Laser pointer discussion. Read/write reviews of laser pointers and laser pointer companies. Learn about all types of laser pointers and lasers





Welcome to Laser Pointer Forums! If you are looking for a laser pointer or want to compare different laser pointer companies, you may want to check out the LPF Laser Pointer Company Database. The link will open in a new window for your convenience.








Green Laser Pointers by Category Blue Laser Pointers by Category Red Laser Pointers by Category
Yellow Laser Pointers by Category Violet Laser Pointers by Category Orange Laser Pointers by Category
Top Laser Pointers by Power - 1 Watt+ Top Laser Pointers by Power - 500mW+ Top Laser Pointers by Power - 250mW+
Laser Pointer Database High Power Laser Pointers Laser Pointer Diodes
Laser Technology Laser Pointer Parts Lasers by Wavelength
Top 10 Laser Pointer Companies Laser Pointer Company Database Visible Beam Laser Pointers


One laser store meets all your needs

























Go Back   Laser Pointer Forums - Discuss Laser Pointers > Lasers > Experiments & Modifications



LPF List of Laser Pointer Companies (link opens new window)



Reply
 
LinkBack Thread Tools Display Modes
Old 03-05-2014, 12:02 AM #1
bloompyle's Avatar
Gas Guru
 
Join Date: Apr 2010
Location: Nebraska, US
Posts: 4,176
Rep Power: 2458
bloompyle has a reputation beyond reputebloompyle has a reputation beyond reputebloompyle has a reputation beyond reputebloompyle has a reputation beyond reputebloompyle has a reputation beyond reputebloompyle has a reputation beyond reputebloompyle has a reputation beyond reputebloompyle has a reputation beyond reputebloompyle has a reputation beyond reputebloompyle has a reputation beyond reputebloompyle has a reputation beyond repute
bloompyle bloompyle is offline
Gas Guru
bloompyle's Avatar
 
Join Date: Apr 2010
Location: Nebraska, US
Posts: 4,176
Rep Power: 2458
bloompyle has a reputation beyond reputebloompyle has a reputation beyond reputebloompyle has a reputation beyond reputebloompyle has a reputation beyond reputebloompyle has a reputation beyond reputebloompyle has a reputation beyond reputebloompyle has a reputation beyond reputebloompyle has a reputation beyond reputebloompyle has a reputation beyond reputebloompyle has a reputation beyond reputebloompyle has a reputation beyond repute
Default Directly doubled 960 -> 480

That frustrating moment when you're initially just thinking of a way to directly double 960nm to 480nm ... and you start to build an OPA in your head....

So for chagrins, I'll post about it

The biggest issue here is that in a directly doubled setup, you risk sending an enormous amount of light, back to the semiconductor in use. Resulting in a "fried" laser diode.

In 808 -> 1064 -> 532, or 808 -> 946 -> 473, there is one commonality. All optics are HT@808nm. Meaning that anything 808nm will just pass through, and not reflect back into the laser diode. All other coatings in question, reflect 1064 and 532/473 on it's way back to the diode, meaning no light can harm the diode.

This is the issue I am trying to solve here. Though I ended up making it much more complicated than I needed to, by mentally developing a 960 -> 480 specific OPA. Though it was fun to do, and I hope it sparks some nice discussion

So you're going to start with a 960nm pump source (I was looking at a 4W c-mount). You're also going to need:

polarizing beam splitter (PBS)
front surface mirror (M1)
Pockel's cell with fast rise driver (<7ns) (PC)
Quarter waveplate (WP)
Faraday rotator, continuous wave (FR)
1x 10cm RoC mirror HT@960nm & 480nm (M2)
LBO gain medium
1x 10cm RoC mirror HR@960nm & HT@480nm (M3)



The 960nm light will initially be in a horizontal, or vertical polarization (we'll start with horizontal for this demo). This light will pass through the polarizing beam splitter (PBS) (make sure to orientate it like so). Currently, the Pockel's cell (PC) is down, so it will have no effect on the light currently. This light will continue in horizontal polarization.

The light will pass through the quarter waveplate (WP), and rotate the polarization to the right 45*, then the faraday rotator (FR) will rotate the polarization another 45*. Now the polarization is vertical.

