Hey, I need to purchase a beam splitter which is to bee used for both a laser diode (635nm) and a CO2 laser (10.6um). I have checked with different materials and those which work for long IR such as ZnSe isn't compatible in visible range. Please let me know about availability of any beam splitter with this characteristics. I prefer non polarizing plate beam splitter.
Thank you very much in advance!
Hi, ZnSe might in fact be a suitable material for the red laser diode too (it's the short-wavelength end of the VIS range that is strongly absorbed, hence the ZnSe's orange color). Red pointing lasers are often used in conjunction with CO2 lasers and ZnSe optics. Could you be more specific about which transmission/reflection ratios you need from the beam splitter?
Hey Lauri, thanks for the comment. The diode laser is just for alignment and any transmittance more than say 30% should be sufficient. Also I am sure that the transmission for CO2 beam will be roughly 50% for ZnSe beam splitter.
Hi Laury,
You may want to take a look at KBr. I know it works very well for IR but I do not
know about 632 nm. Best Denis Tremblay
Hello,
extending Lauri's comment it is needed to add that refraction index of ZnSe is ~2.6 at 630nm what means that you actually do not need any coating for proper reflection from surface at 45deg as you will have in average 0.2 reflection (0.1 and 0.3 for different polarizations). And 0.08 and 0.28 for CO2 for different polarizations what means that in case of polarized CO2 laser you can choose proper plate orientation (without any coatings) and have low loses for CO2 and quite good reflection for HeNe. (These values are for single surface; you need to square transmittance for double reflection from the plate when calculating losses.)
Hi Nikhil,
ever thought of BaF2?
Tranparency region is from 12µm down to UV.
Hi Nikhil,
ZnSe is a good candidate and I confirm that it transmits/reflects 635 nm with few loss. Beside it presents less inconvenients in day to day use than fluoride crystals for example which can be sensitive to temperature or to humidity for some of them.
My feeling anyhow is that you face some issues regarding ghost images from back surfaces on uncoated plate.
I join a summary of some rough calculations of the effect.
Patrick
Thanks for your valuable suggestions. Lauri and Gintaras, I see your point and I think uncoated ZnSe could be a good choice. Thanks for the diagram Robert, R2 and T2 aren't negligible indeed and I need to double check on the requirements. Between any suggestion where I can purchase uncoated ZnSe?
You could buy uncoated ZnSe for example from Thorlabs, ISP Optics, and Edmund Optics.
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