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Dr. Ephraim Greenfield

Background

Intense Pulsed Light sources are widely used in skin treatment. These pulsed sources are used either coupled through the air to the skin or coupled directly to the skin with gel between the source and the skin to eliminate reflections of light.

How does one measure the output of such a source when gel coupled to the skin of the patient?
Ophir has defined the output of such a device as follows: the output will be defined as...
Julian Marsden

Abstract
This document describes the inherent problems involved with measuring average power for low frequency pulsed laser sources, and describes the new “Low Freq. Power Mode” being offered on many Ophir devices and meters to solve these problems. It describes how to use the new mode and mentions some tips for obtaining best results.

Introduction:
VCSEL sources have become very popular in the last few years and are being used for many applications in...

By 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 reconstruction can be more easily accomplished using these devices as accurate measuring tapes...

“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...

We recently came across an interesting customer problem, in which every time he disconnected the Fiber Optics 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...

Via StarLab it’s easy.

Via RS232: We do not provide RS232 commands for starting the logging on the meter, so this is not directly possible.

However, the customer can use the Simulate Key-press command to provide a virtual keypad control in order to set up and start the logging on the meter. Extracted from our “Remote Control” documentation:
 

By Dick Rieley, Field Sales Engineer III, Mid-Atlantic Region, Ophir-Spiricon

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...

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 and...

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...

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...

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.

  1. 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...
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...
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...

By Kristen Winterton, Calibration Technician

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...

By Kristen Winterton, Calibration Technician

Watch the Fastest Calibration in the Industry

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...

By Kristen Winterton, Calibration Technician

At Ophir-Spiricon we pride ourselves on providing quality in every step of our service to you. To validate and measure our commitment to quality, Ophir-Spiricon has recently renewed our ISO/IEC 17025:2005 accreditation by ACLASS. We validated that we are still in compliance for our calibration systems. ISO/IEC 17025:2005 is an accreditation that provides the general standards for testing and calibration labs worldwide. It helps us strive to complete...

By Kristen Winterton, Calibration Technician

The calibration laboratory at Ophir-Spiricon recently expanded the Scope of Accreditation of our ISO/IEC 17025:2005 Accreditation by ACLASS to include Beam Profiling equipment. This addition to our Scope of Accreditation expanded our current portfolio of offerings to include all product lines calibrated in the calibration lab at Ophir-Spiricon.
 ...

By Kristen Winterton, Calibration Technician

Spiricon has worked tirelessly over the course of the last several years to enhance the customer service experience and to continue to provide a quality service to our customers. With customer satisfaction one of our main objectives, we have developed processes at all levels that help us reach this goal. Our highly skilled technicians have been rigorously trained to ensure that each piece of equipment that is calibrated and repaired is done so with accuracy...

By Kristen Winterton, Calibration Technician

At Ophir-Spiricon we have raised the standard of service. One of the pillars of our business model is customer satisfaction, and we firmly believe that the level of customer focus we provide makes us stand out in our industry.
 
The services provided by our Recalibration and Repair department have continually evolved to become what they are today. For your convenience, we have developed many “extras” and integrated them into a...

At very low powers the zero offset becomes important. This means that the sensor reads some value even if there is no input into it. This can be because of external heat sources or the fact that the meter is not zeroed properly. Now say that there is a zero offset of 10mW = 0.01W. If we are reading a laser of 10W, then the meter will read 10.01W, an additional error of 0.1%, very small. But if we are trying to measure 0.1W, then the reading will be 0.11W, an error of 10%! This is illustrated in the diagram below...

By Kristen Winterton, Calibration Technician, Ophir-Spiricon LLC

A common concern that I have heard throughout my years with Ophir-Spiricon is that many people do not understand the necessity of calibration. They do not understand what the calibration process entails, and how it can save them money, time, and frustration.

Our products are used throughout the world in many different areas, from medical and scientific processes to defense and...

Absorptive glass filters have varying degrees of non-trivial fluorescence, which can be problematic in some applications. Here’s a fairly simple way to check if a filter is fluorescing:
  • Place the filter in a collimated beam with a power meter behind it, located very close to the filter and measure the signal.
  • Increase the distance (>> 10x the beam diameter) from the filter to the power meter and measure again the signal..

Abstract
The discovery of Rayleigh Scattering by 3rd Baron Rayleigh, John William Strutt, served an explanation of why the sky is blue during the daytime and different hues of orange, pink, and purple in the early morning hours and at dusk. But it was only recently that this phenomenon has been applied to the measurement of high-powered lasers. Only through the measurement of the laser source and laser system can the user of the laser fully understand its performance and then start to control the processes in which they...

To handle a beam who’s power is unstable, you’ll first need to observe the behavior of the readings. Unstable power can take two forms:

1. Fluctuations , where the time constant is short,

Fluctuations , where the time constant is short,

2.Drift, where the time constant is longer

...

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