A UV filter

[Ablaze]

Hello everyone.

My Chinese supplier has just asked me if I wanted to add a UV filter to my laser in order to make them less likely to fail. I've tried to think of a reason, but try as I might I can't see how a UV filter would help.

So my question is this: Can UV light damage a laser diode? Is there any reason to ever put a UV filter on a laser diode?

 

[jimdt7]

I dont know why a UV filter will help a laser diode !
What color is your laser ?

 

[LaZeRz]

Wtf? No lasers produce excess UV except for UV lasers. Maybe he meant IR filters for greenies?

 

[DrSid]

Would be interesting to know what laser it was .. what color and power ..

 

[jake642]

There just trying to scam you, take your money elsewhere.

 

[rhd]

There just trying to scam you, take your money elsewhere.

That, or they're inept. Probably confused about the difference between UV and IR. That doesn't sit will, if they're actively selling lasers.

 

[strik3]

also a filter will not stop a laser from failing

 

[Ablaze]

Well, he is not saying that the laser actually produces UV. He is saying that a UV filter may help to protect the diode.

I think that perhaps he is using it as a dust filter, and that you may as well filter against UV as using a clear piece of plastic. That is the best explanation I can come up with.

Would be interesting to know what laser it was .. what color and power ..

He is purposing to apply this filter to any laser of any color that I order in the future. What I happen to be ordering now is a 25mw 470nm diode.

Thank you for your responses. I just wanted to make sure I wasn't missing something obvious. I told him to go ahead and apply the UV filter if it makes him happy, since he isn't planning on charging me more for it.

 

[DrSid]

Well the laser will have optics .. no need for dust filter. Also 470nm is pretty close to UV, UV filter may already be kicking in on this wavelength, lowering the output. It's real mystery.

 

[123splat]

Most High quality lasers already have a UV filter. It is also called a GLASS lense. Soda-silicate and Boro-silicate glass (any of you out there have oldfassioned Glass eyeglasses) are excellent UV filters. That's why UV lamps have QUARTZ glass lenses (SiO2), as quartz doesnt block/absorb the UV energy. The blue/purple coating on your Black light is not a UV filter. It is used to absorb the white light (everything but blue/purple) generated (usually) by Mercury Vapor ionization..... But pretty useless to specify a UV filter on any laser, as the only ones creating UV, or close to, do so intentionally.

 

[Ablaze]

Thank you for your input 123. I had not considered that he might simply be offering to use a glass lens. It would kind of make sense.

 

[DrSid]

Most High quality lasers already have a UV filter. It is also called a GLASS lense. Soda-silicate and Boro-silicate glass (any of you out there have oldfassioned Glass eyeglasses) are excellent UV filters. That's why UV lamps have QUARTZ glass lenses (SiO2), as quartz doesnt block/absorb the UV energy. The blue/purple coating on your Black light is not a UV filter. It is used to absorb the white light (everything but blue/purple) generated (usually) by Mercury Vapor ionization..... But pretty useless to specify a UV filter on any laser, as the only ones creating UV, or close to, do so intentionally.

It's not so simple with the glass blocking UV .. depends on UV type .. citation from wiki:

Ordinary glass is partially transparent to UVA but is opaque to shorter wavelengths, whereas silica or quartz glass, depending on quality, can be transparent even to vacuum UV wavelengths. Ordinary window glass passes about 90% of the light above 350 nm, but blocks over 90% of the light below 300 nm.

 

[123splat]

the good doctor is correct, but it is the shorter wave lengths that do the damage.