Tutorial: Can a Speeding Driver Avoid Paying a Fine by Claiming the Police LIDAR Meter was Incorrect?
Most drivers get caught speeding at some time during their driving experience. A common scenario occurs when a policeman uses a LIDAR speed meter to indicate that a car is over the speed limit. When the car is caught and pulled over, the driver shows a surprised, innocent face, attempting to get out of a fine. But when the policeman shows the driver the reading on his LIDAR speed meter he knows he’s going to have to pay. Can the driver claim that he was within the speed limit, claiming that the LIDAR instrument is not calibrated recently?
Various LIDAR instruments may be used to measure speed, direction of motion of a motor vehicle, and the distance to another moving vehicle. LIDAR instruments are used by the police to enforce speed limits and to analyze car crashes or crime scenes in order to reconstruct the scenes.
Tutorial – Caution: Lasers Can Seriously Damage Instruments
A common thread running through many Frequently Asked Questions relates to damage of measuring sensors.
Many applications involve considerable powers and/or energies; since laser measurement has us deliberately putting a measuring instrument in harm's way, let's have a look at the various effects a laser beam can have on an instrument in its path.
Ophir Power/Energy Meter Calibration Procedure and Traceability/Error Analysis
By Dr. Ephraim Greenfield, CTO, Ophir Optronics
This document discusses the interpretation and basis for stated measurement accuracy of Ophir Laser Power/Energy meters.
1. General Discussion
2. Combination of Errors and Total Error
3. Analysis of Power and Energy Calibration Errors
4. Detailed Analysis of Power and Energy Calibration Errors
How to Properly Select a Laser Power or Energy Sensor
By Dick Rieley, Sales Manager, Mid Altantic and Southeast Regions, Ophir-Spiricon LLC
The selection of a sensor to accurately measure the power of a laser or energy of a pulsed laser can seem like a simple and easy procedure. However, many times the selection process is limited to choosing a sensor that only meets the range of power or energy to be measured, leaving out several other essential criteria of the laser specifications; that without their consideration, can allow the wrong sensor to be selected, the laser to be measured inaccurately and likely to cause the sensor to fail prematurely.
Watch Our Laser Measurement Video
Common Reasons for Photodiode Sensor Damage or Out of Tolerance Conditions
We have included this document with your recent calibration order because we have noticed an out of tolerance condition obtained from your equipment when returned for calibration. This document was created to assist our valued customers in the proper care and maintenance of Ophir photodiode sensors. The following information is for reference only. If you have any reason to believe that the sensor is no longer performing within the original specifications, we always recommend that you send it in for repair and/or recalibration by our trained technicians to bring the unit back to the proper NIST traceable standards.
Ophir photodiode sensors can be used for many years without any repairs when used with the proper laser optical setup. Many of our customers have sensors that are using their original absorber that are over ten years of age. We hope that this document will enable you to also enjoy the long life and reliable results that Ophir- Spiricon is known for.
Read More»Common Reasons for Pyroelectric Sensor Damage or Out of Tolerance Conditions
This document was created to assist our valued customers in the proper care and maintenance of Ophir-Spiricon pyroelectric laser power sensors. The following information is for reference only. If you have any reason to believe that the sensor is no longer performing within the original specifications, we always recommend that you send it in for repair and/or recalibration by our trained technicians to bring the unit back to the proper NIST traceable standards.
We believe that Ophir pyroelectric sensors can be used for many years without repair when used with the proper laser optical setup. We hope that this document will enable you to also enjoy the long life and reliable results that Ophir-Spiricon is known for.
Read More»Accurately Characterizing High Power Laser Diodes
By Mike Martino BlackBox Technologies June 2010
Careful measurements are considered when testing the optical power, current, voltage, wavelength, and temperature of high output laser diodes. The test system energizes and measures the laser parameters as it will be used in the application. In some critical constant wave (CW) applications, the required output power from the laser is pushing the laser’s maximum specifications. Therefore, an accurate, stable, low drift laser power meter is required.
Laser Power / Energy MeasurementStriving for ever increasing accuracy
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)
Common Reasons for Thermal Sensor Damage or Out of Tolerance Conditions
This document was created to assist our valued customers in the proper care and maintenance of Ophir thermal laser power sensors. The following information is for reference only. If you have any reason to believe that the sensor is no longer performing within the original specifications,we always recommend that you send it in for repair and/or recalibration by our trained technicians to bring the unit back to the proper NIST traceable standards. We believe that Ophir thermal sensors can be used for many years without any repairs when used with the proper laser optical setup. We hope that this document will enable you to also enjoy the long life and reliable results for which Ophir-Spiricon is known.
