Who 'd like test our dichoric

[Junktronix]

My package also arrived today. I've got a busy weekend planned so I may not have a chance to test the dichros until Monday or Tuesday. The 5.7W Brightlight projector is supposed to ship on Monday so I will have real-world results after it arrives in a couple of weeks.

[kecked]

now we are talking. the p3flexmods are back and we got all diode builds and working high quality dichro......ahhh life is good. now wee just need 100kps scanners that are the size of a quarter usd with drivers that are 99% efficient and need no heatsinks while also being 1" x1"! a man can dream now cant he.

I'd settle for 1W rgb out the front balance whitelight all diode with 0.5mrad and 3mm at the scanners in a box weighing less than 10 lbs with 60kps 10 degree scanners in a box less than 12"x18"x6" with aom like modulation and perfect alignment that never drifts and perfect overlapped and size matched beams for under 5k. But ok I'll settle for good dichro for now.

[dsli_jon]

...The 5.7W Brightlight...so I will have real-world results after it arrives in a couple of weeks.

Heya, I'll be up there on the other side of the Bay, next week (Tues nite > Sun..) and I've got an 8W RGB, there, so.. You'd be welcome to do some tests with that pup, for a bit.. multi-up 640, 532 VCSEL green (fast modulation..) and multi-up x-polarity 445.. should make for a good candidate for 'typical show-projector components / array-configs' data.. ..Plus you'd get to chum around with one of the finest-designed PJs on the market.. (imho..

..Oh - important detail: I've got to take the 8W with me on the 4th, so... 'window of op' will be Tues > Sun... There will be a 4W, in it's-stead, but it will be fairly-well occupado the following week..

..But, I do-hope you / someone will be able to test with 520, specifically.. very-keen to see how these dichros perform with 520.. Also, looking good we might be able to sync on that Y, then, too, so.. Let's chat..

j

[planters]

Daniel,

I would Just like to review what would be good to know. Please look @ S and P reflectivity and transmission curves for white light @ 45 degree AOI, Also, can you rotate them a bit either side of 45 degrees to see what kind of tolerance they have and freedom we have to use them as something other than right angle turning reflectors. I would like to take this up a notch and look @ wavefront. High end dichroics will specify wavefront distortion for R and T because the quality of the substrates and the stresses induced by the coatings can deteriorate the beam quality. Without getting too fancy, could you take two lasers, one transmitted and one reflected and simply look at the far field spot size with and without the dichroic?

I am going to risk making an assumption here, but can't we estimate the damage threshold for a given wavelength by reducing the typical spot size on the dichroic, let's say 10 square millimeters to say 1/2 -1 square millimeters (or less if you can determine this) and slowly dialing up an easily available, say 1 W laser while watching the reflected and or transmitted beam?

[kecked]

OR when you guys are done you can send samples on to planters and let him bet the piss out of them

[danielbriggs]

Eric,
I've have lent my BB polariser out, which is most untimely.
I don't have a true Shack Hartmann sensor, but I'll do my best to rustle something similar(ish) up.
Yes, I was planning to look at the AOI sensitivity.

Does anyone remember the Semrock 640/660nm dichros? They had a massive effect on divergence; so much that you had to compensate for the apparent focal length by decollimating the red modules. It was all down to the residual stress from the several hundred reflective coatings on the substrate.

[Galvonaut]

OR when you guys are done you can send samples on to planters and let him bet the piss out of them

I like this idea. If planters did a video it'd be even cooler! They are all so informative

Keith

[planters]

Thanks Guys.

Daniel,
I don't think you have to go so far as to perform a true wavefront analysis because the only way the beam quality will matter is in the far field spot. How long do you think your polarizer will be out?

[danielbriggs]

I'll see how soon they can return it to me, but I'd say approximately 10 days to be safe.

[danielbriggs]

Hi All,

I have spent some time this afternoon testing all of the dichroic mirrors on the spectrometer that Bridge has kindly sent.


The Setup:

A temperature stabilised Ocean Optics S2000 was used to make all measurements (at 21°C)




The light source used was a Mikropack HL2000, and was allowed to stabilise for several hours before use.




The calibration was rechecked against an ampoule of neon; (excited with around 10kV, 5mA).




Results confirmed the calibration was accurate. I'm unsure of the purity of the Neon I used, but it's clear there are some other elements in the discharge.
(Red are known neon peaks, black is the received spectrum.)




Bridge sent over 6 unlabelled dichroic mirrors, 3 of one kind, 3 of another; I will simply refer to these as "Type A" and "Type B".
All were tested at varying angles of incidence [0°, 30°, 45°, 60°], with care taken to ensure test conditions were the same throughout.





Example "RAW" plots:

Dichro Type A, No. 2, AOI = 45°, Transmission.




Dichro Type B, No. 2, AOI = 45°, Transmission.





The Results:

The tested spectrum range was 400-800nm

Test results were averaged for each tested mirror, and close concordance was found throughout.
Average transmission plots were then created for each AOI, for each mirror.
(For reflectance plots, simply assume an inversion).


Final spectrum results:






The created spreadsheet with all raw data, plots and individual transmission curves can be downloaded here:
http://www.danielbriggs.co.uk/laser/...DichroTest.zip

File naming convention:
"Dichro_x_y_z_T.PNG"
x=Dichro Type, A or B. A = Transmit Blue, Green, Reflect Red. B = Transmit Red, Green, Reflect Blue.
y=Dichro ID under test aka "repeat".
z=AOI [0°, 30°, 45°, 60°].
T=Transmission test.


Both appear to be very high quality and it is clear either dichroic mirror is suitable for the new 515-520nm DI greens at the standard 45° AOI.


I still intend to produce results for a power meter based transmission/reflection test, as well as wavefront distortion results, however they will have to follow later in the week, as I was pressed for time today.

Comments on any of the test procedure / results welcome.

Thanks again to Bridge for making this possible.

Best Regards,
Daniel