ElectroHolography Laboratory

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=====New D Wafer (Made by Christopher)=====

==Orientation==
This wafer was not cut therefore the two flat sides provide all orientation clues.

For the purposes of this page the correct orientation is with the large flat side to the right and the small flat side to the bottom left. The transducers in each group increase in frequency as they move down the device. When the gap is reached the transducers return to the original size and then decrease again.

==Testing==

While attempting to test the device I increased the signal strength to 36dBm (about 4W). At that power the wire bond lit up light a incandescent light bulb and broke in two pieces. Knowing that it would not hurt the device I repeated the experiment and got the same results. We will have to change the manner we connect the device if we want input signals of more than 4W.

With the one remaining set of wire-bonds I sent a 30dBm signal at 120MHz into the long transducer and received that same signal on the shorter transducer. It measured -10dBm. I then reversed the setup and sent from the short side and received from the long side. The signal received had a strength of -20dBm suggesting the long transducer creates more powerful SAW waves.

==Additional Testing==
(created by Miles Rennick)

8/24/15
In Response to the wire-bonds breaking at high signal strengths, I replaced where there was a single wirebond with a set of 5 wire-bonds to divide the current, for one of the two bigger sets of transducers. I then impedence matched the channels for the long and short transducers around 100Mhz (INSERT PIC). I used a (38nH?) Inductor for the short transducer channel, and a 10ohm resistor for the long transducer channel. The short transducer channel doesn't really matter as much since we will use the channel to get a reading (output). The 10ohm resistor I later removed since it could not take high voltage. 

Using a process similar to the "d_wafer" device (see [[samples:d_wafer|_device]] ), Scott and I found diffracted light caused by shining a red laser (PUT LASER SPECS HERE) at the mirror on the device from the front while sending a 100Mhz signal. Here are the three power readings we took: 

Signal
On: 2.7uW, 2.6uW, 4.0uW
Off: 6.9uW, 2.8uW, 3.6uW

with this we can find a ratio.The distance from the diffracted light to the reflected beam 254mm away from the device was 6mm. The angle of diffraction was about 1.33 degrees. The lower power that we could see diffraction was -20 to -22dbm from the signal generator.

I was unable to see any sign of diffracted light simply shining through, or reflecting off, the lithium niboate. I was however able to see similar results of diffracted light by shining the laser off the mirror from the back! The angle of diffraction was similar and these are the power readings.

^   Signal Strength   ^      ON  ^     OFF  ^
|  -20dbm   |  1.41uW  |  1.33uW  |
|  -15dbm   |  1.66uW  |  1.29uW  |
|   -10dbm  |  3.25uW  |  1.30uW  |

Here is a link to my google docs folder that contains a video of this. It's titled "aom_device_modes.MOV". [[https://drive.google.com/open?id=0B31K0y2qoVx9fkxOSlQ3cnEzMUJ6SUQ0TUpYVUQwWkVaTjZsVFVxd21ZajV3cm5vRnpjMlk]]

I also did a scan from 10Mhz - 200Mhz using a program Drew created on LabView and was able to see the diffracted light move!Pics and info to follow later.
ElectroHolography Laboratory

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