DataRay Blog

M² Measurement

As leaders in the laser beam profiling business, we have worked with M² for decades. In this blog post we discuss M², when to use it, and the way it is measured. M² is a very useful measurement for a certain subset of laser beams—those that are predominately Gaussian—and determines how tightly an actual laser beam can be focused in comparison to a theoretically perfect Gaussian beam. Sometimes, customers wish to use M² as a laser beam metric, even when it isn't the most appropriate metric to use for their application. Even if M² isn't the right diagnostic metric for your beam, we would love to work with you and design a custom metric to assess the quality of your beam.

CMOS vs. CCD Sensors and Overview

CMOS and CCD image sensor technology was developed in the 1960s. Although for the last forty years CCD sensors have dominated the market, improvements in CMOS sensor design have catapulted them to a growing market share and the CMOS seems poised to replace the CCD in many applications. Often times, customers familiar with the past advantages of CCD sensors question the use of CMOS image sensors in laser beam profiling cameras. We seek to provide a short overview of the CMOS sensor’s advantages and the improvements that have enabled it to become a contender in the image sensor market.

Small Beam Width Theoretical and Experimental Error

One of the most important measurements in laser beam profiling is the beam width measurement. A common question we see is “How small of a beam can I measure with this camera?” Generally, we recommend that the user ensures that they cover at least 10 camera pixels along each axis to get a good measurement. The rest of this blog post will examine why we provide this guideline, discuss the theory behind it, and use some measured data gathered from several DataRay cameras to validate the theory. We will also provide what approximate error values to expect when covering small numbers of pixels.

Flat-Top Beams and Plateau Uniformity Calculations

A flat-top beam (otherwise known as a top-hat) is used in various applications where a controlled profile is desired (i.e. a uniform density across the irradiated surface). Passing a Gaussian beam through special optics will create the flat-top beam and is the most common way of generating a flat-top beam. Uniform excimer beams are used in many material processing applications (e.g. creating integrated circuits). Industries such as welding, drilling, and medicine also make extensive use of flat-top beams.