The DPSS Primer...(and how lasers work)

MrB said:

Hi Andrew,
Is it possible to do this without the Q-Switch for CW operation?
If so, what sort of efficiency could one expect?
Say you use 3x 20W side pump diodes, would it be reasonable to expect say 15W CW @ 1064nm (using a 25% efficiency guesstimate)
I would like to do something like this for a CNC engraver/router, but starting to think a cheap chinese CO2 tube, even with it's lifetime issues.. may be easier.

Edit: Oh and what is going on in your avatar? Too small to see...

Click to expand...

Some diode-pumped Q-switched lasers can run CW without modification, however, most can't.

Q-switched lasers often have different optics (i.e. reflectivity of the OC will differ, as well as cavity layout) to lasers designed from the ground-up to run in CW. As well as that, 'hybrid-mode' lasers are often very fickle to run and maintain, and even minor operator error can lead to destruction of cavity optics (Laserscope owners will know this well).

If you want to CNC, the CO2 laser would be a better choice. It would be more stable, it would be cheaper, and it would also be easier to implement (instead of a complex CW DPSS system).

CO2 also has another advantage- the wavelength of 10600nm means it is absorbed by normally reflective or transparent substances, allowing it to cut perspex as well as some metals, for example.

As for my DP, it's of the TehknoScan DYE-SF-777 ring dye laser.

Here's the full picture:

Tekhnoscan Company. CW single-frequency ring lasers.

Thanks for the reply Andrew.
I wasn't thinking of modifying a Q-switched, but starting from scratch.
Basicaly, I was looking at using a few of the 20, 40 or 60 watt Coherent diodes for CNC, but due to their crappy beams I thought about using one of the 4 or 5mm Nd:YAG rods that crop up on ebay from time to time. Using correct HR and OC ofcourse.

As you say, CO2 makes sense. I had pretty much come to that conclusion myself.
The chinese 40W tubes are very cheap... tho for the work I'd like to do the 80 and 100W tubes are more realistic but ofcourse the prices jack up to where the Coherent diodes are more appealing again.

Thanks again for replying.