Red beam visible, no smoke or anything!?!!?!?!?

[brtaman]

After doing some super cooling tests on my burner diode, I decided to box it. (came out pretty nice , if anyone wants pics ill be more then glad to post them).

Well I turned it on in a dark room and the beam is visible??? I had never noticed this beforehand, so if the questions is completely noobish then just say. Are beams of red lasers visible when they are powerful enough???

I was always under the impression that a red beam is invisible (unless you have alot of moisture and smoke)...

This one is visible as is, and has made me a very very happy man

brtaman

 

[daguin]

Re: Red beam visible, no smoke or anything!?!!?!?!

After doing some super cooling tests on my burner diode, I decided to box it. (came out pretty nice , if anyone wants pics ill be more then glad to post them).
Well I turned it on in a dark room and the beam is visible??? I had never noticed this beforehand, so if the questions is completely noobish then just say. Are beams of red lasers visible when they are powerful enough???
I was always under the impression that a red beam is invisible (unless you have alot of moisture and smoke)...
This one is visible as is, and has made me a very very happy man
brtaman

One can NEVER post too many pics

The beam of a red laser is not invisible. It is just not as easily visible as a green. This is a difference in our eyes, NOT the beam. The more powerful the beam is, the easier it is to see. However, changing conditions (of the air) will significantly effect it. Even if you don't "add" any visualizers to the air, they are constantly changing. Just the act of packing up the cooling unit could effect the amount of "dust" in the air. You might not be able to "see" that there is more dust in the air, but it is there. With more dust in the air, there is more for the beam to reflect off of. The humidity changes with the weather, how long the door was open, and how long ago you showered.

Peace,
dave

 

[brtaman]

Re: Red beam visible, no smoke or anything!?!!?!?!

Hehe, thanks for the quick reply daguin!

Though there is some moisture in the air (natural), the room was not where the experiment was taking place and I dont think it was too dusty (though im not exactly a role model for house cleanliness ). I am very happy, as I thought that the red stays invisible unless there is massive smoke dust in the air...made my day actually hehe

I uploaded a pic of the box (there are 4 screws tightly securing it together so an internal shot is a bit out of reach as I have to run atm and I am also pretty lazy)

It runs on a DDL driver, its a 16x diode, runs at ~160 mA (so maybe the >200 mW on the box is bit far fetched hehe) when the pot is moved to the end, pretty fun, has an aizix module with the back plastic cut out(boy that was a pain in the a$$).

brtaman

 

[daguin]

Re: Red beam visible, no smoke or anything!?!!?!?!

Hehe, thanks for the quick reply daguin!

Though there is some moisture in the air (natural), the room was not where the experiment was taking place and I dont think it was too dusty (though im not exactly a role model for house cleanliness ). I am very happy, as I thought that the red stays invisible unless there is massive smoke dust in the air...made my day actually hehe

I uploaded a pic of the box (there are 4 screws tightly securing it together so an internal shot is a bit out of reach as I have to run atm and I am also pretty lazy)

It runs on a DDL driver, its a 16x diode, runs at ~160 mA (so maybe the >200 mW on the box is bit far fetched hehe) when the pot is moved to the end, pretty fun, has an aizix module with the back plastic cut out(boy that was a pain in the a$$).

brtaman

Well, as I said, MANY things will effect the amount of "dust" and moisture in the air (even in a very clean house).

It looks like you have a very nice, compact unit there.

Peace,
dave

 

[flogged]

Re: Red beam visible, no smoke or anything!?!!?!?!

DVD (red) LDs can be seen in a dark room. A little smoke/fog/haze makes the beam much more visible. It also helps to sight, looking down the beam, or looking back towards the laser (forward/backscattering while close to the beam).

A 16x diode using 160mA is probably putting out 100-125mW.. Unless you've got a laser power meter and a spectrum analyzer it's going to be hard to tell exactly what's happening when you chill the diode.

There are probably a few things happening to make the laser more visible as you cool it. First, laser diodes operate more efficiently at frigid temperatures. So, using a constant current driver (DDL) the laser will be kicking out more mWs (brighter) when cooled. As the output of the laser shifts to a higher frequency (when cooled) it also becomes more visible. It's possible you've cooled the diode to where its output is < 650nm (or even < 640nm) and this WILL make it more visible. The sensitivity of the eye changes quite a bit from 630nm (21%) to 660nm (6%) .. [ http://www.repairfaq.org/sam/laserioi.htm#ioicav2 ]. I've got some 15-20mW 635nm pointers, and the beams on these are as visible as a 60+ mW DVD diode (655 nm).

So cooling the diode will increase its brightness and decrease it wavelength - both will make the beam more visible.

Also, your cooled diodes should live longer.

{EDIT - so it's visible when you're NOT cooling it.. ooops}

 

[Switch]

Re: Red beam visible, no smoke or anything!?!!?!?!

Well, you can just put it this way, if the dot is as bright as the dot from a green laser , the beam will also be of the same brightness.

 

[Cyparagon]

Re: Red beam visible, no smoke or anything!?!!?!?!

Not true. The atmosphere scatters longer wavelengths more. Juxtapose violet and red. a 150mW red dot will be significantly brighter than the dot of a 50mW blu-ray, but the blu-ray's beam will be unparalleled.

 

[Chicxulub]

Re: Red beam visible, no smoke or anything!?!!?!?!

DVD (red) LDs can be seen in a dark room. A little smoke/fog/haze makes the beam much more visible. It also helps to sight, looking down the beam, or looking back towards the laser (forward/backscattering while close to the beam).

A 16x diode using 160mA is probably putting out 100-125mW.. Unless you've got a laser power meter and a spectrum analyzer it's going to be hard to tell exactly what's happening when you chill the diode.

There are probably a few things happening to make the laser more visible as you cool it. First, laser diodes operate more efficiently at frigid temperatures. So, using a constant current driver (DDL) the laser will be kicking out more mWs (brighter) when cooled. As the output of the laser shifts to a higher frequency (when cooled) it also becomes more visible. It's possible you've cooled the diode to where its output is < 650nm (or even < 640nm) and this WILL make it more visible. The sensitivity of the eye changes quite a bit from 630nm (21%) to 660nm (6%) .. [ http://www.repairfaq.org/sam/laserioi.htm#ioicav2 ]. I've got some 15-20mW 635nm pointers, and the beams on these are as visible as a 60+ mW DVD diode (655 nm).

So cooling the diode will increase its brightness and decrease it wavelength - both will make the beam more visible.

Also, your cooled diodes should live longer.

{EDIT - so it's visible when you're NOT cooling it.. ooops}

Where the heck did you get those? I've been looking for something like that for some time....

 

[daguin]

Re: Red beam visible, no smoke or anything!?!!?!?!

Where the heck did you get those? I've been looking for something like that for some time....

Just search "635nm" in eBay -- plain diodes, diodes in modules, diodes with drivers, all 635nm

Peace,
dave