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Do RPLs have IR filters?

laze_doctor

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According to one of our respected forum members, GooeyGus, they do not:

Every viasho hand held laser or RPL that I have seen does not have an IR filter, per se. That being said, the cavity and optics are designed such that no stray IR really has any way out. With blue you are dealing with quite a bit more pump power, so it is possble for a tiny bit to escape even with the good cavity design.
Questions: Is this accurate? Would it be as effective as a conventional IR filter (for a green)? I was under the impression that both greens and blues had a 2.5W pump diode, so how can blue be dealing with more pump power?
 

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It depends on the efficiency of the crystals. I really don't know how efficient the crystals of RPL's are. I know they've got a 2,5W pump diode but I'm not sure about the 473nm blues. Maybe you could ask Jack from Opto.
 

themandalorian

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Well didn't Yobresal show that after he put an IR filter over his 473nm the power dropped
 

laze_doctor

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Apparently it's accepted that the blues don't have IR filters, but there seems to be some confusion over whether the greens do. I might fire off an email to Jack.
 

john_lawson

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already did a few hours ago he should reply by today my blue rpl puts out about 42 mw and 2 mw ir at times
 

bootleg2go

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already did a few hours ago he should reply by today my blue rpl puts out about 42 mw and 2 mw ir at times
Hi John,
Thanks for contacting me about this.
All of the RPLs both green and blue have optical coatings which block IR, they do not have seperate filters. This is much better way to remove any stray IR, but is more expensive than using seperate filter. The reason this is better is that each additional surface that the beam has to go through degrades beam quality (especially with the very cheap filters that are commonly used). This causes more scatter and a larger beam. Also each surface even if multicoated will lose anywhere from 3-6% of the light through absorption, so eliminating stray IR by the use of coating on optical surfaces already present.
I have come across a few of the RPL blue lasers whcih for reason in the mfg. process must not have passed the IR tests and an extra filter was placed in them and they still passed all specs, but their power would have been reduced over what it would have been otherwise.
I do know that the older generic viasho protable lasers (and maybe even those made today, but can't say for sure as I've not had my hands on any of them in a couple of years), did not filter for IR.
I personally test each RPL for any IR leakage and any one which emits 1% more of IR to green never goes to a customer and gets reworked. With the premium pens pointers, this is tested and limited to no more than 4% and is typically 3% or less.

Thanks for telling me about this discussion John, I've gotta go now as I'm extremely busy this past few weeks and have an out of town visitor on top of all the work to get done.
 

daguin

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Thanks, Jack

I know that neither of the RPL's I owned (green and blue) had any significant IR output

Peace,
dave
 
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Hi John,
Thanks for contacting me about this.
All of the RPLs both green and blue have optical coatings which block IR, they do not have seperate filters. This is much better way to remove any stray IR, but is more expensive than using seperate filter. The reason this is better is that each additional surface that the beam has to go through degrades beam quality (especially with the very cheap filters that are commonly used). This causes more scatter and a larger beam. Also each surface even if multicoated will lose anywhere from 3-6% of the light through absorption, so eliminating stray IR by the use of coating on optical surfaces already present.
I have come across a few of the RPL blue lasers whcih for reason in the mfg. process must not have passed the IR tests and an extra filter was placed in them and they still passed all specs, but their power would have been reduced over what it would have been otherwise.
I do know that the older generic viasho protable lasers (and maybe even those made today, but can't say for sure as I've not had my hands on any of them in a couple of years), did not filter for IR.
I personally test each RPL for any IR leakage and any one which emits 1% more of IR to green never goes to a customer and gets reworked. With the premium pens pointers, this is tested and limited to no more than 4% and is typically 3% or less.

Thanks for telling me about this discussion John, I've gotta go now as I'm extremely busy this past few weeks and have an out of town visitor on top of all the work to get done.
Nice! Didn't know that, thanks :)
 




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