We suspected the PMT for a long time. We even got some of the R&D engineers here from Japan to look at our application and the problem we're having. They did have a few suggestions, but in the end what we kept coming back to is that the problem stays the same when we change PMT's, but it will...
Sounds good. I appreciate your help. I've been told to put this on hold for a little while and handle some other projects for the next few weeks. Enjoy your holidays.
First, to give things their proper name: lasers have transverse (sometimes called spatial) modes as well as longitudinal ones. Single mode applied to a laser diode commonly refers to transverse modes; there may still be multiple longitudinal modes. When I said single mode I meant (longitudinal)...
One of the issues we have is that there is no room for anything. The diode is mounted such that there's really no room for anything else near it. There's the diode mounted inside a collimating lens housing, which is mounted in a centering disk which holds the laser centered in a small tube...
No insult taken, I understand.
The LD does have three pins. According to the schematics, pin 1 - Anode, pin 2 - NC, pin 3 - The cathode of the diode is connected to the package which is connected to pin 3. I'm working on a reply to a previous comment that will have pics and descriptions of...
The data sheet for the diode says:
"a high-power, high-efficient AlGaInP semiconductor laser which provides a stable, single transverse mode oscillation"
attached is an image stolen from Wikipedia which is what I saw after passing the beam through a 150um orifice. I'm guessing this is the...
Thank you for your reply and I will certainly re-submit the question in the EE section.
One thing I have tried is to add some of the thermal compound (similar to what is used to couple heat-sinks to computer processors) to the collars and housing that contains the diode. This does not seem to...
I am using a laser diode to count aerosol particles flowing through a gas stream. The refracted light is being funneled to a photo-multiplier via fiber optics. When there is no gas flowing (and therefore no particles) we are seeing some strange results from the output signal of the...