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ArcticMyst Security by Avery

Single mode 405nm

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Oct 30, 2012
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Hi,

Is there any single transverse mode 405nm laser diode. Power required anywhere within 30-100 mw.

I tried on ebay couldn get any which says its single mode. Found two :

1. Sony SLD 323A - No datasheet to verify if it is single mode
2. Sanyo dl7386-101hg - No datasheet to verify if it is single mode

Thank you. I want to use the lasers for confocal experiment and hence need a tiny spot so that I can focus using an u-objective
 





Blord

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Dec 24, 2007
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All 405nm diodes are single mode. The 405nm are used in the BluRay drives. Multimode diodes are useless for writing the discs.
 

Things

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May 1, 2007
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Not ALL 405nm diodes are single mode, but all the ones anyone here is likely to encounter will be.
 
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Jun 10, 2010
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Hi, Things.

I'm probably a minority of 1, so I mostly have to agree with you; but it happens that I want to do holography, and I want very short exposures. That means I need maybe 200 mW, not only single transverse mode but also as close to single longitudinal mode as I can get. (Working on that.) I'm here, and I have reason to be concerned about this issue, so it isn't quite 100% true that all of the violet lasers anyone here is going to encounter are singlemode. Frankly, I wish it were.

Here's a viewing screen that I made by spraying yellow-green fluorescent paint on a sheet of aluminum. (Even the camera sees yellow-green a lot better than it sees 405 nm.) The top pattern is from a Michelson interferometer on what I hope will eventually be my holography platform; the middle pattern is from another Michelson, but on the same table as the laser. The bottom pattern is from a pair of windows, about 25 cm apart, which are serving as a coherence test. (What I look for in the bottom pattern is the criss-cross effect that you can see in this image. If there are only lines, the coherence length is less than the spacing between the windows. If there are no lines, the coherence length is less than the thickness of the first [I think] window, or possibly less than the thickness of either one.)

http://www.jonsinger.org/research/p...c.2013.0906_violet-laser_crisp-lock-2.c14.jpg

On a good day, I can get this set of patterns to persist for well over a minute. If I'm using a 5x7.5 cm film or plate with a silver-halide emulsion, the exposure should be only a few seconds. ...I hope. I guess I'll find out when I'm further along.

Cheers --
jon
 

Blord

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For our hobby the 405nm diodes we used are single mode. There are multimode 405nm diodes. They are much more expensive and fall beyond our scope of handheld laser.

So you are right that there is more than only single mode 405nm diodes.
 




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