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PCAOM , Polychromatic Acoustic-Optical Modulator

chloderic

Active member
Joined
Jan 21, 2018
Messages
319
Points
43
Hi,

today i played a little bit with my polychromatic acousto-optic modulator and opened the crystal housing.
Bevore closing it i made some pictures and thought, somebody could be interested in this. ...
I guess such a device is known, therefor i must not describe the basic functions.

In my case it is a device from AA OPTO-ELECTRONIC , french.

It is a little bit better one AOTFnC-VIS-TN45-001-RTN01

Features : Multiline operation, high colinearity in 1st order, 405 nm operation, high separation angle between orders 0-1,
high power stability / pointing stability.

The TEC-temperature-stabilized input is an SMC-connector.

63509

The crystal material is TeO2 with an velocity of 675 m/s, it can handle up to 8 lines (independently or simultaneously).
The optical wavelength range is 450-700 nm with an optical transmission > 95% with an active aperture 3 x 3 mm².

63510

The used drive frequency 80-153 MHz is connected to the device with an SMA to control with rise/fall time 1 μs/mm.
This RF-signal is transmitted to the crystal with also golden connections.

63511

63512

Unter the line this device has a diffraction efficiency > 90 %, separation angle ≥ 4.6°, chromatic colinearity ≤ 0.2 mrad , max optical power density 5 W/mm² @633nm (wavelength dependent) and a spectral resolution (FWHM) < 1.5 nm, that means ... a better one ....

The temperature stabilization (type TN ,SMC connector) is under the optical assembly.

63513

maybe we could discuss again a little bit about such devices ?

Greetings

Bernd
 



chloderic

Active member
Joined
Jan 21, 2018
Messages
319
Points
43
Can you be more specific?
I would like to use this device in a project to hide or select individual wavelengths from a signal.
This works with this part without mechanical adjustments and can be adjusted both in the wavelength,
intensity and combination of both with a RF signal.

When assembling the parts, I found by looking in the input that there was apparently dirt burned.
The hardness of Tellurite is 2 on Mohs scale, that's very soft and as well the AR is a solftcoating,
So I opened the part to see how much pollution it really is.

63553

I do not dare try cleaning at the moment.

So in the next step i will look at the RF signal generator from the inside (out of interest),
solder the various cables and try using the RS232 interface to see if there are any restrictions on the contamination.
 

Arctos

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Joined
Mar 6, 2019
Messages
20
Points
3
Has it been repaired before? Solder is 'interesting' to say the least.

Always wanted to see someone make a scanner from these. Heard it's possible but the angle is low so you need super high BQ to do much and at high distance.
 

chloderic

Active member
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Jan 21, 2018
Messages
319
Points
43
Has it been repaired before? Solder is 'interesting' to say the least.

Always wanted to see someone make a scanner from these. Heard it's possible but the angle is low so you need super high BQ to do much and at high distance.
Hi Arctos,

you have seen, that der device ist defective, i am impressed .... so it is.

I do not think that someone will be able to repair it by soldering,
but the seller told me to send an other device, but until now i did not get it.
I am still waiting for the other device and than it will go on with the project.
AND yes... such a scanner will be very interesting , I think you mean somithing like a spectrometer without moving parts ?

Greetings

Bernd
 

diachi

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Joined
Feb 22, 2008
Messages
9,735
Points
113
Yeah, that soldering job in there is a little how ya doin'...

Looks like they used lead-free solder without actually knowing how to solder without lead-free solder. Although, the cheap 60/40 solder I bought from China usually turns out like that too.
 

chloderic

Active member
Joined
Jan 21, 2018
Messages
319
Points
43
At work we are soldering wires at the electrodes of x-ray tubes, may this work for this here? Has anyone of you done something like this himselve?
 

LSRFAQ

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Joined
May 8, 2009
Messages
1,075
Points
83
OK to gently clean the coated faces only, with a swab or tissue using high purity, dry, alcohol. If there is grease, one quick pass with a minimal amount of acetone. Again, high purity chemicals only.

NO water, No ammonia based lens cleaners. One pass per face and call it a day... I hate cleaning my PCAOMs, which is why they now have AR coated glass glued to the housing.

Take a classic tungsten light bulb, put it in a desk lamp, hook up the driver and get about 5 meters away. Turn on a channel, say 514.5 if it is a laser show PCAOM, apply 5 volts to trigger it, and tilt the crystal in your hand while looking thru it. You should see a monochromatic image of the bulb in green at 2 or 3 locations and a few ghost images plus the exit beam of un deflected light.. That is the easy test.

Steve
 

chloderic

Active member
Joined
Jan 21, 2018
Messages
319
Points
43
OK to gently clean the coated faces only, with a swab or tissue using high purity, dry, alcohol. If there is grease, one quick pass with a minimal amount of acetone. Again, high purity chemicals only.

NO water, No ammonia based lens cleaners. One pass per face and call it a day... I hate cleaning my PCAOMs, which is why they now have AR coated glass glued to the housing.

Take a classic tungsten light bulb, put it in a desk lamp, hook up the driver and get about 5 meters away. Turn on a channel, say 514.5 if it is a laser show PCAOM, apply 5 volts to trigger it, and tilt the crystal in your hand while looking thru it. You should see a monochromatic image of the bulb in green at 2 or 3 locations and a few ghost images plus the exit beam of un deflected light.. That is the easy test.

Steve
Hi Steve,

thanks a lot for your tips, they are helpful. Today i got an other crystal from the seller as replacement for the defectiv one.
Now i have 3 of them, all the same but one defectice and all of them are ditrty. At the weekend i will test them and also the 2 HF-devices i have now, one older with 3 channels (the red one from AA, i think you know them) and a newer MDS fom AA with 8 channels and USB.
I have no remote, so i have to use the rs232 in the first case and usb for the second device to configure the frequences of the channels.

Greetings

Bernd
 

LSRFAQ

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Messages
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DO you have the serial protocol for the AA or software? I have a friend who needs that.. He has 3 AA that he needs to adjust...

Steve
 

chloderic

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Jan 21, 2018
Messages
319
Points
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DO you have the serial protocol for the AA or software? I have a friend who needs that.. He has 3 AA that he needs to adjust...

Steve
Hi Steve,

sorry for my late answer .... but, YES i have, see the attached file.
I have also the software for this ....

Greetings
Bernd
 

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