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single mode laser

abikutn

abikutn

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Hello guys,

I am a research student, my research is based on Confocal Imaging.

Therefore I am quite interested in only single-mode lasers.

I tried thorlabs and newport, but the rates seems to be over-rated.

Can you guys please suggest me some sites where I can find single-mode diode lasers for reasonable price.

Also, one more question , Does single-mode have anything to do with special lasers such as 532nm (green ) or 589nm ( yellow ) or 593nm(orange').

Thank you ...
 





How much power do you need ? How much money you have ?

You can have red diode single mode laser at about 200-300mW, we are talking few dollars, they are from DVD burners.
Then you can have 405nm single mode laser at about 700-1000mW, about $100 with driver and all, they are from BRD burners.
Greens mostly come as DPSS, at powers from 5mW (few dollars) to 1W ($1000).
They are mostly single mode, but the higher power ones usually use larger crystals and have lots of submodes, and the mode spectrum changes all the time. Most presents are usually high modes like TEM10, TEM11.
589 and 593 are exotic wavelength, such lasers can use special constructions and are in another price level.
 
And you have the single mode blue diode. The power can reach to 300mW and cost $40.

Nice sum up, Dr Sid :beer:
 
DrSid said:
How much power do you need ? How much money you have ?

You can have red diode single mode laser at about 200-300mW, we are talking few dollars, they are from DVD burners.
Then you can have 405nm single mode laser at about 700-1000mW, about $100 with driver and all, they are from BRD burners.
Greens mostly come as DPSS, at powers from 5mW (few dollars) to 1W ($1000).
They are mostly single mode, but the higher power ones usually use larger crystals and have lots of submodes, and the mode spectrum changes all the time. Most presents are usually high modes like TEM10, TEM11.
589 and 593 are exotic wavelength, such lasers can use special constructions and are in another price level.
Click to expand...
Dr Sid,

Power requirements should be anywhere between 30-80mW.

I might need 5 different single-mode diodes.

405nm,450nm,532nm, 635nm,670nm

Money should not be a problem. I should be able to manage around $50 for each if possible ... special lasers are at a different price level I agree. That can be taken care by my school funds.

Since I am doing confocal imaging, single transverse mode is known to given a very tight focus and great collimation compared to multi-mode lasers diodes.

Abhi
 
Problem is you can have single mode diode lasers for red and 405nm. You can have multimode for 445nm. You can have some IR. And that's it.
You can have cheap DPSS green (under $50).
Any other wavelength is different story. It will cost hundreds and thousands.
That 445nm is available in high power, 1W and more .. if you only need 100mW you could mask the beam using peephole .. that would improve the beam characteristics.
You could go RGB with 635,532 and 455. That will actually give rather good approximation of standard RGB space. Or you could replace 445nm with 405nm .. which would get you possibly better beam, with blues a bit off.
Other colors are out of your reach, unless you get very lucky.
 
Yeah I can do with 405nm and 635 , 660 and probably one 532. Sounds good.

And one last question , which is the best place to buy these lasers from. Any trusted online sellers ? I tried EBAY, but all the laser diodes come from china, my professor is not all tat happy with that, he says thy may put in some other laser diodes apart from what they claim to send.

Please let me know good website where I can buy them from.

Best,

Abhi

PS: Also, dont you guys think laser diodes in sites such as thor labs is over-rated. Its way too much thy quote for each diode than what can be found on ebay or other places.
 
With e-bay it really depends on the individual sale. Same with Chinese. There are even respected Chinese shops. But best way is usually buying from respected member of this forum. Basically everything can be bought here, just see buy/sell section. For the rest we can tell you what Chinese sellers to buy from, and which you should avoid. But first try the buy/sell section, and don't forget to read stickies. Also note that users here have reputation rating, so you can tell who is new, who is good, and who will rob you (well, that you can't because those people are usually banned fast).
 
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Good. I will try again on ebay then and post the sellers names here just in case.
Also I tried this https://sites.google.com/site/dtrlpf/ and I tried to PM him with the address DTRLPF@gmail but it says not recognized. Anyone got his new contact please feel free in sharing.

Thanks a lot
Abhi
 
Hello guys ,

I have been trying out my luck shopping for single-mode laser diodes online, so far my progress is :

450nm : OSRAM PL-450B. ( Single transverse mode )

I am still continuing my research on this shopping lasers.

I have come across : http://www.oe-company.com/products/opnext/visible/ode2_071_hl63133dg_Rev1.pdf

I have a question in this spread sheet : What does TE mode oscillation mean ? Does it also mean single transverse mode ?

Please clear my doubt on this :)

Thanks ...
 
TEM is an acronym for Transverse Electromagnetic Mode.

"Single-mode" lasers operate at the lowest TEM, which is "0,0". Thus, "TEM00". The across-the-beam intensity profile of a TEM00 laser beam has a "Gaussian distribution":
200px-Gaussian_distribution_thick_lines.svg.png


Among other beneficial qualities the TEM00 mode happens to be the lowest divergence mode.

This Wiki article should help get you started with modes, also search the forum for laser modes:

Transverse mode - Wikipedia, the free encyclopedia

From the Wiki article linked above, this image showing the distribution of energy across the beam.

320px-Laguerre-gaussian.png


[Note that it is possible for more than one mode to operate simultaneously in a laser. I once had a "misfit/broken" multiwavelength HeNe laser (that was given to me at a laser conference by the manufacturer as it was useless to them) that only put out around 1 milliwatt, but that output consisted of a green TEM00 mode superimposed with an orange TEM01 mode, giving the beam spot the odd appearance of some kind of "gas planet".]

Good luck with your project!

T.
 
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