Narrow-band SHG for pumping SPDC
We just succeeded in locking a cavity to enhance the nonlinear second-harmonic generation (SHG) process in a periodically poled lithium niobate crystal. In this process, narrow-band 1310nm light is frequency doubled to 655nm light. This light will then pump a setup for generating narrow-band polarization-entangled photons via cavity-enhanced spontaneous parametric downconversion (SPDC).
![](https://quantum.fmf.uni-lj.si/wp-content/uploads/2022/02/SHG_cavity-1.jpg)
![](https://quantum.fmf.uni-lj.si/wp-content/uploads/2022/05/entanglement_distribution_satellite_v2.png)
![](https://quantum.fmf.uni-lj.si/wp-content/uploads/2022/02/MAQRO_cavity_plus_aluminum_tube_01_2022_rotated.jpeg)