that change is the only constant in life. Change often comes as a surprise and is seen as a painful part of life; however, that is not always the case. At Ophir-Spiricon we believe that change can be positive. We continuously look for ways that we can improve the customer experience, and often, we succeed.
One of our customers, Inter-Coastal Electronics, recently sent equipment to us for recalibration. Their buyer shared her experience with us and...
Our current recommendation is to use DI water that has been titrated to a neutral pH (using a bit of sodium hydroxide for example – see FAQ at https://www.ophiropt.com/laser--measurement/knowledge-center/faq/7805 The commercial additive Optishield Plus is also recommended for systems such as ours that have copper and aluminum in them. It has the additional benefit of including a biocide to prevent the buildup of bacteria and algae...
The center of the NanoScan can be found by the following steps:
- Connect the NanoScan to the computer and open the software.
- Start recording data
- Go to the Computations tab and select the Rolling mode
- Go to the Profiles tab
- Under the Origin Location section of the Profiles tab
- Click on the Default button
- Click...
Calibration Method and Estimated Accuracy for Ophir High Power Sensors
Ophir models 5000W, 10K-W and Comet 10K are calibrated using relatively low power lasers ~ 150 - 300W. Using such low power lasers to calibrate the instrument vs. the high power at which the sensors are used raises the question of calibration accuracy. The following explanation clearly demonstrates that the 5000W, 10K-W and Comet 10K are indeed accurate to ±5% over their measurement range. The 5000W and 10K-W sensors work on the thermopile principle, where the radial heat flow in the absorber disk causes a temperature difference between the hot and cold junctions of the thermopile which in turn causes a voltage difference across the thermopile. Since the instrument is a thermopile voltage generating device, it must be linear at low values of output. Therefore, if it is shown to be linear at powers which are a significant fraction of the maximum power, it will necessarily be linear at very low powers and if the calibration is correct at low powers, it will remain correct at high powers as well. On the other hand, although the output may be linear at low powers, there may be a zero offset that, due to the relatively low output at low powers, will cause an error in calibration...
Ophir models 5000W, 10K-W and Comet 10K are calibrated using relatively low power lasers ~ 150 - 300W. Using such low power lasers to calibrate the instrument vs. the high power at which the sensors are used raises the question of calibration accuracy. The following explanation clearly demonstrates that the 5000W, 10K-W and Comet 10K are indeed accurate to ±5% over their measurement range. The 5000W and 10K-W sensors work on the thermopile principle, where the radial heat flow in the absorber disk causes a temperature difference between the hot and cold junctions of the thermopile which in turn causes a voltage difference across the thermopile. Since the instrument is a thermopile voltage generating device, it must be linear at low values of output. Therefore, if it is shown to be linear at powers which are a significant fraction of the maximum power, it will necessarily be linear at very low powers and if the calibration is correct at low powers, it will remain correct at high powers as well. On the other hand, although the output may be linear at low powers, there may be a zero offset that, due to the relatively low output at low powers, will cause an error in calibration...
An integral part of the Ophir-Spiricon culture is an engendering of the practice of continuous improvement. We do this with one focus in mind: Customer Satisfaction. The question driving all of these improvements is, “What can we do to provide better service to our customers?” One element of this is captured in the development of a system to recognize the improvements made in the Calibration Department.
These improvements come from every person in the department, and are documented...
At Ophir-Spiricon, we realize that our customers are the lifeblood of our company. Because of this partnership, we are driven to provide quality products and services in the most cost-effective way possible. To help you minimize the costs of maintaining equipment, we have put into place many features of our services to support your goals.