Welcome to Laser Pointer Forums - discuss green laser pointers, blue laser pointers, and all types of lasers



Laser Pointer Store

Review of the Yellow DPSS Laser Pointer

Joined
Nov 1, 2006
Messages
499
Likes
172
Points
43
This is a long page with at least 23 images on it; dial-up users please allow for plenty of load time.
You have no chance to survive make your time.


Yellow DPSS Laser Pointer, retail $199.00*
Manufactured by (unknown)
Last updated 03-01-11




This is a yellow SFDPSS (sum frequency diode pumped solid state) laser pointer that is designed to output 5mW (but actually outputs just over 0.9mW). It is made primarily from brass, covered with what I believe is a black baked enamel finish. It also has a gold-colored tailcap, bezel, ring around the barrel, and pocket clip -- these accents look very nice (classy!) on this laser pointer.

* The sender said that this is the amount he paid for it on Ebay in early-2011.


SIZE



Feed the laser pointer a pair of AAA cells (see below; the batteries are very likely included), and then you'll be ready to rock.

To use the laser pointer, just aim it at something you wish to point out, and press & hold the button on the barrel. Release the button to turn the laser pointer back off.






To change the batteries in this laser, unscrew the tailcap, and set it aside.

Tip the used AAA cells out of the barrel and into your hand, and dispose of, recycle, or recharge them as you see fit. Please do not under any circumstances flush them down a toliet or throw them into a salmon-filled stream or those tree-huggers might hunt you down and then beat the living tweedle out of you.


Insert two new AAA cells into the barrel, flat-end (-) negative first. This is the opposite of how batteries are installed in most flashlights, so please pay attention to polarity here.

Screw the tailcap back on, and be done with it.

Current usage measures 472.0mA on my DMM's 4A scale.




This is a laser pointer, not a flashlight meant to be carried around, thrashed, trashed, and abused, so I won't abuse it like I might abuse a flashlight in the name of science.
Lasers are meant to be loved, not punished.

In a 593.5nm yellow DPSS laser (pointer or larger size), there's a BIG near-infrared laser diode that generates laser light at 808nm, this is fired into a crystal containing the rare-earth element "neodymium". This crystal takes the 808nm infrared laser light and lases at 1,064 and 1,342nm (yes, deeper in the infrared!). This laser light comes out of the Nd:YV04 (neodymium yttrium vanadium oxide) crystal and is then shot into a second crystal (containing potassium, titanium, & phosphorus, usually called KTP) that roughly doubles the frequency to 593.5nm - the bright orangish yellow color you see. This light is then collimated (focused) by a lens and emerges out the laser's "business end". Just before the lens, there's a filter that removes any stray NIR (near-infrared) and IR (infrared) radiation from the pump diode and the neodymium crystal. You don't want that stuff in your yellow beam, trust me.


From a laser engineer who emailed me about this laser, comes the following text:

The technology behind the yellow laser is a bit more involved than in the green laser,
involving a process called sum frequency generation. It uses the same
components that the green laser has, but the coatings are much different.

There are two particular "tricks" in making a sum frequency laser. The
first is to get a single laser crystal (the Nd:YAG or Nd:YVO4) to lase
simultaneously at two different wavelengths, both 1064 nm and 1342 nm.
While we do this with gas lasers (Argon and Krypton) frequently, this is
pretty rare with solid state. The relative powers of the two have to
be in a reasonable range for the sum frequency process to work. The
two waves are introduced in to the KTP crystal, which generates the 593.5nm output.


This is why yellow DPSS lasers are so much more expensive than red diode lasers. Lots of itty bitty parts, and they all need to be very carefully aligned by hand. If the polarisation is "off", one or both crystals need to be turned.
With red diode lasers, you just slap in the diode and slap a lens in front of it.

This laser is not water-resistant, so please be extra careful when using it around sinks, tubs, toliets, fishtanks, pet water bowls, or other places where water or water-like liquids might be found. And you'll probably want to cover it up or otherwise get rid of it (such as by putting it in a pocket or bag) if you need to carry it in rainy or snowy weather.

This is a CDRH Class II laser device (measures 0.9875mW) although it's labelled as a CDRH Class IIIa laser.









Beam photograph on the test target at 12".
Measures 0.9875mW on a Sper Scientific Pocket Laser Power Meter # 840011.



Beam photograph on a wall at ~10 feet.

Those colored graphics that you see toward the left are my "Viva Piñata" posters, and that clock near the left-center that looks like it's made from wood is my Wooden Wall Clock.
You should also be able to see a Digimon plush (Greymon) almost directly below the clock.




Spectrographic analysis of this laser.



Spectrographic analysis of this laser; spectrometer's response narrowed to a band between 583.50nm and 603.50nm to pinpoint wavelength; which appears to be 594.92nm.



Spectrographic analysis of this laser; spectrometer's response narrowed to a band between
800nm and 820nm and sensitivity was enhanced to show the total lack of NIR emission from the pump diode. Actually, I hosed down that spectrometer quite thoroughly and still found no NIR line from the pump diode in this laser pointer!



Spectrographic analysis of this laser; spectrometer's input deliberately "overloaded" to show emission at 532nm and 671nm. Yellow laser line at 593.5nm was removed post-test because if I left it in place, it was so broad (due entirely to spectrometer overload) it didn't even look like a laser line -- its apparent spectral line width was at least 100nm at the baseline!!!




