Sigma LBA-714PC, LBA-710, LBA-300, LBA-712, LBA-708, LBA-500PC, LBA-700, LBA-400 manual Histogram

3.2.6.8.2Far-Field Divergence Measurements

The Far-Fieldmethod requires you to measure the beam widths of your laser at two known locations in the beams far-field. The change in size is used to compute the rate of beam divergence in mili-radians.

First collect a pair of Reference beam widths. The Reference data should be acquired at the smaller beam width location. Click Stop!, and note the location of your camera in the beam path.

Open the Options…Computations dialog box. Check the Divergence box and select Far Field in the drop down edit control. Click the Set button to transfer the current Reference beam widths into the provided edit control boxes.

Note: You can manually enter these values from a previous measurement if you know what they are. The Set button is provided to facilitate making this entry.

Figure 27

Move your camera to the larger beam width sample location, noting the distance traveled by the camera. The distance traveled is the separation distance between the two sample locations. Enter this Separation distance in meters. Click OK and then Start! The divergence results will be computed for both the X and Y axes based upon how the current beam size has increased from that of the Reference sample.

Notice: It is not recommended that Elliptical be enabled when making this measurement, rather you should rotate your laser/camera to be X and Y axis aligned. Under certain conditions the rate of divergence could cause the major and minor axes to swap in the far field region, yielding false results.

3.2.6.9Histogram

Check this box if you want to view a Histogram of your laser beam’s energy distribution. The Histogram graphic and numerical results will appear in its own window of the LBA’s main display. The size of each bucket in the histogram is user programmable. Bucket size is based upon the integer values produced by the A to D converter. If required, the bucket size will be converted to floating point values to reflect the processing effects of an energy calibration. The buckets are sized up (plus) and down (minus) from zero.

Operator’s Manual	73	LBA-PC
Doc. No. 10654-001, Rev 4.10