d2:laser_controller
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d2:laser_controller [2019/03/25 23:21] – Michael Radunsky | d2:laser_controller [2020/05/04 19:03] – Michael Radunsky | ||
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[[http:// | [[http:// | ||
- | =====Description: | + | ===== Description: |
The laser controller has two temperature controllers capable of sub-mK stability(( Sub-mK stability requires a proper thermal design and proper tuning of the temperature controller to the thermal plant. If you did not purchase a D2-100 Diode Laser with your Laser Controller, please read the section on tuning the temperature controller.)) and a 200 mA or 500 mA precision current source based on the Libbrecht-Hall(( Libbrecht and Hall, A Low-Noise, High-Speed Current Controller, Rev. Sci. Inst. 64, pp. 2133-2135 (1993).)) circuit. | The laser controller has two temperature controllers capable of sub-mK stability(( Sub-mK stability requires a proper thermal design and proper tuning of the temperature controller to the thermal plant. If you did not purchase a D2-100 Diode Laser with your Laser Controller, please read the section on tuning the temperature controller.)) and a 200 mA or 500 mA precision current source based on the Libbrecht-Hall(( Libbrecht and Hall, A Low-Noise, High-Speed Current Controller, Rev. Sci. Inst. 64, pp. 2133-2135 (1993).)) circuit. | ||
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- | =====Purchase Includes: | + | ===== Purchase Includes: ===== |
<WRAP group> | <WRAP group> | ||
<WRAP half column> | <WRAP half column> | ||
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**Setpoint In** | **Setpoint In** | ||
- | SETPOINT IN is an analog input. When the SETPOINT ENABLE is LOW (0 V) the SETPOINT IN voltage value sets the injection current instead of the front panel dial. | + | SETPOINT IN is an analog input. When the SETPOINT ENABLE is LOW (0 V) the SETPOINT IN voltage value sets the injection current instead of the front panel dial. |
This input is rolled off at 14 Hz, which is not much higher frequency than the front panel dial, which rolls off at 8 Hz, with a second pole at 4 Hz. Therefore, noise can enter the circuit at this point and this input should be used with caution. | This input is rolled off at 14 Hz, which is not much higher frequency than the front panel dial, which rolls off at 8 Hz, with a second pole at 4 Hz. Therefore, noise can enter the circuit at this point and this input should be used with caution. | ||
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When disconnected, | When disconnected, | ||
- | The Servo Input on the front panel continues to function when the SETPOINT ENABLE is pulled low. | + | The Servo Input on the front panel continues to function when the SETPOINT ENABLE is pulled low. Only the Coarse and Fine Current Adjustments are disabled. |
=====Turning on the Laser Diode===== | =====Turning on the Laser Diode===== | ||
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====User Control of the Poles and Gain==== | ====User Control of the Poles and Gain==== | ||
- | If you remove the right side panel on the Laser Controller, for each stage of temperature control, you will see the panel shown in <imgref side_adjustb> | + | If you remove the right side panel on the Laser Controller, for each stage of temperature control, you will see the panel shown in <imgref side_adjustb> |
Similarly, the switches labeled " | Similarly, the switches labeled " | ||
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- Turn on temperature loop. | - Turn on temperature loop. | ||
- Adjust set-point to approximately desired temperature. | - Adjust set-point to approximately desired temperature. | ||
- | - Turn up the gain. Keep increasing the gain until the temperature error (front panel BNC) just start to oscillate or ring with very little damping. If oscillation too large, reduce gain. Measure the period of oscillation. | + | - Turn up the gain. Keep increasing the gain until the temperature error (front panel BNC) just starts |
- Turn off the Laser Controller. Measure resistance between " | - Turn off the Laser Controller. Measure resistance between " | ||
- Take the measured oscillation period in step 6 and divide by two. Set the Integrator time constant to this value. For instance, if you measured a period of oscillation of 14 seconds, turn on the 4< | - Take the measured oscillation period in step 6 and divide by two. Set the Integrator time constant to this value. For instance, if you measured a period of oscillation of 14 seconds, turn on the 4< |
d2/laser_controller.txt · Last modified: 2024/03/27 15:33 by Thomas Bersano