ElectroHolography Laboratory

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=====Characterization Machine Documentation=====

====18 Channel Devices====
These devices are becoming well understood and are relatively straight forward. If this is your first testing experience, start here.

==Previous Work==
 The steps to get the device to the testing stage are as follows:

  - Wiki Page Created
  - Polishing
  - Device Pictures Taken
  - Metricon Reading Completed
  - Wire Bonded
  - Impedance Matching Completed

==Prism coupling==

  - Choose the appropriate mounting stage and attach the mounting bracket to the characterization machine.
  - Center the device on the mount and lower the mounting screws to hold the device in place.
  - Choose the correct prism (TE for X cut devices, TM for Y cut devices)
  - Clean both the prism and the sample
  - Dry mount the prism to the sample applying pressure until finger tight. (DO NOT Over Tighten as you will break the sample or prism.)
  - Check for the rainbow reflection under white light of the wet spot.
  - Place the mount in the characterization machine.

==18 Channel Device Parameters==
These are just close approximations you will always need to fine tune.

^                    ^  Red      ^  Green    ^  Blue     ^
|  Laser Voltage     |  5V       |  5.5V     |  6.5V     |
|  Angular Reading   |  354°     |  357°     |    5°     |
|  Center Frequency  |  450 MHz  |  480 MHz  |  550 MHz  |

==Alignment==
Now that you have mounted the device you are ready to align the machine. Using the table in the section before do the following:

  - Connect the RF cable to the Transducer you wish to test.  {{  ::a7_070.jpg?200|  }}
  - Power on the Laser to the appropriate voltage.
  - Check the polarization (adjust for least light transmitted through a horizontal polarizor).
  - With the adjustable aperture all the way open rotate the sample and position it to the correct angular reading.
  - Adjust the XY stage and rotation stage until waveguiding in the desired mode is achieved. It should look like the picture on the right.  
  - Set RF generator to the correct center frequency. (Verify that is is outputting a signal and that the amplifier is on)
  - Move the platform vertically until you see deflected light.
  - Manually scroll through frequencies to verify that the light truly is deflected light. 
  - Close the aperture and fine tune your adjustments.
  - Take a picture of the coupled light in the sample and a short video of the sweep of deflected light.

==Automatic Testing==
Now that you have a working device it is time to collect some data. Do the following:

  - Verify the polarizor  on the power wand is properly oriented.
  - Place the power wand so that it is aligned with the edge of the device and centered vertically.
  - Rotate the linear actuator until the marker reads 90. degrees.
  - Record the "Sample Number", "Transducer", "Mode", "Laser Voltage", " "Wand Offset from Zero", "Distance to Detector",  "Wand Angle Reading", and any notes in the Labview program.
  - Set the test parameters in the correct fields.
  - Close the Black Box.
  - Make sure the "Output to File" button is pushed.
  - Hit Run

Good results look like this: 
{{:samples:a:aom-a1-green-6.10.2015-8.55am-graph.jpeg?300|}}

Once you have finished testing all colors and modes run it through the Matlab code to compare results.

Congratulations! You're done.
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