The, now vertically polarized, light will pass through the first mirror, then the LBO. the LBO will double the frequency of the 960 (rather inefficiently). All 480nm light created will pass through the next mirror. The 960 will reflect back through the gain medium (creating more 480) and pass through the next mirror.

Still vertically polarized, the light will now hit the faraday rotator again. Rotating it ro the right, 45*. However, this means it's flipping back the same direction as the first polarization. Then the waveplate flips it backwards another 45*, to vertical still.

To explain this, place your hand in front of you, flat, palm down. Imagine there is a clock through your hand, and your thumb is touching the 9, and your pinky, the 3. Rotating your hand 90* clockwise places your thumb on the 12, and your pinky on the 6. Ok?

So, initially, your hand is palm down, like the light, horizontal. It passes through the waveplate. Now your hand rotates to the right 45*. So, your thumb should be at 10:30, and your pinky is now at 4:30. The faraday rotator does another 45*, so now your hand is in the vertical polarization, thumb on 12, pinky on 6.

When passing back through, the faraday rotator can only rotate in one direction. So when you're coming back through, it's going to be clockwise again, relative to the light. So to you, since it's traveling towards you, it is flipped (counter clockwise). So if it flips 45* counter-clockwise, it reverses the last rotation. Thumb at 10:30, pinky at 4:30. However, the waveplate beyond the rotator acts normally. Rotating the polarization clockwise again. So your hand is now in the vertical polarization. Thumb at 12, pinky at 6 O'Clock.

Due to the flipped polarization from the original orientation (horizontal) the PBS will bounce the light out at a 90* angle. This light will then go to a front surface mirror (M1). Then the PBS, and 90*, back into the laser cavity. It will do the same thing again, however, this time, once it gets passed the pockel's cell initially (before the waveplate, and faraday rotator) the cell will be turned on. So the light goes through the cavity like normal, flips from vertical to horizontal, gain medium, comes back, 45* one way, then 45* back, still at horizontal. The Pockel's cell, however, flips polarization by 90*. This makes the light vertical again, so that it hits the PBS, then front surface mirror, comes back, pockel's flips it to horizontal, pockel's turns off, and the process cycles like this continuously.

So, in conclusion!

This will maintain a constant amplification throughout the cavity, keeping only one polarization inside, allowing a constant gain within the cavity, and constant gain on 480nm, and cycling of 960nm

Complicated, yes, as well as expensive.... Though it's a fun concept to think about

Later folks! Time to relax now

Pretty little diagram



__________________
"These things we do.
That others may live."

405nm 500mW
442nm 15mW Melles Griot HeCd
445nm 1W
455nm 100mW LaserBTB
457nm Tunable OMNI 532
465nm Tunable OMNI 532
467nm 1.8W NDB7675
472nm Tunable Omni 532
473nm 2x 100mW Melles Griot lab heads w/ PSUs
476nm Tunable OMNI 532
488nm Single line 35mW
496nm Tunable OMNI 532
502nm Tunable OMNI 532
514nm Tunable OMNI 532
520nm 40mW MSV2
532nm Various pointers
543nm GreeNe 2mW
568nm ~20mW ArKr whitelight line
589nm 126mW PGL-III-C
594nm Rigel-6; 4.75mW + <1mW
604nm 2x <1mW multiline
609nm Ne Penning mixture Ar line from REO 612nm
612nm HeNe 1mW ML 4 line; Raman 6 line
629nm <1mW Raman 6 line
633nm 1-4mw red HeNe
635nm Raman 6 line
638nm 20mW single mode
640nm Raman 6 line
647nm ~10mW ArKr whitelight Kr line
650nm Raman 6 line
658nm LPC-826
685nm 20mW
808nm Modded NewWish pen


HeNe/gas reference thread

Last edited by bloompyle; 03-05-2014 at 01:07 AM.
bloompyle is offline   Reply With Quote







LPF List of Laser Pointer Companies (link opens new window)







Old 03-05-2014, 01:58 AM #2
crazyspaz's Avatar
Class 3B Laser
 
Join Date: Jul 2012
Location: IN, United States
Posts: 2,864
Rep Power: 1313
crazyspaz has a reputation beyond reputecrazyspaz has a reputation beyond reputecrazyspaz has a reputation beyond reputecrazyspaz has a reputation beyond reputecrazyspaz has a reputation beyond reputecrazyspaz has a reputation beyond reputecrazyspaz has a reputation beyond reputecrazyspaz has a reputation beyond reputecrazyspaz has a reputation beyond reputecrazyspaz has a reputation beyond reputecrazyspaz has a reputation beyond repute
crazyspaz crazyspaz is offline
Class 3B Laser
crazyspaz's Avatar
 
