Review of Optotronics RPL-Blue-20 Laser

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The_LED_Museum

*Retired*
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Federal Way WA. USA
Since not everybody can access my website, I'll present this here:

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Optotronics RPL-Blue-20 Laser, retail $1,049.00 (www.optotronics.com...
Manufactured by (Unknown) for Optotronics (www.optotronics.com
Last updated 04-14-07

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(In reference to the box I found in my locked parcel locker at 1:24pm PDT on 04-04-07):
{sung like the Foreigner song "Feels Like the First Time"}

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This is a blue DPSS (diode pumped solid state) laser that is advertised to output no less than 20mW of laser radiation at 473nm in the blue part of the spectrum.

It comes in a cylindrical aluminum body, and uses one 18650 rechargable lithium-ion cell for power. It also has all of the safety features required for a CDRH Class IIIb laser product in the USA, except for the turn-on delay and security dongle. But it has a "system armed" indicator, something only seen on only one other small laser I've used.


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SIZE



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Feed the laser a freshly-charged 18650 rechargable lithium-ion cell (see below), and then you'll be ready to rock.

To use the laser, insert the interlock key into the end of the tailcap, turn it 90° clockwise and then remove it, slide the beam shutter on the front of the laser toward the center, press & release the red button on the side of the barrel, and THEN you'll get your blue beam. A small red LED comes on as soon as the button is pressed and then released. This is the laser emissions indicator.

Release the button to turn the laser back off.

Intermittent (momentary) operation is also available by pressing the button more lightly (before it clicks) and holding it that way for as long as you need the laser beam energized. Releasing the button turns the laser off.

When you are done using the laser, insert the interlock key and turn it 90° counterclockwise and then remove it.

All of this "rigamarole" is so that the laser complies with CDRH Class IIIb requirements.

When the interlock key is in the "on" position but the button is not pressed, the LED in front of the switch glows green; this serves as the "system armed" indicator. This is a feature I've only seen on one other small laser I've used.

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Here is the key interlock on the laser's tailcap. See that arrow? The little projection or tit on the outside of the key's barrel should be oriented so it fits into the notch the arrow is pointing to. In this photograph, the laser is turned completely off.

*** VERY IMPORTANT!!! ***
You must turn the keyswitch to the "off" position when you are finished using the laser!!! If you don't, a small but constant drain on the battery will occur, opening up the possibility that you will have a dead battery when you go to use the laser next.



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To change/charge the battery in your RPL-Blue-20 laser, unscrew and remove the tailcap, throw it in the toliet, yank that silver handle on the cistern down, and flush it away...O WAIT!!! YOU'LL NEED THAT!!! So just set it aside instead.
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Tip the used cell out of the barrel and into your hand, and recharge it.

Insert a newly-charged 18650 rechargable Li:ION cell 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.
Aren't you glad you didn't flush away that tailcap now?
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Current usage in lasing mode was measured at 1,709mA (1.079 amps) on my DMM's 4A scale).

To charge the 18650 cell, place it in the charging cradle, orienting it so its button-end (+) positive is on the same end of the chamber in the charger that has a (+) embossed in its bottom.

Plug the small plug on the end of the wall-wart's cord into the receptacle for it on one end of the charger. Plug the wall-wart itself into any standard (in the United States) two- or three-slot 110 volts to 130 volts AC 60Hz receptacle.

A red light on the charging cradle should now come on; this indicates charging is in progress. When the 18650 cell has reached full charge, the light on the charging cradle will turn from red to green.

At this point, unplug the wall-wart, remove the charged cell from the charging cradle, and install it in the laser as directed above.


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This is a laser, not a flashlight. So I won't whack it against a steel rod or against the concrete floor of an outdoor patio, run over it with a 450lb electric wheelchair, try to drown it in the toliet bowl or the cistern, throw it, let my housemate's kitties go #1 on it, stomp on it, or subject it to other abuses that a flashlight might have to endure.
Because this is a DPSS laser, dropping it even onto soft dirt or carpeting will very likely (not certainly, but *PROBABLY*) kill it.
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Blue 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 473nm blue DPSS laser, there's a BIG infrared laser diode that generates laser light at 808nm, this is fired into a crystal called Nd:YVO4 (containing neodymium yttrium vanadium oxide) that lases at 946nm; this laser radiation is finally fired into a crystal called LBO (containing lanthanum boron oxide) that doubles the frequency to 473nm - the bright blue 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 IR (infrared) radiation from the pump diode & Nd:YVO4 crystal.
You don't want that stuff in your blue beam, trust me.
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This is why blue diode lasers are so much more expensive than red ones. Lots of itty bitty parts, and they all need to be aligned by hand. If the polarisation is "off", one of the crystals needs to be turned. With red diode lasers, you just slap in the diode and slap a lens in front of it.