Spectrographic analysis of this laser; spectrometer's response narrowed to a band between 800nm and 820nm, spectrometer's sensor was hosed down thoroughly,and the laser's IR filter was removed before I could detect the 810nm laser line from the pump diode. This laser is not designed to be used without the IR filter, so this weak emission is really of no major concern.

USB2000 spectrometer graciously donated by P.L.




Beam cross-sectional analysis.

Image made using the ProMetric System by Radiant Imaging.






TEST NOTES:
Test unit was loaned to me & sent by a fan of the website and was received at 4:44pm PST on 02-18-11 (or "18 Feb 2011" or even "Feb 18 Twenty Double Sticks" if you prefer).

Since they wanted it back rather quickly, I sent it back shortly after writing this eval. and have appended the dreadful "
" icon to its listings on this website to denote the fact that I no longer have it available for additional comparisons or analyses.



UPDATE: 00-00-00



PROS:
Has a hefty, "not cheap" feel
Nice beam quality -- beam is exceptionally clean with no unwanted "nasties" (artifacts) in it
Uses batteries that are common and relatively inexpen$ive


CONS:
Not waterproof or submersible - but most pointers aren't. Will not figure into my rating
More delicate than directly-injected diode laser pointers/pointers. Again, will not figure into my rating
Power output is a bit on the low side - this is what nocked that last ½ star off


MANUFACTURER: Unknown
PRODUCT TYPE: Yellow SFDPSS laser pointer
LAMP TYPE: SFDPSS laser
No. OF LAMPS: 1
BEAM TYPE: Very narrow spot
SWITCH TYPE: Momentary pushbutton on/off on barrel
CASE MATERIAL: Brass
BEZEL: Metal; collimating lens inset into a hosel for it
BATTERY: 2x AAA cells
CURRENT CONSUMPTION: 472.0mA
WATER- AND URANATION-RESISTANT: Very light splatter-resistance at maximum
SUBMERSIBLE: NO WAY HOZAY!!!

ACCESSORIES: Unknown; but probably at least two AAA cells; possibly a presentation case
SIZE: 154mm L x 14mm D (not incl. power button)
WEIGHT: Not equipped to weigh
COUNTRY OF MANUFACTURE: Not known; though very probably China
WARRANTY: Unknown


PRODUCT RATING:



Update 03-01-11: Added a spectrographic analysis that I had performed earlier but had forgotten to add to this post.
 
Last edited:

anselm

New member
Joined
Nov 22, 2010
Messages
2,470
Likes
80
Points
0
See, now THAT is a laser you don't see every day!:wave:
Thanks for another great review, I'm glad that people who own "exoctic" lasers
actually send them to you to have them checked over.:)

I think I would too, if I had one.:D
 
Joined
Nov 1, 2006
Messages
499
Likes
172
Points
43
Joined
Mar 27, 2008
Messages
477
Likes
26
Points
0
Very cool. Inside the front aperture cap there should be a serial number. If it was sold from us after September 2009 I should be able to find out some details on it.
 
Joined
Nov 18, 2009
Messages
271
Likes
9
Points
0
In a 593.5nm yellow DPSS laser (pointer or larger size), there's a BIG near-infrared laser diode that generates laser light at 808nm, this is fired into a crystal containing the rare-earth element "neodymium". This crystal takes the 808nm infrared laser light and lases at 1,064 and 1,342nm (yes, deeper in the infrared!). This laser light comes out of the Nd:YV04 (neodymium yttrium vanadium oxide) crystal and is then shot into a second crystal (containing potassium, titanium, & phosphorus, usually called KTP) that roughly doubles the frequency to 593.5nm - the bright orangish yellow color you see. This light is then collimated (focused) by a lens and emerges out the laser's "business end". Just before the lens, there's a filter that removes any stray NIR (near-infrared) and IR (infrared) radiation from the pump diode and the neodymium crystal. You don't want that stuff in your yellow beam, trust me.
...
The technology behind the yellow laser is a bit more involved than in the green laser,
involving a process called sum frequency generation. It uses the same
components that the green laser has, but the coatings are much different.

There are two particular "tricks" in making a sum frequency laser. The
first is to get a single laser crystal (the Nd:YAG or Nd:YVO4) to lase
simultaneously at two different wavelengths, both 1064 nm and 1342 nm.
While we do this with gas lasers (Argon and Krypton) frequently, this is
pretty rare with solid state. The relative powers of the two have to
be in a reasonable range for the sum frequency process to work. The
two waves are introduced in to the KTP crystal, which generates the 593.5nm output.[/i]
I liked ur review, and i understand that you wanted to keep it quite informal and readable, and i know u used the roughly, but, i dunno...I dont feel at ease to read "double" in there. This is a frequency sum process...and lets say a person that is new to the hobby knows nothing about either of the processes will get kind of confused with ur doubling and then saying "the engineer stated frequency sum" and so on.

Im not meaning to trash ur review! It was a very good review actually with lots of info and emission spectrums (+1 for the whole review actually).

But i dunno if anybody felt it shouldnt say double in there...a "mashes those 2 awesome Neodymium wavelengths up and the result is that eye-pleasing gold beam" in my opinion would be more correct and also quite informal...


Sorry if this looks rather depreciative comment, but i dont really have those intentions.

Keep up the good reviews! :D
 




Top