Review of a Rigel Yellow Laser Pointer

This is the Rigel, a yellow DPSS laser in a pen-style body. This is only the second yellow laser I've seen; this was the first, and that one was received in very late-summer 2004.

It generates an amberish-yellow beam, measured spectrographically at 592.95nm (5,929.5Å); just a bit longer in wavelength than the sodium line at 589.2nm (5892.0Å). The color could best be described as a "very strong urine yellow"; though there are probably some more gentle terms that could be used to describe the color - like...er...uh..."sunset yellow".

The output power is stated as "0.6mW to 2.0mW"; this was measured in this particular unit at 1.8312mW.

It uses a mechanism similar to that used by green laser pointers: an infrared laser diode is fired into a crystal of material that lases at two longer wavelengths in the infrared, who's light is then fired into a frequency-doubling crystal, producing the yellow laser beam you see. This is known as DPSS (Diode Pumped Solid State).

It comes in a brass body, and feeds from two AAA cells.


SIZE



To use your shiny new (or corroded old) Rigel, first peel off the orange plastic piece off the "business-end", and install two AAA cells (see directly below) that you furnish yourself.

At this point, just aim it at something you wish to point out, and rather firmly press & hold down the button on the barrel for as long as you need the laser spot.
Release the button to turn the laser pointer back off. Yes, it really is as easy as that.

It comes in a white cardboard box with a foam insert that the laser fits into; and although in and of itself this is not a storage case, with minor modification to the foam, it will fit many storage cases designed for green DPSS lasers. Otherwise, just store your Rigel in a clean & dry location, and it should not give you any guff.





To change the batteries in your Rigel, unscrew and remove the tailcap, and set it aside.

Tip the two used AAA cells out of the barrel and into your hand, and dispose of, recycle, or recharge them as you see fit.

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 475mA on my DMM's 4A scale.



There is a sticker on the box with the following text on it:





This is a laser pointer, not a flashlight. So I won't administer the more abusive tests on it that I might mete out on a flashlight.

Yellow diode lasers are a lot different than those common red lasers you see all the time.

In a 640nm red laser pointer, there's a red-emitting diode and a lens to collimate (focus) the beam.

In a 593.5nm yellow DPSS laser (pointer or larger size), there's a BIG 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 unit is not waterproof or submersible, so please try not to drop it into water or water-like liquids.

The end cap can be unscrewed to facilite cleaning of the lens; however this also removes the IR filter. This was evident because a thin square of bluish-green glass was seen inside the end cap. Here, let me show you with a photograph...snap...flash...click..and it's off to the Fotomat we go:



The amount of IR radiation emitted by this laser without the filter is surprisingly small; please see the third spectral analysis chart on this web page to see for yourself.
Normally I'd raise a stink about the IR filter being easily removeable by the end-user, but the amount of IR radiation emitted in this case is SO LOW, I don't feel the need to make a big issue of it.

The Rigel is true CW (continuous wave), not quasi-CW or pulsed. I verified this two ways: I rapidly waved it around to see if a broken line appeared (it did not), and I tested it with an oscilloscope to detect pulsed operation at faster speeds than an optical detection method can reveal, and again, found no evidence of pulsed operation.

I've noted that the button on the Rigel is harder to press than it is on all other laser pointers I've used to date. This is not necessarily a bad thing, but it is noticeable.

This is a CDRH Class IIIa laser product, so it is kosher for me to call it a "pointer", rather than a "module".


The warranty is rather specific: in the instructional material furnished with the laser is the following:

The unit is guaranteed to operate within specifications for 6 months from the shipping date, provided that:

- No modifications have been made to this unit.
- The unit has not been disassembled or tampered with.
- The unit was not dropped or subjected to excess shock or static electricity.
- The original instructions and warranty with serial number is retained.
- The unit is not operated from any power source other than 2 type "AAA" 1.5V Alkaline batteries.










TEST NOTES:
Test unit was purchased from Laserglow Technologies on 07-09-07, and was received on 07-13-07.








UPDATE 07-14-07:
Power output measures 1.6524mW when this laser is fed with known-new Energizer L92 lithium AAA cells.
According to the warranty info, I really need to get those lithiums out of there!!!





UPDATE 08-25-07:
I have decided to derate this product ***SLIGHTLY*** because the button is a bit harder to press on than the buttons of all other lasers I've tested. It still stays in The Trophy Case, however its rating has been changed from 5 stars to 4½ stars.




UPDATE: 10-27-10
I converted this eval. to BBCode so that I could post it on a couple of BBSs about lasers & lights.






PROS:
Uses batteries that are common and relatively inexpensive
Unique, attention-getting color that's radiant and unusual for a handheld laser
Beam is "clean", with no visible speckling or artifacts around it
Unique, attention-getting color...o wait I said that already.


CONS:
Button is harder to push than any other laser I've used.
Fragile interior construction - like all DPSS lasers. Will not figure into my rating
Not water-resistant - but most other DPSS lasers aren't either. Will not figure into my rating







MANUFACTURER: Unknown/TBA
PRODUCT TYPE: Yellow-emitting laser pointer
LAMP TYPE: DPSS laser
No. OF LAMPS: 1
BEAM TYPE: Very narrow spot; it's a laser, remember?

SWITCH TYPE: Pushbutton momentary on/off on barrel
CASE MATERIAL: Brass
BEZEL: Metal; has aperture (hole) for laser beam to emerge
BATTERY: 2x AAA cells
CURRENT CONSUMPTION: 475mA
WATER RESISTANT: No
SUBMERSIBLE: No
ACCESSORIES: None
WARRANTY: 6 months




PRODUCT RATING:

Nice review man!

Thanks for info's!

(one year later) lol!

If I remember correctly phoenix77 got one with 20mW output.

What's up with all the necroposting recently? That said I'm glad this thread was bumped since there's a GB in the works with this laser as one of the options.

Weird how nobody commented on this review when it came out.
Looks like TLM put some effort into it!

"very strong urine yellow" LOL