New Gadget - 355/532/1064 Q-Switched YAG

[paul1598419]

Like I said, it was an educated guess as your spectrometer isn't calibrated. I do see what you are talking about in the pump energy necessary to get the dye to lase. I have been reading Koechner's book in order to learn enough to build a ruby laser. Of course, I am learning much more than just what is needed to build that one laser. I have learned a great deal about Nd:YAG lasers in the process. And a whole lot of information I may never use again.

 

[diachi]

BIOTCH! Send me that thing! Cruel, cruel, cruel man.... Beautiful.

:crackup: :crackup:

Like I said, it was an educated guess as your spectrometer isn't calibrated. I do see what you are talking about in the pump energy necessary to get the dye to lase. I have been reading Koechner's book in order to learn enough to build a ruby laser. Of course, I am learning much more than just what is needed to build that one laser. I have learned a great deal about Nd:YAG lasers in the process. And a whole lot of information I may never use again.

Agreed, definitely not a precise measurement. I need to dig through the spectrometer thread and dig up some better software or a newer version of what I have, that'd certainly be helpful.

Better to know stuff you'll never use than not know it and need to use it! :beer:

Still need to give that book a read myself, I'm sure I'd find even more use for the information within now that I'm moving on to more complex things.

 

[paul1598419]

I got a hardcover copy and I highly recommend it. It is full of mathematical equations that make more sense out of the statements than leaving them out would. At least for me. Math is the language of physics and to understand it is to understand the subject. You can't truly have a complete understanding of physics without the math involved.

 

[styropyro]

That's awesome that you are getting the dye to lase! I wouldn't have expected that to work so well in your setup.

As for the broad spectral width of your output, this is typical of organic dyes in a free running setup like you have. The large bandwidth actually becomes very useful in certain applications. If you throw a prism or gratings in your lasing cavity, you can dramatically shrink the spectral width of the output, as well as tune the emission wavelength. According to wikipedia, the dye Rhodamine 6G can be made to lase from 570nm all the way to 660nm using methods like this!

The coolest effect from a medium with a large spectral bandwidth is that you can use it to make incredibly short pulses. This is an effect of Heisenberg's uncertainty principle (in time and energy) where a large uncertainty in energy (a wide range of frequencies) corresponds to a well defined time interval (a very short pulse). IIRC the first lasers producing femtosecond scale pulses were organic dye lasers. A femtosecond is INCREDIBLY short, 1fs= 0.000000000000001s

And for the record, the time-energy uncertainty isn't fully accepted in physics as of now, but the same effect in fast-pulsed lasers can be described with fourier transforms and classical electromagnetic waves.

 

[diachi]

That's awesome that you are getting the dye to lase! I wouldn't have expected that to work so well in your setup.

As for the broad spectral width of your output, this is typical of organic dyes in a free running setup like you have. The large bandwidth actually becomes very useful in certain applications. If you throw a prism or gratings in your lasing cavity, you can dramatically shrink the spectral width of the output, as well as tune the emission wavelength. According to wikipedia, the dye Rhodamine 6G can be made to lase from 570nm all the way to 660nm using methods like this!

The coolest effect from a medium with a large spectral bandwidth is that you can use it to make incredibly short pulses. This is an effect of Heisenberg's uncertainty principle (in time and energy) where a large uncertainty in energy (a wide range of frequencies) corresponds to a well defined time interval (a very short pulse). IIRC the first lasers producing femtosecond scale pulses were organic dye lasers. A femtosecond is INCREDIBLY short, 1fs= 0.000000000000001s

And for the record, the time-energy uncertainty isn't fully accepted in physics as of now, but the same effect in fast-pulsed lasers can be described with fourier transforms and classical electromagnetic waves.

Yeah, I was pretty surprised too! Got the concentration right first time and everything, must have been luck!

Thanks for confirming! Yes, I've been doing a lot of reading today about dye lasers and that's one of the things I've been seeing a lot of, different configurations for tuning dye lasers.

