Blue Diode, Dicro Reflector.

[tommylee333]

What color dicro do I need to reflect my blue diode, while still passing the red and green thru It, and Where Do I Get One?
I have several of the ones that reflect red, and one that reflects green but neither one of them are working right for the blue.
I'm rearanged my laser and I changed the diode order I now have the blue closest to the mirror befor I had It the fatherst from the mirror, then the greer reflected and the red reflected, but now that I changed the order I can't get the blue to reflect good and the red and green are a lots dimmer.
I originally had the blue shinning straight thru to the mirrors, and the green was reflected thru a dicro, then the red reflected thru a dicro, but now that I changed the order blue first, red 2nd, and green shining straight thru to the mirrors,I have lost most of my blue and the green Is a lots dimmer.
I am using the reflector that I was using for the geen to reflect the blue but It's not working right.
thanks for any info and God bless.

[cfavreau]

Hi Tommy,

Generally I have seen the dichro's specificed as reflect X pass X so you will need to find one that reflects blue and passes red/green as you say (I might be wrong about this... someone for sure will correct me ) I found all of the ones I have currently in junk LCD projectors that use 3 LCDs. You can also buy them off of EBay or from places like Edmunds or Thorlabs.

Kind of like the ones at this link:

Pack of 10 RGB Laser Dichroic Mirror/Pass Red,Green and Reflect Blue/445nm~635nm | eBay

You probably should look around as I just did a quick search and pasted the first good item I found.

Note that it is specified to Reflect Blue and Pass Red,Green. Sometimes they are specified to reflect a particular wavelength band. These would probably be more specialized so for instance you can combine 2 blue lasers such as 405, 455, and/or 488 or something like that.

Also interesting to note is that you can also use a PBS cube (Polarizing Beam Splitter) to combine lasers. Usually people use these to combine 2 laser diodes of the same color/wavelength.

I put the strongest laser (usually blue) in the position where it passes through the most mirrors/dichros. This way at the very most you will just need a regular first surface mirror. Red is usually the weakest although green can also be. I try to minimize the loss from reflection.

, Chris F.