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干涉仪实验

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Michelson interferometer

Sliver mirror

Sliver mirror Sliver mirror with piezo

Sliver mirror

HeNe source

Equipment

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Equipment list

1. He-Ne laser source

2. Silver mirror

3. Pizzo and controller with power source

4. Beam splitter

5. Detectors

6. Oscilloscope

7. Analog signal source

8. Other essential equipment in the optical experiment

Step 1

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Set up the HeNe laser source and make sure the beam can incident to the first collimation mirror in a straight line.

Step 2

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Set up the second collimationmirror and then moving the beam to the other line and pass through the Iris

Step 3

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Using 2 Irises to collimate the beam. As shown in the picture, just confirm the beam light can across these two Iris perfectly.

Step 4

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Assembling the beam splitter and first reflect silver mirror according to the picture in this page.

Step 5

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Implement the second reflect mirror with Piezo and make sure all the reflect beam canbe intersected in the beam splitter.

Step 6

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Set up the detector to receive thecoherent beam from the beam Splitter and connect the detectorTo the OSC and power supply.

After that, all the preparations arefinished. Then, connect the analogsignal source to the piezo power supply to start the experiment.

Piezo system tips

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How to build up a piezo system?

1)In order to drive a piezo,it is need a power supply and signal source.

2)And also need a software APT to control the power supply. In this experiment we are using

the software download from ‘Thorlabs’

http://www.thorlabschina.cn/software_pages/viewsoftwarepage.cfm?code=APT

3)Hardware connection can be find below:

Output

Signal Source

Set up the APT

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1) Connect a 0-10V external source to the EXT IN connector on the rear panel.

2) In the GUI panel, click the ‘Settings button to display the settings panel.

3) In the ‘Drive Input Source (Open Loop)’ field, select Analogue Input (Ext In) +SW.

4) In the ‘Analogue Input Source (Ext In)’ field, select SMA Input.

5) In the ‘Feedback Loop’ field, select ‘Open Loop’.

6) Click ‘OK’ to save the settings and close the window.

Two things need to remind, which are the voltage of signal source should be in the range of 0V~10V, and the frequency needs keep blow 1KHz.

Expected results

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Questions

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1. Measure the lengths of the two arms of the interferometer and calculate the difference.

The typical width of the spectrum of a HeNe laser is 1.5 GHz. Estimate its coherent

length. Would you expect the length difference of the two arms of the interferometer

has a significant effect on the interference visibility? Explain why.

2. Discuss other effects that may reduce the interference visibility in your setup.

Reference: Lecture notes on Coherent Optics (Advanced Optics I, week 18)