I found a big laser at the scrap yard - Page 1
Forum section: electronics / projects

author: jujun
author_rank: Regular Contributor
timestamp: November 07, 2023, 01:59:19 pm
content: Hello,I have found a big laser at the scrap yard. It seems to be an industrial engraving laser. (Rofin powerline E30 IC)It looks like a Q-switched pumped laser with two 50W fiber-lasers (Rofin Laser Diodemodule 780-1080 nm 50W).There is a security that keep the laser power supply in short circuit when not in use, I guess for ESD and security.The Q-switch (Rofin HG-24 Q-Switch) seems to be an acoustic one, using a RF signal to drive it.I have not found any exact datasheet about the Q-switch driver, but it seems that the pinout are almost the same. Power and analog signal for frequency offset.My understanding of the Q-switch is : opticaly closed when the RF is applied.I guess there is also some kind of mechanical obturator to avoid any CW laser going out of the Q-switch.Is it right?RF driver => Q-switch => unknow enclosure => 1mW red laser pointer added to optical path => outI managed to get the small red laser working. (at least this is safe)The unknown enclosure includes an optical power meter (water cooled) (connector X29), and something else unknown with a connector (X25). I don't want to open the enclosure yet. Any idea about it?When I will try to make it work I will borrow proper safety glass from a laser lab. (for the right wavelength)And will take a lot of care about security.I have not found yet the exact datasheet of the two lasers. On similar ones, I have found 2.9V max, and min 10A.Do you think it's possible? So I only need a current power supply right? Why the wavelength is not fixed?Any info are welcome!

author: jujun
author_rank: Regular Contributor
timestamp: November 07, 2023, 01:59:52 pm
content: here is one pict from the other side

author: CatalinaWOW
author_rank: Super Contributor
timestamp: November 07, 2023, 04:14:01 pm
content: I can offer no specific information, but have a couple of comments.At the cost of these units it is far more likely that the unit was scrapped because it didn't work. But you might have gotten lucky.The wavelengths are the diode pump modules and are potentially quite different from the laser wavelength. Be sure to find the actual laser wavelength when selecting protective gear. Also recognize that at these power levels solid non flammable absorbing materials should be your first line of defense.The Q switch changes the gain in the laser optical path. A laser is an optical resonator and the avalanche of power (stimulated emission) comes as light reflects back and forth between mirrors at the end of the path. Usually that means the Q switch is changing either from reflective to transparent. The timing of this change relative to the pump cycle can be important.The pump diodes are usually worked pretty hard. Duty cycle can be important.

author: KE5FX
author_rank: Super Contributor
timestamp: November 07, 2023, 04:27:15 pm
content: interesting piece of hardware. I don't think he's on here, but you might send a note to Les ofLes's Laband see if he's familiar with it.I almost always learn something interesting about lasers whenever I come across his channel. Can't recommend it enough.

author: coromonadalix
author_rank: Super Contributor
timestamp: November 07, 2023, 06:21:22 pm
content: Rofin HG-24 HG24 Switch DC13V/40.68 MHz ??ROFIN HILBERLING HG-24 SWITCH HF-OUT 5.....20WEDIT sorry

author: jujun
author_rank: Regular Contributor
timestamp: November 07, 2023, 07:10:59 pm
content: Quote from: coromonadalix on November 07, 2023, 06:21:22 pmThis is the driver of the Q-switch.

author: jujun
author_rank: Regular Contributor
timestamp: November 09, 2023, 01:48:48 pm
content: I found that the X25 connector drive a solenoid removing the power meter from the optical path.

author: ajb
author_rank: Super Contributor
timestamp: November 09, 2023, 07:08:41 pm
content: Quote from: CatalinaWOW on November 07, 2023, 04:14:01 pmMoreover, this is a pulsed laser, so the peak power will be VASTLY higher than the average power, which makes it significantly more hazardous than the power rating would suggest. DO NOT rely on safety glasses alone for this.It looks like the same unit is sold under Coherent's PowerLine E Series brand (PDF datasheet), which claims a pulse energy of 360nJ and pulse width of 40ns for the E30. That puts the average pulse power at 9kW -- the peak of the pulse will be even higher depending on the pulse shape. Those high peak powers are what allow lasers like this to directly ablate metal, they will do much worse to skin and eyes if you are not careful.The pump diodes are probably 808nm, which is typical for pumping Nd:YAG and Nd:YVO lasers, which lase at 1064nm. Some of the 808nm pump light may make it through to the output, which is why the compliance label says "780-1080nm". Technically the label should include the 638nm from the alignment laser, but that's only 1mW so not a huge safety concern. The YVO crystal will be in the big block marked "A6". Even if the pump lasers are functional, there may be problems with the secondary cavity rendering it non-functional. Repairing anything in the cavity of a laser is not trivial, and will be even harder here since you won't be able to directly see what's going on with the 808nm or 1064nm beams.

author: jujun
author_rank: Regular Contributor
timestamp: November 10, 2023, 01:36:37 pm
content: I managed to get the Q-switch driver working. Next step is how to trigger a "fire" from the driver. I guess I have found how, I just need to test. (Of course without powering the lasers pumping)

author: jujun
author_rank: Regular Contributor
timestamp: November 10, 2023, 01:53:48 pm
content: In the big block marked "A6", the Q-switch itself, there only two electricals connexions, one coaxe from the RF generator and two other wires. Any ideas about the use of these two wires? (with SMC connector, but not a coax cable) ?Maybe there is a kind of mechanical obturator to avoid any CW laser going outside?Or a sensor?There is an optical power measurements a little later in the beam path, so I don't think it's something like this.And it looks like I should not open the big block ...