VERY IMPORTANT!!! This laser is NOT a toy, and you MUST NOT shine it into your eyes, other people's eyes, pets' eyes, for that matter, the eyes of any person or animal you encounter.
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Eye damage can occur faster than the blink reflex can protect them, regardless of what species' eyes you irradiate with this laser. So just don't do it.
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And for heaven sakes (and for Pete sakes and for your sakes too) do not shine this laser at any vehicle, whether ground-based like a car or truck, or air-based like a helicopter, airplane, or jet. And if you shoot it at a person in the dark and he turns out to be a police officer, he may think he's being targeted, pull his gun, and hose you down with it.

This is a CDRH Class IIIb laser device. Treat it with respect, and it'll treat you with respect.

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, bag, or the hard-sided case it comes in) if you need to carry it in rainy or snowy weather.

There is an interlock key, a beam shutter, and an LED beam emission indicator. These functions are the safety features needed by a CDRH Class IIIb laser in the United States, and you really should not attempt to defeat them.

You can unscrew & remove the end cap containing the beam shutter to facilitate cleaning of the lens. However, ***DO NOT*** under any circumstances attempt to remove the laser itself from the housing!!! Doing so will void the warranty, and opens the possibility that you may irradiate yourself with 20mW+ of blue laser radiation at 473nm, and at least several hundred milliwatts of IR laser radiation at 1,064nm & 808nm.

According to the website, the beam divergence (full angle) is < 1.00 mrad (milliradians), the beam diameter where it leaves the laser is 1.0mm -1.4mm, and the beam is TEM00 (Transverse Electromagnetic Mode 00) - that is, the beam is circular with a central hotspot with a soft fall off to extinction. This is a typical laser mode, and is how many lasers (well, most lasers for consumer use anyway) are designed to operate.

A certificate of measured power output can be purchased with this laser if necessary.



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Beam photo at ~12".
Beam is not white like this photograph makes it appear; the camera also
added "streaking" artifacts that do not actually appear in the beam.
Beam also bloomed SIGNIFICANTLY; it is not nearly this large in diameter in reality.

Power output was measured at 25.98mW on a laser power meter specically designed for this purpose.
After ~42 seconds, power output was measured at 33.60mW.


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Beam photo at ~10'.
Beam is not white in the center like this photograph makes it appear.

Those rectangular graphic things near the top are marquees from:

Midway ''Omega Race''
Sega ''Star Trek''
Williams ''Joust''
Venture Line ''Looping''
target="new">Universal ''Mr. Do!'s Castle''
Jaleco ''Exerion''
Gremlin/Sega ''Astro Blaster''
Atari ''Tempest''

upright coin-op arcade video games from the 1980s.

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Comparing the beams from this laser and the Optotronics 532nm Green Laser Pointer.
Smoke was used to allow the beams to be visible.


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Just the IR (808nm) component of this laser.
Measures 2.5489mW.


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Spectrometer plot of this laser.
Ocean Optics USB2000 Spectrometer on loan from WWW.TWO-CUBED.COM.


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And here's a photograph of an Exveemon plush with this laser. Exveemon is blue, and has a weapon called a "Vee Laser".
Veemon, digivolve to...EXVEEMON!!!
{shouting} VEEEEEE LASERRRRRRRRR!!!!!!

The Vee Laser isn't blue, but Exveemon himself is, so I believed it appropriate for this web page.
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TEST NOTES:
Test unit was loaned to me by J.O. of www.optotronics.com and was received on 04-04-07. I won't have it for too long - a week at most.

Product was *VERY LIKELY* made in China. A product's country of origin really does matter to some people, which is why I published it on this web page.

The "wall wart" AC charger has a secondary measuring 5.5 volts DC at 450mA.


UPDATE 00-00-00:



PROS:
Unique, attention-getting color that's radiant and unusual for a handheld laser
Beam is "clean", with no visible speckling or artifacts around it
Power output is as much or more than specified
Unique, attention-getting color...o wait I said that already.
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CONS:
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
 
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nice review - thanks to both you and Jack for letting us get a peek at this!!!!

Is that the beam we can see coming from the right hand side of the Marquee photo, or is it artifact??? Looks like the beam to me. Was it inside with the light on??
 
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stevetexas said:
Is that the beam we can see coming from the right hand side of the Marquee photo, or is it artifact??? Looks like the beam to me. Was it inside with the light on??
I think it's just an artifact. The laser was held to the left of and at the same height as the camera when that photograph was taken.

Illumination in the room was from a shaded inandescent light bulb (probably a 100 watt soft white); the light source was not directly exposed to the target wall.
 
nice rewiew:goodjob: how visible is the bean compared to a green laser?
 
I don't have a green laser of comparable power output (20-25mW), so I really can't compare them, sorry. :(
The only green laser that has even close to the power output I'd want is currently nonfunctional. :shakehead:
 
I was surprised. My 17mW RPL blue was a surprising match to green. The beam at night easily beat out a 5mW greenie, though obviously if you put a green vs blue of equal power, the green would win out. Scotopic vision likely plays into the high brightness of 473nm I've been seeing.

And just for the heck of it, here's a review/post I made about the RPL-blue last year:
http://lasercommunity.com/new-rpl-blue-review-dial-up-warning-lots-of-pics-t9738.html
 
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