Read More»Yield Improvement by Online Measurement and Analysis of Laser Energy Using Ophir’s Quasar
by Yoram Shalev, Sales & Marketing Director, Ophir Optronics, LLC
The Quasar wireless Bluetooth laser power and energy measurement interface allows quick and trouble free installation of complex measurement systems in an existing manufacturing environment, with a minimum of cable laying and disturbance to the facility’s operations.
This was demonstrated in a project undertaken recently, and is a typical example of what of multi-user systems see in the field.
Read More»QUASAR Laser power measurement through the air
One of the inconveniences in the measurement of laser power and energy is what to do with the cables connecting the display to the sensor. These cables are of a limited flexibility and they clutter the workspace where the measurement is to be done. Sometimes, due to their stiffness, a motion of the cable moves the sensors and misaligns the set up.
Read More»Ophir PD300 Photodiode Sensor Spectral Response
By Dr. Ephraim Greenfield, CTO, Ophir Optronics
Ophir Photodiode sensors use silicon, germanium and InGaAs sensors together with built in and removable filters. The spectral response of these type of sensors vary widely with wavelength. When used with our smart displays or PC interfaces, the sensitivity factor for the relevant wavelength is automatically set when the user inputs the laser wavelength.
Read More»How to Select Power/Energy Sensors
By Yoram Shalev, Sales & Marketing Director, Ophir Optronics, LLC
The need to accurately measure laser power and energy has increased as more of these systems are used in medical procedures and industrial processes. Although a fairly simple process, this measurement is not as straightforward as an electric power measurement. With lasers, more attention must be paid to the selection of the right sensor as since different sensors perform different measurements. Selecting the wrong sensor can destroy the laser.
Read More»RP Sensors – when should they be used?
By Dr. Ephraim Greenfield, CTO, Ophir Optronics
The RP sensors (RP for Rapid Pulse) are a specialty but unique type of energy sensor that can fill an important niche in laser power/energy measurement. RP sensors are rather expensive and bulky and have other limitations and therefore are not the preferred solution when a pyroelectric sensor will do. However, there are situations where it is the only energy sensor that can be used.
The main situations in which RP sensors are useful are
- For very long pulses >10ms and very large duty cycles such as are typical in many pulsed diode laser applications.
- For very high average powers greater than 50W with repetitive lasers.
- When you want to measure the temporal pulse shape as well as the power and energy.
- When you want to monitor for missing pulses
Power and Energy Meters: From Sensors to PC
By Ilan Haber, Ophir Optronics Ltd
From the time of its invention, more than 30 years ago, the laser power meter was generally
comprised of two parts: a measurement head and a display box. It was always considered
better to have such an arrangement with a cable connecting the two because of the hazardous
nature of the laser beam. As the display of the results is separated from the measurement
head, so are the eyes of the operator separated from the laser beam.
Now that the PC is an indispensable part of the office and the laboratory, it is important to be
able to integrate measurement instruments to the PC, particularly instruments that can gather
large volumes of data. There is a need for a unified connectivity architecture wherein all
measurement heads are compatible with all display boxes and are then easily connected to the
PC.
Power and Energy Meters: From Sensors to Displays
From the time the first laser was built, physicists probably thought, “That’s great! Now how do we measure it?” Thus laser power and energy meters were born.
Since lasers are good sources of concentrated heat, it was probably assumed that heat sensing methods would best be employed for measurement. The simplest device to measure heat is a thermocouple. A simple device to measure light is a photodiode. So, some enterprising engineer designed and built such a device. Then they needed an instrument to display the results and give rapid feedback in order to tweak, align, or adjust the laser for maximum output. Early displays were basically analog meters that had a needle on a dial that went from left to right as the laser power went up.
Laser Power and Energy Measurement
Ophir standard power and energy measuring heads and displays all use smart head technology. This means that all the configuration and calibration information is stored in a small memory chip inside the smart head plug, so that when the head is plugged into the display the correct power and energy are read. Except for some OEM heads, this technology is used in all Ophir heads: pyroelectric, photodiode, scanned beams, medical heads, etc.
Read More»Calibration Capability at Ophir
Calibration is perhaps the most important of our products. We have a complete line of calibration lasers so that we can always calibrate at or near the customer’s wavelength. These lasers include powers up to 400W and both CW and pulsed lasers. In addition, we have a number of heads calibrated at NIST used as calibration standards. Below is a list of the calibration wavelengths used at Ophir in calibrating our standard catalog heads. Usually the calibration is done at representative wavelengths within a band of wavelengths where the head is spectrally flat. The calibration then applies to any wavelength in this band. The specifications note the maximum additional error in each wavelength band due to variations incalibration between the wavelength of calibration and the wavelength of measurement.
Read More»
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