405nm Dichro's

[mliptack]

I'm still here! lol sorry haven't been in on PL for a few days, work always has a tendency to consume my life.

Regards,
Max

[bridge]

Hi all,
Pleasure to tell all of you, the 405nm dichroic is ready.
yes, pictures.
sorry for my tremble when take pictures.
best regards!
Bridge

[bridge]

sorry for degree, light dot on mirror are not best and stable.just quickly news pictures, .

[tocket]

Bridge! Mount the dichro at 45° in a spectrometer and record the transmission spectrum instead. Reflectance can be assumed to be roughly 1-transmittance. From the pictures it looks like it reflects significant amounts of blue and red.

[mccarrot]

If i'm correct the standard dichro's are coated on both sides.
Why should you coat a dichro on bith sides? I think it will only give you more loses on transmit.

Can you tell me if these dichro's are also coated on both sides??


I used to have 1 side coated dichros with better pass trough values, only those dichro's where terrible with reflect.

[keeperx]

agreed, the 405 reflection is wonderful, but it does look as if the blue and red are reflected.

now that may also be because the reflected beam is at 90 degrees to the camera and the main beam is traveling away from the camera..

[bridge]

yes.
first, the camara is 90 degree to the reflect line
second, as the degree is not 45 degree
third, for this coating, 92% pass of blue and red is very well, especially 45 degree not 0 degree, the blue one is near 405nm which need high reflect, the 650 is far away, coating is not easy for this working.
fourth, if we using smog and take pictures, you will get totally different result, as we not using smog and the light after carama ,from the beam before carama and after pass carama, you can see the brightness is about the same, if as you see that much reflection, the brightness will be large change.
Best regards!
Bridge

[keeperx]

what he said...

[allthatwhichis]

One thing I think we may have to look into is not mounting all of our lasers at the same angle to the dichros. I have noticed in my projector that 45 degrees is not the best angle for all my filters.

My reflect green dichro has a sweet spot for transmitting red and reflecting green and neither are 45 degrees. I first found the transmit red sweet spot and then mounted my red and then found the sweet spot for green reflection and mounted the green at that angle.

Then my reflect blue dichro has a sweet spot for transmitting green. The Red transmits well at all angles and the reflect blue seems to do well at all angles, so had to "tune" the angle for the best green transmittance.

Here is the final resulting layout. Granted, I do not have a meter to verify these are the sweetest spots, but by using vision, this is the most efficient layout I could find:

http://www.photonlexicon.com/forums/...&pictureid=289

Just a link as the picture is BIG.

O yea, there is the 660/635 dichro that needed all kinds of angle tweeking and it still is not that efficient. If you would like to see all of the angles tried, or at least pictures of the evolution of the angles, here is my album for the "box"
. http://www.photonlexicon.com/forums/album.php?albumid=8

[stanwax]

OK a final confirmation of numbers

I make
9 required for UK + extras I will order
16 required for US

PBS I will count up separately and edit this post

Rob