Pump spot optimization....

[MechEng3]

Anyone measured the spot size on a CNI 1 watt 532nm? I have a spot of 635 microns....roughly .025". I get lasing results but not optimal. Just wondered if anyone else has taken notes on this aspect of these lasers.

[mixedgas]

How are you measuring that ???

Steve

[MechEng3]

The way I have to perform it here is for the pump spot to be photographed with thermal image camera. The spot is on a piece of steel that has been blued or blackened with acids. The image then can be optimised as to the heat pattern of the image and a grid in place for a very close measurement in the PC. The image capture must take place quickly as the heat spreads rapidly...hence a quick pulse on the mod input of less than 2 seconds. It is crude, but seems to be within 10% of findings and previous testing of known sizes for comparison. It is not in color...shows brightness contrast. It is an old Bullard brand fireman's type unit...still pretty effective....though it's borrowed. I may purchase one...I like it a lot.

[mixedgas]

I love thermal imagers, in at fact my former employer I insisted on having a Raytheon around. Nice, can see a mouse at hundreds of yards.

However we need to get you a better technique.

will start working on it, I usually use a pinhole and a slide, or a CCd.

Steve

[Junktronix]

I don't have an answer for you, but I am curious what the insides of a 1W chineeze laser looks like. Is it just a horribly overdriven single emitter diode end pumping a sliver of vanadate or do they actually use anamorphics to get a circular pump profile? How much pump power do the use anyway?

[Laser Ben]

The CNI units are pretty well made, some of the other ones can range from high quality to really shoddy "how does that manage to work!?" quality.

[MechEng3]

Here is a pic of a 473 CNI.....the components are very similar...some only larger. The green's are very simple on first impression....tip...look closely at the stripe width of the diodes and the placement of optics. Some prefabbed/aligned before install into the laser head. Nothing to compare with a Coherent,JDS,or a Euro made unit. This one went through a diode replacement and general temp/tune/clean. I have found sizable chunks in these....solder...misc. bits of debris
The laser dies are very long and narrow say 150um X 4.8mm. The optimum current is near 6 to 8 amps..[ 1 watter]..depending on how old and the diode itself. Most are FAC lensed with only one or 2 correction lenses beyond that.