Join Date: Jul 2012
Location: IN, United States
Posts: 2,864
Rep Power: 1313
crazyspaz has a reputation beyond reputecrazyspaz has a reputation beyond reputecrazyspaz has a reputation beyond reputecrazyspaz has a reputation beyond reputecrazyspaz has a reputation beyond reputecrazyspaz has a reputation beyond reputecrazyspaz has a reputation beyond reputecrazyspaz has a reputation beyond reputecrazyspaz has a reputation beyond reputecrazyspaz has a reputation beyond reputecrazyspaz has a reputation beyond repute
Default Re: Directly doubled 960 -> 480

I...Wha...Bu.... *goes and bins some 450 diodes*


It is fun to think about. It makes sense, and is one of those things where it seems simple, but I'm sure would be a b@#$ and a half to do. I would love to attempt this, or see someone attempt this- are you planning to? Or is this just something you have been thinking about? Either way, it seems easier than the 460 system on Dr. Sam's site.

+rep for sure
crazyspaz is offline   Reply With Quote
Old 03-06-2014, 01:05 PM #3
Jmillerdoc's Avatar
Class 2M Laser
 
Join Date: Oct 2011
Location: SW OK USA
Posts: 899
Rep Power: 135
Jmillerdoc has a reputation beyond reputeJmillerdoc has a reputation beyond reputeJmillerdoc has a reputation beyond reputeJmillerdoc has a reputation beyond reputeJmillerdoc has a reputation beyond reputeJmillerdoc has a reputation beyond reputeJmillerdoc has a reputation beyond reputeJmillerdoc has a reputation beyond reputeJmillerdoc has a reputation beyond reputeJmillerdoc has a reputation beyond reputeJmillerdoc has a reputation beyond repute
Jmillerdoc Jmillerdoc is offline
Class 2M Laser
Jmillerdoc's Avatar
 
Join Date: Oct 2011
Location: SW OK USA
Posts: 899
Rep Power: 135
Jmillerdoc has a reputation beyond reputeJmillerdoc has a reputation beyond reputeJmillerdoc has a reputation beyond reputeJmillerdoc has a reputation beyond reputeJmillerdoc has a reputation beyond reputeJmillerdoc has a reputation beyond reputeJmillerdoc has a reputation beyond reputeJmillerdoc has a reputation beyond reputeJmillerdoc has a reputation beyond reputeJmillerdoc has a reputation beyond reputeJmillerdoc has a reputation beyond repute
Default Re: Directly doubled 960 -> 480

Crazy, I was just thinking about posting if this could be done and I found this post. I was thinking why you couldn't just use a doubling media to double one of the readily available single mode 940nm IR diodes available. I didn't realize it would be this complicated though. So your saying the problem with using the diode as the source is the light reflected back into the diode. Why not just use a very hefty diode but run it at something like 10% of its max Po? Not sure if that would make a difference or not. Thoughts? Basically I'm saying sans all the fancy polarization optics and use the diode directly and let the light reflect back into it but use it in such a way that your running the diode far below its max operating output. Could the IR diode then handle the back reflections? Granted your output wouldn't be as much but would it work without killing the diode?
Jmillerdoc is offline   Reply With Quote
Reply





Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On











Loading








Green Laser Pointers by Category Blue Laser Pointers by Category Red Laser Pointers by Category
Yellow Laser Pointers by Category Violet Laser Pointers by Category Orange Laser Pointers by Category
Top Laser Pointers by Power - 1 Watt+ Top Laser Pointers by Power - 500mW+ Top Laser Pointers by Power - 250mW+
Laser Pointer Database High Power Laser Pointers Laser Pointer Diodes






Privacy Policy | Advertising Disclaimer | Terms of Use


 


All times are GMT. The time now is 01:24 PM.


Powered by: vBulletin
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
Search Engine Friendly URLs by vBSEO
Privacy Policy | Advertising Disclaimer | Terms of Use
Copyright (C) 2017 Laser Pointer Forums, LLC