can a DPSS Laser replace a HeNe ?

[yakari]

Hi,

is it true that some DPSS Laser could even replace a HeNe Laser when the factor coherence lenght counts?

Some companies even claim to sell single longitudinal mode DPSS Laser with > hundreds of meters coherence length.
This sounds too good to be true. But if it does it would be more than great, because i am tired of the multi longitudinal modes of my 3mW HeNe Laser.
For my application (a long range interferometer) I don't need high output power, 3 to 10mW would be fine.

Does any one know such a Laser? If yes, what is written on the price tag for a low power one?

Thank you in advance for your help!

[Jem]

Hi yakari...

And welcome to Photonlexicon. Yes a DPSS laser can replace a HeNe laser for the application you are wanting.

However, you need a 'special' DPSS laser as most aren't SLM. I would suggest something like a Coherent C315m, this is a very stable laser, it's SLM and has a coherence length of many meters. They are quite expensive, but is you're only needing low power try looking for a 20mW one.

Another good laser is the JDSU Microgreen, although the beam profile isn't as good as the C315m, it is SLM and has good coherence length. Some of the small B & W Tek laser also meet the characteristics you require.

One other thing... The lasers I've mentioned above are green lasers operating at 532nm. There are some low power red diode SLM lasers, in fact quite a few diode lasers operate in SLM at low power. The only problem is that you would need to have a means of testing for SLM and that can be expensive.

I think there's a good chance that someone will see this thread and be able to offer to test a low power red for you. I'm thinking of Dave Battin or Phil Bergeron et al

Hope this helps

Cheers

Jem

[Junktronix]

Can you work with a green laser (532nm)? If so, you can find JDSU Microgreen lasers 10-20mW for <$500. They have coherence length of a meter or better. Coherent 315M lasers at 100mW have >50m coherence length, but sell for around $1500-2000. The ultimate would be a Lightwave 142 which has a reported coherence length >1000m! but they are hard to find and very expensive.

If you need red, it is possible to stabilize a single mode laser diode, but it requires very stable temperature control and I'm not aware of a commercial version.

[taggalucci]

Dingle more?! Single mode perhaps