Today’s various laser applications, from delicate medical operations to heavy material processing, demand high quality laser beams which perform precisely and consistently. In order to ensure a laser is performing properly and efficiently it is necessary to monitor the laser performance using laser measurement devices. Although in some cases it is sufficient to use a laser power meter including a sensor to monitor laser power output, for many cases a beam profiler is necessary to measure as well the beam’s spatial characteristics such as: beam size, shape, intensity, and divergence. Knowing all of the characteristics of a beam could save a user a lot of time and money. In this article we demonstrate with several real examples how Ophir Spiricon and Photon beam profilers and software are used for different applications.
Photodiodes are usually used to measure the power and energy of low power laser beams. Can photodiodes be used to measure low power broadband light sources?
Laser measurement of high-power broadband light sources can easily be measured using standard thermal or pyroelectric sensors. Pyroelectric and thermal sensors generate an electrical current proportional to absorbed heat whether the light creating the heat is broadband or of a single wavelength. Low power sources are usually measured with photodiode sensors. These sensors have a wide variation in sensitivity as a function of wavelength and are usually calibrated to measure a particular wavelength.
When working with pulsed laser sources, laser developers and scientists are often interested in knowing the peak power, the highest power output from the laser. However, most pulsed laser power meters display the total energy of a pulse or alternatively the average power, not the peak power. How can a user measure the peak power of a pulsed laser beam using Ophir laser measurement equipment?
Ophir offers a nanosecond response time photodetector which is designed to measure the temporal behavior of pulsed lasers, the FPS-1 photodetector. The FPS-1 is easily connected to an oscilloscope which displays a temporal trace of the power output during the pulse. Since the oscilloscope does not display a trace of absolute power output over time, but rather the relative pulse behavior and shape, it cannot be used directly to find the peak power. However, with a simple calculation the trace may be used to derive the peak power of a pulse.