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—groups:mg:experiment:laser:383nmlaser [2022/04/01 09:07] (current) – fim
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 +====== 383 nm Laser system (T-MOT) ======
 +
 +The 383 nm laser system consists of 767 nm lasers which are then frequency doubled to achieve 383 nm light.
 +
 +**External Cavity Diode Laser (ECDL)**
 +
 +For 767 nm lasers, ECDL in Littrow configuration is used. Typically we used the laser diodes from Eagleyard Photonics: EYP-RWE-0790-02000-1500-SOT02-0000
 +
 +Recently, Eagleyard has replaced these with new laser diodes: EYP-RWE-0760-02010-1500-SOT12-0000
 +
 +**TA**
 +  * Output Power: 1.5 W
 +  * Input Current: 2 A
 +  * Injection Power: 32 mW
 +  * Power behind 30dB Isolator: 1.05 W
 +  * Originally this TA was used: EYP-TPA-0765-01500-3006-CMT03-0000. Is this still true?
 +
 +**Fiber**
 +  * PMC-780-5,0-NA012-3-APC-200-P
 +  * Incoupling: 67%
 +  * Power behind fiber: 700 mW
 +
 +===== Frequenzy doubling =====
 +
 +**LBO-Crystal**
 +  * Lenght: 15 mm
 +  * AR coating
 +
 +**Resonator**
 +  * Ring resonator (double Z configuration)
 +  * Length: 280mm
 +  * Curvature of mirrors: 50 mm (S3 and S4)
 +  * Distance of mirrors: 64 mm 
 +  * Waist: 30µm (crystal), 130µm (long arm)
 +  * Transmission: TS3 = 0.049%, T1 = 1.2 %
 +  * Conversion efficiency ENL = 6.1*10^(-5)/W
 +$$E_{NL} = \kappa L_c k_1 h_m (B,\xi) $$
 +  * Linear losses: eL = 0.85(0.15) %
 +  * Finesse: F = 270
 +
 +{{ :groups:mg:experiment:laser:ueberhoeungsresonator_mg.png?400 |}}
 +
 +===== Stabilisation =====
 +  * PDH-Method
 +  * Error signal at about 20 MHz
 +
 +
 +{{ :groups:mg:experiment:laser:mg_aufbau.png?400 |}}
 +
 +===== Stabilisation: Laser 4 - Potassium =====
 +{{ :groups:mg:experiment:laser:image_2022-04-01_110522.png?400|}}
 +Dopplerfree Saturation Spectroscopy on D1 line of Potassium:
 +
 +  * 1st the two beams with similar intensity are generated by the beam sampler and are send trough the glas cell
 +  * one part of the initial beam is going trough the sampler to a double pass aom and then in the other direction trough the glas cell, crossing only one beam. Important: the beam coming from the aom must have a much higher intensity!
 +  * the first two beams, coming from the sampler trough the cell are than monitored by the PD. The signal is substracted
 +  * in or case e use the aom to create the peak on one side of the mainpeak. This is important for the lock-in scheme
 +
 +{{ :groups:mg:experiment:laser:dopplerfreespectrosc.gif?700|}}
 +
 +