I think I'm going to order one or two proper quartz cuvettes and start ordering in more optics/mounts/maybe a breadboard, there's so much I want to try out! Different pump configurations, output tuning, all of that fun stuff! Going to take some time to gather all of the necessary components.

Cool! I seem to recall having read that somewhere before about the pulse width. Might have been you that mentioned it in another thread. Learning all sorts over the last few days!

@Paul, I've got a PDF copy of that book. I still need to actually sit down and read it though. I prefer paper...

 

[paul1598419]

I prefer text books over reading online. Maybe it is just what I've become used to over these many years, but after I have used (read) a text book it then becomes a reference book for me.

 

[diachi]

I prefer text books over reading online. Maybe it is just what I've become used to over these many years, but after I have used (read) a text book it then becomes a reference book for me.

I've always been that way too, the only exception being the Kindle with the e-paper, those I don't mind so much. I still prefer paper though, especially old books, they have a nice smell. :crackup:

Agreed, don't throw that stuff away! I found a bunch of books at the dump last year, what a waste! There were thousands of them.

Update to the dye laser! Increased the dye concentration and now I can get proper pictures/video of the colour. Turns out there was some 355/532 getting through the weaker solution which was messing with the camera resulting in it seeing a sort of greenish yellow.

 

[paul1598419]

That looks much better. I love old books too. I had an 1889 edition of Grey's Anatomy that I only paid $40.00 for back in 1989. It got lost among the moves over the years. I lost more books in moves and break ups than anyone ever should have to.

 

[diachi]

That looks much better. I love old books too. I had an 1889 edition of Grey's Anatomy that I only paid $40.00 for back in 1989. It got lost among the moves over the years. I lost more books in moves and break ups than anyone ever should have to.

The oldest one I have is a book titled "Great Sea Stories", dated 1950 with a copyright dating to 1921. It's one of the ones I rescued from the dump, oddly enough it has the best "book smell" of all the books I own.

I rescued so many books from the dump that I had to buy a bookshelf for them. Found so many good books, even found "The Lithographer's Manual". There's probably hundreds more amongst the thousands that I didn't manage to find that I'd enjoy.

 

[paul1598419]

I don't understand people throwing books away. They can be donated to many organizations that will even give you a tax break on them. I have gone into used book stores and browsed for hours before. That is where I got that copy of Grey's Anatomy.

 

[Laserbuilder]

I've missed this thread.. Very cool laser! Maybe one day I'll start the project of the big green laser with CW lamp pumping.

 

[diachi]

I've missed this thread.. Very cool laser! Maybe one day I'll start the project of the big green laser with CW lamp pumping.

Thanks Laserbuilder! :beer:

Managed to get the output of the dye collimated, still far from ideal but it's a big improvement over what it was. My new, proper dye cell helps get a cleaner beam out.

Imgur Album here: https://imgur.com/a/VpmubOn

Hopefully I can get some beam shots later when it finally gets dark outside!

Edit:

If anyone finds any great deals on optics/mounts could you let me know? Looking for kinematic mirror mounts, rectangular lens mounts (for the dye cell), round lens mounts, PCX lenses for a telescope, short FL PCX for pump focusing and short FL cylindrical for pump focusing. Some AR@532 and HR/OC at 570-620nm mirrors would be nice too... Wouldn't mind a nice blazed diffraction grating for wavelength tuning either...

 

[ArcticDude]

Thanks Laserbuilder! :beer:

Managed to get the output of the dye collimated, still far from ideal but it's a big improvement over what it was. My new, proper dye cell helps get a cleaner beam out.

Imgur Album here: https://imgur.com/a/VpmubOn

Hopefully I can get some beam shots later when it finally gets dark outside!

 

[diachi]

Hah! Hey, at least you have that awesome RGB handheld!

 

[paul1598419]

Sure, what blaze angle would you prefer on the grating and would it be okay if I ran it up there to you this weekend? :crackup:

 

[diachi]

Sure, what blaze angle would you prefer on the grating and would it be okay if I ran it up there to you this weekend? :crackup:

Surprise me! And sure, supposed to be decent weather this weekend! :crackup: