Review and Impressions of GLP-594

[IsaacT]

REVIEW OF GLP-593.5
Purchased from JCranmer

A few days ago JCranmer put up a FS thread with a GLP-594 laser from CNI.
I immediately told him I was interested, and after a day or two of going back and forth in my head
I decided to pull the trigger.

For those who may not know, I have never owned an exotic wavelength before.
Up until now, I have had 405, 445, 532, 635, and 660. Last week I purchased
a PL520 Diode but have yet to build it. So this is my first! What follows will be a brief
objective review of both the sale and laser itself, followed by my impressions of the laser
and my advice to those thinking about getting a rare, exotic wavelength.

OBJECTIVE REVIEW!!!

1. The Sale w/ JCranmer

PM's: All queries regarding this laser were addressed in a timely manner
and with an appropriate amount of detail. Replies never took more
than a few hours, and his responses never seemed hurried.

Shipping: I sent PP Funds late at night on Friday the 19th, and James shipped
the laser the very next day! You cannot get any better than that. He also PM'd me to let me know
that the item was on its way and updated Paypal with Tracking information. All before I got
home on Saturday!

All in All: 10/10 for JCranmer. I would DEFINITELY purchase from him again!

2. The Laser :drool:

MECHANICS: First of all I want to briefly cover how 593.5nm lasers work,
as it will be important when viewing the rest of this section.

593.5nm Lasers are much like 532nm lasers in that they are DPSS, or Diode Pumped Solid State, Lasers.
532nm Lasers use an 808nm Diode to Pump a Crystal, causing it to lase at 1064nm, the photons from which
are passed through a KTP Crystal which frequency doubles(wavelength halves) the
1064nm laser light into 532nm laser light.
593.5nm lasers use a similar method, but instead of pumping a crystal to produce
only 1064nm laser light, these produce NOT ONLY 1064nm laser light, but also a line at 1342nm.
These two lines pass through non-linear optics and are combined, then doubled to 593.5nm.
(If anybody sees any errors please let me know so I can fix them).

So one interesting thing I have seen when using this laser is that on startup the laser starts
in the green spectrum and then moves up to yellow fairly quickly. Having read about 593.5nm
lasers while waiting for the shipment, my guess is that the 1064nm light is being doubled before
the other line at 1342nm starts lasing. Here is a video of what I see:




DIVERGENCE: The divergence on this laser is pretty average for a DPSS laser(I think?)

Aperture Beam Diameter: 1.5mm
Beam Diameter @ 8 meters: 12mm
Divergence: 1.3 mRad

MODE HOPPING: I have yet to see any mode hopping, but that
doesn't mean that it is not there. I will be keeping a close eye on this laser during use and
report back any mode whoring it engages in. (pardon le french).

The Host: The host is very sturdy and weighs well in the hand.
The material is clearly metal of some sort, and the finish is a glossy black with gold accents.
The button is responsive and clicks when you depress it. From a tactile point of you this is a big plus.
Cheaper lasers tend to have a mushy button, while this one reacts much like a mechanical keyboard.


PICTURES!!!!!

Well, that is all the pictures for now, but here is a video:



MY IMPRESSIONS OF THE LASER

I am very impressed by the warm color of this wavelength. It is really like a liquid, fiery gold light
in real life and I feel that the camera did an excellent job capturing the beauty of this wavelength.
I find the technology used to be very interesting, and I think it will always hold a spot
on my shelf as one of my best lasers. Now that I have a 594nm laser, I really want to look
into getting a 589nm, a 473nm, and a 488nm.....yeah about that job! Lol :thinking:

Suggestions: If you are like me, and have only ever had the common wavelengths
I would highly suggest branching out and filling out your wavelength collection.
There is something beautiful about the technology that goes into these complex lasers that
really sets them above other lasers. Even if you don't make a lot of money you can sometimes
find great deals, just keep your eyes open and you will probably see more deals than you think you will.

CLOSING NOTES:

I hope you all enjoyed my review of the GLP-594 and enjoyed the media included.
If you liked what you saw or if you have any critiques for me, be it media presentation, scientific
fact corrections, or
just general notes, please leave me a comment and I will respond appropriately.

Thanks for looking!!!! :thanks:
-Isaac​

 

[Moistenator]

Love it! What a great review! and a great buy too! Good work OP! +1

 

[eugene420]

Nice review there :beer: Do you know what it's out putting?

That model looks a lot like my Rigel I bought from Laserglow, pretty sure CNI makes it..

Anyways nice purchase, and keep collecting those exotic wavelengths!

 

[mhemling33]

Yeah I am jealous not gonna lie.... did you use fog or is the 593.5nm a fairly bright wavelength? I have never seen one in person and I have been hesitant on them because they are only a couple mw, but when i watch reviews like yours they look so good and the beams are beautiful.

 

[IsaacT]

This one is outputting 1mW to 2mW(my first eye safe laser since 8th grade, go figure lol). 190 dollars was a hard pill to swallow for a few milliwatts.....UNTIL i got it. I am 100% satisfied with this beauty.

I did use fog to get the pictures like they are, however the lights were on in the room I was in(I wanted to be able to have the beautiful host look clean and detailed in the pictures). In complete darkness you can see the beam if you bounce it off a mirror and have it coming back at you at a very shallow angle. This is the trick I use to enjoy all my low powered beams and/or difficult to see wavelengths like 405. In any lighting though, the rich golden color is easy to see and bright.

 

[RA_pierce]

Nice review.
Yellow lasers are way cool.
They are expensive but they are worth every penny. Brightness is almost equal to 532.

@wannaburnstuff
Get 589 next. It's way more stable and available in more power! The $/mW is a little better, too. I've never seen 594 but the color should be pretty similar.

 

[IsaacT]

The cost per milliwatt is better??? Consider my attention grabbed! I think all my exotics I am going to try and get in the same sort of host, that GLP.

Course, that may be a nice idea in theory but impossible in practice. I know 473 usually comes in the blue pointer host.

 

[Trevor]

Fun fact about the 593.5nm generation process!

Short version: It's not doubling, but it is summing.

Long version: Doubling (known as second harmonic generation) is simply a special case of sum frequency generation - a scenario in which two photons are combined to create a single new photon. In a green laser, two photons of the same wavelength (1064nm), and therefore same energy, are combined. Because the resultant photon has precisely twice the energy as its parents, it has has twice the frequency (and half the wavelength). The process for 593.5nm involves combining two photons of differing wavelengths. The resultant photon's frequency, and therefore wavelength, is dependent upon the energies of the photons combined to create it. In your laser, 1064nm and 1342nm photons go in and out comes a 593.5nm photon.

Bonus fact: In the early days of 593.5nm pointers, if the temperature was not right, sometimes the 1342nm wouldn't begin lasing and the pointer would just emit green.

Sorry for the wall of text. I love DPSS. It's so damn cool.

Trevor

 

[Sigurthr]

Nice review, and I told you that you wouldn't be disappointed.

Your laser looks pretty damn stable too. I often wish I went for the Rigel-2 or Rigel-5 instead, as these 593.5nm pointers tend to be a lot more stable at lower wavelengths. Mine will start up around 2mW and then bounce between 5mW and 9mW for a while, then finally rise to 8-10mW for about 15sec, then it will go back to bouncing around before settling back down around 2mW by time the duty cycle is almost up. Every couple of cycles it will peak at 19mW for a few seconds as well. No mode hopping but I'm guessing the 1342nm is the basis for the instability. Though, mine has never shown any green emissions.

 

[IsaacT]

According to some LPM readings this goes between 1-3mW, but JCranmer said he didn't really trust LPM readings at this low of output. And that sounds good to me, so while it may hit 2mW from time to time, or even settle there I am just going to call it 1mW.

Fun fact about the 593.5nm generation process!

Short version: It's not doubling, but it is summing.

Long version: Doubling (known as second harmonic generation) is simply a special case of sum frequency generation - a scenario in which two photons are combined to create a single new photon. In a green laser, two photons of the same wavelength (1064nm), and therefore same energy, are combined. Because the resultant photon has precisely twice the energy as its parents, it has has twice the frequency (and half the wavelength). The process for 593.5nm involves combining two photons of differing wavelengths. The resultant photon's frequency, and therefore wavelength, is dependent upon the energies of the photons combined to create it. In your laser, 1064nm and 1342nm photons go in and out comes a 593.5nm photon.

Bonus fact: In the early days of 593.5nm pointers, if the temperature was not right, sometimes the 1342nm wouldn't begin lasing and the pointer would just emit green.

Sorry for the wall of text. I love DPSS. It's so damn cool.

Trevor

Yeah, I included a bit about how they work in the review but I didn't exactly understand summation very well. I knew two lines went in and one went out. Also, if you check out the first video in my review you can see that "Bonus Fact" in action. When turned on it sometimes lasers green for a split second before the summation you referred to kicks in.

+1 for the very easy to understand explanation of summation! Is there a formula for it? I tried averaging but that doesn't really work because it would be a higher wavelength with averaging....

Thanks,
Isaac

 

[Trevor]

Yeah, I included a bit about how they work in the review but I didn't exactly understand summation very well. I knew two lines went in and one went out. Also, if you check out the first video in my review you can see that "Bonus Fact" in action. When turned on it sometimes lasers green for a split second before the summation you referred to kicks in.

+1 for the very easy to understand explanation of summation! Is there a formula for it? I tried averaging but that doesn't really work because it would be a higher wavelength with averaging....

Thanks,
Isaac

I didn't watch the video and see that... I will now! It's a little inconvenient to have it sometimes be green, but I think it's pretty cool to be honest.

I noticed your explanation and thought I'd elaborate. With all the really nice diode lasers around here, exotic DPSS doesn't get the attention it used to. It's nice to see someone taking an interest!

+1!

Trevor

 

[IsaacT]

I actually really enjoy the fact that it is green sometimes for a second at startup! In my mind I can see how the light is excited in phases. I imagine the crystal heating slightly from lasing and that secondary line at 1342nm coming out just a hair behind the 1064nm line. It is beautiful because it gives you a tangible perspective of the design inside the glossy exterior.

 

[Sigurthr]

The formula for SFG is: 1/(1/lambda1 + 1/lambda2)

1/(1/1064 + 1/1342) = 593.46

 

[IsaacT]

That is brilliant! So after looking at the formula for a bit, it looks like your goal in wavelength summation is to sum the wave numbers first by the formula:

Wavenumber=1/wavelength

And then convert the resulting wavenumber to a wavelength by the same formula such that:

1/(summed wavenumbers)=Wavelength

That is an awesome formula and one that I am going to have to add to my notebook. Thanks!!!

 

[Sigurthr]

Hehe, glad to help.

Btw, "wavenumber" is frequency.

Frequency = 1/lambda
(lambda is the symbol for wavelength)

SFG = Sum Frequency Generation, so, you literally just sum the frequencies.

 

[IsaacT]

Ah okay, yeah I looked it up and wavenumber is spatial frequency. I was remembering the formula:

f=c/lambda which is why it did not initially make the most sense.

Thanks again for the explanation!