d2:spectroscopy_module
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+ | ======Spectroscopy Module (Obsolete) ====== | ||
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+ | Model No. D2-110 | ||
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+ | Document Revision: 1 | ||
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+ | Document Last Updated on ~~LASTMOD~~ | ||
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+ | Please read [[: | ||
+ | |||
+ | =====Description===== | ||
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+ | // | ||
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+ | The spectroscopy module provides saturated absorption spectroscopy to atomic rubidium. It contains a rubidium absorption cell, TEC, balanced photodetector, | ||
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+ | // | ||
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+ | <WRAP center round box 520px> | ||
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+ | ===== Absolute Maximum Ratings ===== | ||
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+ | Note: All modules designed to be operated in laboratory environment | ||
+ | <WRAP center round box 60%> | ||
+ | | **Parameter** | **Rating** | | ||
+ | |Environmental Temperature | >15°C and <30°C| | ||
+ | |Environmental Humidity | <60% | | ||
+ | |Environmental Dew Points | <15°C | | ||
+ | </ | ||
+ | |||
+ | |||
+ | =====Specifications===== | ||
+ | <WRAP center round box 500px> | ||
+ | ^ ^ Value ^ Units ^ | ||
+ | ^**Photodiode Amplifier** | ||
+ | | < | ||
+ | | < | ||
+ | | < | ||
+ | ^Set Temperature | ||
+ | ^Temperature Stability| | ||
+ | ^Beam Height| | ||
+ | ^Total package Size \\ (L x W x H)| 4.25 x 4 x 2 | inches | ||
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+ | </ | ||
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+ | =====Inputs, | ||
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+ | **Input Connector**** (****8-pin circular)** | ||
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+ | Power and temperature control signals from the Laser Servo are made through an 8-pin circular connector. | ||
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+ | <WRAP center round box 300px> | ||
+ | ^ Pin ^ Signal | ||
+ | | 1 | TEC+ | | ||
+ | | 2 | TEC- | | ||
+ | | 3 | +15 V | | ||
+ | | 4 | Rth_Rtn | ||
+ | | 5 | Rth | | ||
+ | | 6 | -15 | | ||
+ | | 7 | NC | | ||
+ | | 8 | GND | | ||
+ | </ | ||
+ | |||
+ | |||
+ | **Signal Output (SMA)** | ||
+ | |||
+ | To minimize electro-magnetic interference, | ||
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+ | **Course vertical and horizontal beam positioning** | ||
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+ | The spectroscopy module contains a 3x Galilean beam expander. | ||
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+ | **Fine vertical and horizontal beam positioning** | ||
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+ | The spectroscopy module contains a focusing lens for the signal photodiode on a spring-loaded mount with 2-56 screws for fine adjustment of the beam onto the photodiode (<imgref sas_inside> | ||
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+ | =====Aligning the Spectroscopy Module===== | ||
+ | |||
+ | The spectroscopy module is shipped factory aligned and should need only minor adjustment. | ||
+ | |||
+ | -Fashion two small 1 cm x 3 cm cards from an index card for use as viewing screens. | ||
+ | -Remove the cover on the Spectroscopy Module. | ||
+ | -Following the instructions in section | ||
+ | -At this point the beam should be going through the center of the input and output apertures on the module, the center of the 6 mm lens, and the second pick off should be impinging on the reference photodiode (see <imgref sas_inside> | ||
+ | -Use the card to ascertain the position of the returned beam on the first corner mirror. | ||
+ | -Use the course positioning controls to place the retro-reflected beam as close as possible to the incoming beam. | ||
+ | -Use the card to probe the opposite corner mirror (along short side) to see if the retro beam is now passing back through the input beamsplitter. {{ : | ||
+ | -If the beam is visible on the card, center it with the course positioning controls. | ||
+ | -Check to see that the beam is relatively well centered on the retro reflecting mirror at the end of the Rb cell. If not, the beam is not centered well enough on the 6 mm divergent lens. Start again from Step 3. | ||
+ | -Fold the second card lengthwise (light goes through a single layer) and block the reference photodiode while monitoring the SMA OUTPUT on an oscilloscope or voltmeter. | ||
+ | -Use the Course and fine steering controls to maximize the signal (actual signal is negative) on the voltmeter. | ||
+ | -Remove the card from the reference photodiode. | ||
+ | -Adjust the trimpot until a desired lockpoint for sidelocking crosses zero volts (with oscilloscope connected to the ERROR INPUT monitor, or until an eyeball average of the hyperfine transitions lies near zero volts. | ||
+ | -The spectroscopy module is now ready for use. Replace the cover. |