We use BBO crystals as a nonlinear medium to produce type-II spontaneous parametric down-conversion (type-II-SPDC) in the well-known geometry of two ring systems.

[4 mm] Standard length:

• The system already includes a BBO crystal with the standard length of 4mm.

[X mm] Custom length:

• For a potential pulsed excitation (multiphoton generation with femtosecond or picosecond pulses) or a broader target bandwidth of the entangled photons, a shorter length of the nonlinear crystal may be more optimal.
• A deviant crystal length would influence the optimal focusing. Subsequently a change of the whole system in respect to optical and mechanical values must be performed.

Back to Corresponding Options