• The application does not require “state-of-the-art” phones. It works perfectly OK with 3 year-old HTC Legend (that was not top of the line phone even when it was first announced) and it works well with our test phone which is defined mid-to-low range in today’s phone standards.
• The software does require android version of 2.3.3 and above. According to latest analysis they account for 65% of current phones (this information comes from google analysis of active phones). Since version 2.3.3 is over 2.5 years old, almost no new phones are sold with older versions . The contract commitment in the US is usually two years, so most 2.2 and 2.1 phone owners there will probably upgrade to newer phone in the coming months.

To download the Quasar Reader App

An explanation of how we do this is provided below (A). In addition, a recent check of Ophir’s 5000W head by PTB in Germany shows excellent agreement between our calibration and their standards. The details of the correspondence between our sensor and their standard at powers up to 1400W is included here (B).

A. High Power Measurement Calibration Method and Estimated Accuracy of Models 5000W and 10K-W

Range Selection
Use the lowest range that is larger than the pulse energy to be measured. For example, if you want to measure a 2.7 Joule pulse, use the 3 J range instead of the 30 J range. This will allow for maximum resolution (a 2.700 J reading versus a 2.70 J reading).

Threshold Selection
For most energy measurements, the default MEDIUM setting is appropriate. If taking measurements in a noisy environment or where there is a high level of background thermal radiation, the instrument may trigger spuriously on the noise or the background radiation. In this case, the user may select the HIGH threshold setting. This will prevent false triggering and ensure the sensor is measuring the intended pulse. If you are measuring small energies and the unit does not trigger, set the threshold for LOW. LOW threshold may also be used for the best accuracy if the energy measured is less than 10% of the range. For example if measuring less than .3 J in the 3 J range, LOW threshold is often more accurate, and will be more repeatable.

The global medical industry incorporates thousands of lasers into its arsenal of treatment tools. Wavelengths from UV to Far-infrared are used for everything from Lasik eye surgery to cosmetic skin resurfacing. Visible wavelengths are used in dermatology and ophthalmology to target selective complementary color chromophores. Laser powers and energies are delivered through a wide range of fiber diameters, articulated arms, focusing handpieces, scanners, micromanipulators and more. With all these variables, medical laser service personnel are faced with multiple measurement obstacles. At the Laser Training Institute (lasertraining.org), with headquarters in Columbus Ohio, we offer a week-long laser service school to medical service personnel. Four times a year, a new class will learn the fundamental concepts of power and energy densities, absorption, optics and most of all how lasers work. With a nice sampling of all the major types of medical lasers, the students learn hands-on calibration, alignment and multiple service skills.

Ophir pyroelectric sensors can measure energy at very low repetition rates, what is called “single shot” energy as well as at various repetition rates all the way up to the maximum in the specification for such sensors. There seems to be a misunderstanding among users that pyroelectric sensors cannot measure single shot energy. This probably comes about since thermal sensors can only measure at very low repetition rates (~0.2Hz), then it is assumed that the converse applies to pyroelectric sensors, i.e. that they only can only measure at faster repetition rates, but this is not true.

What is the best way to measure the power of a laser that is, unfortunately, not stable, where the power is drifting upwards or downwards. I am making a measurement taking readings by hand and logging to computer?

The best way to measure in such a condition is to take statistics of a number of readings. In order for the sample to be truly random, you should a given intervals look at the reading and take it down as seen with no attempt to wait for it to stabilize or reach a "better" value.

If, for example, you need to measure energy at various points along an optical setup in order to characterize each stage of your system, you can place a sensor at each location along the way and connect the sensors in parallel to, say, a multi-channel Pulsar, and log the data using the StarLab application. So long as you open all channels in a single window and log from that window, all the channels will be synchronized with the same zero point. Knowing that, you can rely on the time stamps to tell you which pulse in each channel corresponds to which pulse in the other channels.

When using a Fiber Adapter accessory together with one of Ophir's sensors, it is important to be aware of the power/energy density that is going to reach the sensor's surface.In most cases, the fiber adapter locates the fiber tip far enough away from the absorber surface that the spot diameter on the surface will be large, and problems of damage avoided. However, that is not always a certainty! For example, when using a sensor from the PD300 series, especially with filter IN, this distance could be quite small. A power level that is within spec limits could still result in a power density on the filter that is too high, and the result could be damage to the filter. In most cases, as noted, this is not a concern, but in cases where any one parameter seems like it is going to be near a limit, a quick sanity check is a good idea.

See http://www.ophiropt.com/laser-measurement-instruments/laser-power-energy-meters/knowledge-center/tech-tips/fiber-adapter-accessory-