Any way to detect 3390nm? (HeNe) - Camera won't work.

[agravlin]

Infrared is expressed as heat, so just stick your hand in front of it!

Just got laid off today, so be happy I even have THAT much of a sense of humor.

 

[aryntha]

At 2mW, I'd be there a LONG time. But - what Heruur is saying is essentially that; basically that's what the TEC would be doing. A LPM too I suppose, I just gotta either get it down to Boulder or finally do the Kenometer thing.

Sorry to hear about the job situation -- that seems to be rather common lately :\

 

[LSRFAQ]

1.15 I'd use the stock cu doped ZnS phosphor link I sent you. Cu is the dopant that enables glowing, its about 6 parts per million fused into the ZnS when its fired in a oven, then ground. So you just buy from the link. I know the Post Apple stuff works.

For 3.39 I do have some spare sensor modules, you need +/- 9 to 15 volts (ie 2 9 volt batteries) and a small metal disk with a chopper wheel on it. You'll also need something to power the TE that cools the sensor. It will run without the TE powered up, but the detection is then weak. The sensor only responds to pulsed IR light, so you need to make the laser "blink". I've gotten away with breaking beams with my spread fingers and watching a scope, but if you want to read it with just a voltmeter, you need a spinning disk with holes in front of it or some sort of spining plastic blade.. Don't care about the speed of the disk etc, as long as something chops the beam, ie fan from a PC, toy something etc.

Deal of the century, one module, one time only, with processing board, working, tested: 35$ and shipping. Thats what I paid for them. They cover 2 to 5 microns. One glitch, cannot be exported out of the states. 3.39 is so damn hard to detect, and high end thermal imagers (military uses 3.5 as well as 8 microns) dont grow on trees, so this is probably the only way you'll ever see it, unless you get lucky with a detector card of the type that is UV pumped. Once you find you have a beam, call Sam Goldwasser and sell him that thing... The module is easy to test, it'll "see" the flame from a propane torch or match. It ignores visible light.

I just looked at a chart, you may still see the 3.39 with the ZnS:cu phosphor, but barely.

PM me if you want one, I'll actually bother to check my PMs for the next few days.

Steve

 

[HIMNL9]

Uhm, maybe an old PIR sensor can work ?

Still have some doubt, cause the heat generated from human bodies is usually in the 9-to-10 microns (9000 to 10000 nm) ..... need to find some datasheets for see what is the "cutoff" wavelenght of the PIR windows .....

 

[aryntha]

For 3.39 I do have some spare sensor modules, you need +/- 9 to 15 volts (ie 2 9 volt batteries) and a small metal disk with a chopper wheel on it.

I just looked at a chart, you may still see the 3.39 with the ZnS:cu phosphor, but barely.

PM me if you want one, I'll actually bother to check my PMs for the next few days.

Steve

Steve, I do want one so I will PM you shortly. No worries on export, no plans to do so. I also ordered some of the phosphor. Thanks for the info and will PM you shortly.

 

[LSRFAQ]

Uhm, maybe an old PIR sensor can work ?

Still have some doubt, cause the heat generated from human bodies is usually in the 9-to-10 microns (9000 to 10000 nm) ..... need to find some datasheets for see what is the "cutoff" wavelenght of the PIR windows .....

You can order piezo IR sensors that will work at 3.5 uM, however the ones for sensing body heat are windowed with a filter for, you guessed it, 8-9 microns or so. This is done to reduce false alarms,

If you can de-can/de-window the sensor, you could try a motion sensor part at 3.5 u.

Steve

 

[aryntha]

Hey Steve - Just a quick bump in re: the PM I sent you in regards to buying that IR sensor.

Still waiting for my ZnSe to arrive, maybe just maybe that'll do the trick, but would like to get something more definite.

 

[HIMNL9]

You can order piezo IR sensors that will work at 3.5 uM, however the ones for sensing body heat are windowed with a filter for, you guessed it, 8-9 microns or so. This is done to reduce false alarms,

If you can de-can/de-window the sensor, you could try a motion sensor part at 3.5 u.

Steve

Uh, i considered the thing ..... i have some unused old PIR sensors, and no problems in decanning or taking away the original window, but then i don't know exactly what to use for substitute it .....

Mean, thinking to replace it with something different, for avoid dust / mist contamination of the sensor surface ..... but i'm not used to work with these wavelenghts, and don't know what materials can be transparent from, say, 1 to 10 microns, and relatively opaque to visible light ..... and i guess standard glass is not the better choice .....

ZnSe glass ? ..... i used ZnSe lenses for CO2, but CO2 is 10500 ..... and they cost a lot, also in surplus market ..... also have an ER:YAG cavity, somewhere, but is practically new, and i don't want to dismantle it just for an experiment (and, anyway, as far as i remember, the inside optics are matched for 2,94 microns) ..... and others are so difficult to find, that is a nightmare ..... maybe ZnSe is still the better choice, if can be found a thin piece ..... or some of the new "exotic" plastics .....


Edit: i just found that "diamond" can be a good choice ..... but just a bit too high in cost, for my budget

 

[LSRFAQ]

[QUO
Edit: i just found that "diamond" can be a good choice ..... but just a bit too high in cost, for my budget [/QUOTE]

NaCl or KBr work fine from almost FAR IR to daylight and are cheap. KBr is used in IR spectroscopy for holding samples, but is very toxic. KBR is soft, you mix the sample with it and press it into a window with a hydraulic ram.

A NaCl window should be about 9$.

Steve

 

[Bluefan]

A few materials that are transparent around 3um: magnesium fluoride, calcium fluoride, sapphise, zinc selenide, silicon and germanium (as far as I know).