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groups:mg:experiment:laser:285nmlaser [2015/10/01 14:40] – [285 nm-SHG] ssauergroups:mg:experiment:laser:285nmlaser [2022/04/06 05:51] (current) – [Locking to Iodine-Spectroscopy] wfriesen
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 ====== 285 nm-Laser (S-MOT) ====== ====== 285 nm-Laser (S-MOT) ======
 The 285 nm Laser consists of a two-stage frequency doubled, raman-fiber-amplifier MOPA. The raman-fiber-amplifier is seeded by a diode laser. The 285 nm Laser consists of a two-stage frequency doubled, raman-fiber-amplifier MOPA. The raman-fiber-amplifier is seeded by a diode laser.
-  * Laser-Diode current: .. mA+  * Laser-Diode current: 280 mA   @which settings?
   * Seed power (is displayed in the //FLPM RMU CCT 1.1.0.0// program): ~ 20 mW   * Seed power (is displayed in the //FLPM RMU CCT 1.1.0.0// program): ~ 20 mW
-<note important>Change values</note> 
  
 ===== Turning on the Laser ===== ===== Turning on the Laser =====
- * Enable main-switch. Set key to standby.+ * Enable main-switch. Now set the key to standby.
  * Wait for the LED to change the color from orange to green to orange (~15 seconds after turning on). Turn the key now.  * Wait for the LED to change the color from orange to green to orange (~15 seconds after turning on). Turn the key now.
  * Start the program //FLPM RMU CCT 1.1.0.0// and select the checkbox of //Laser Enable//.  * Start the program //FLPM RMU CCT 1.1.0.0// and select the checkbox of //Laser Enable//.
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  * //2 - 2.500 W// for //100-150 mW// directly after 285 nm SHG.  * //2 - 2.500 W// for //100-150 mW// directly after 285 nm SHG.
  * Do not exceed much more than //3.5 W//  * Do not exceed much more than //3.5 W//
 + * Flush the SHG with oxygen, by opening the bypass for roughly 10 seconds.
 + * Scan the SHG and optimize the incoupling and crystal position
 + * Lock the SHG, the voltmeter should display a value around 115 mV (@ 2 W Power Setpoint)
 + * Activate the powerstabilization
 +===== Turning off the Laser =====
 + * Unlock the laser in DigiLock
 + * Now just turn off the main-power on the laser
 + * Disable oxygen to 285nm SHG.
  
 ===== Locking to Iodine-Spectroscopy ===== ===== Locking to Iodine-Spectroscopy =====
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             * Move the crosshair to the second slope, rightclick on press //PID: Lock to Slop//.             * Move the crosshair to the second slope, rightclick on press //PID: Lock to Slop//.
  
-==== Lock-Paramters ==== 
-<note important>Add parameters</note> 
  
 +        * **Troubleshooting** 
 +            * If signal in DigiLock-Software does not update/ signal is frozen  -> click the sampling checkbar to activate
 +            * If signal in DigiLock-Software does not show the usual error-signal at correct frequency, but is saturated at left and right edge of the frame (see picture) -> Check the ref input for the lock-in-amplifier (near the iodine spectroscopy). Probably the input signal is too low. It should be slightly higher than 2 V (~2.2V works fine).{{ :groups:mg:experiment:laser:img-20210119-wa0001.jpg?400|}}
 ===== Lasersystem - Typical power values ===== ===== Lasersystem - Typical power values =====
-<note important>Kürzen und nur das wichtigste angeben</note> 
- 
 The 285nm SHG was build by Jan Friebe and is described in his diplomathesis. The 285nm SHG was build by Jan Friebe and is described in his diplomathesis.
  
 === 570 nm-Laser === === 570 nm-Laser ===
  
- * Outputpower after cube to 285 nm-SHG: ~ 1.2 W @ 2.5 W+ * Outputpower after cube to 285 nm-SHG: ~ 1.2 W @ 2.5 W 1140nm pump
  * Operationpower: < @ 3 W  * Operationpower: < @ 3 W
  * Max outpupower: ??? W @ ??? W  * Max outpupower: ??? W @ ??? W
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 === Iodine spectroscopy === === Iodine spectroscopy ===
  
- * Infront fiber: ~ 38 mW @ 0.500 W +== 500 mW pump of the yellow laser == 
 + * Infront fiber: ~ 38 mW
  * After fiber: ~ 29 mW @ 0.500 W (= 400 mV @ 0.500 W) [efficiency ~ 70 %]  * After fiber: ~ 29 mW @ 0.500 W (= 400 mV @ 0.500 W) [efficiency ~ 70 %]
  
- * Infront fiber: ~ 220 mW @ 2.500 W  +== Normal operation (2-3 W) == 
- * After fiber:  ~ 160 mW @ 2.500 W (= 2 V @ 2.500 W) [efficiency ~ 70 %]+ * After fiber: ~ 100 mW 
 + * At iodine cell: 20-40 mW
  
 ==== 285 nm-SHG ==== ==== 285 nm-SHG ====
- + * Outputpower: ~ **100+ mW** @ 2.000 W 
- * Outputpower: ~ 100 mW @ 2.000 W + * Stabilized power (infront AOM): **80-90 mW** 
- * Outputpower: ~ ... mW @ 2.500 W + * Power behind the AOM: **43** mW @ 2.000 W (efficiency ~ 50 %)
- * Stabilized power (infront AOM): **80 mW** +
- * Power behind the AOM: 43 mW @ 2.000 W (efficiency ~ 50 %)+
  
  * Power for the Zeaman-slower: **10 mW**   * Power for the Zeaman-slower: **10 mW**