- #1

Quant

- 18

- 0

- TL;DR Summary
- Advice on production of twin photons

I would be very thankful if somebody helps me with some practical advices about producing twin photons?

I know that twins are produced after a laser ray is directed on a BBO crystal. After the BBO there are two rings of photons and the twins are in the intersection of the rings.

1. I wonder in order to get the two rings must I have the laser ray falling strictly at 90 degree to the BBO? My crystal is very small 3x3 mm so I intend to focus the laser on it which means I would have different angles of them on the BBO so I fear I would not get the rings but a smeared spot. Is this right and what to do? I would like the beam to fall on a point but to be perpendicular. Is there a way to do this?

2. I am not at all sure how to capture the light from the intersection of the rings where the entangled twins are. I will filter the incident beam 405 nm by a filter at 405 but how to collect only the intersection spots to proceed and to direct them to a beam splitter b.e.? To make a mask with two openings? Or fibers?

Thanks in advance.

I know that twins are produced after a laser ray is directed on a BBO crystal. After the BBO there are two rings of photons and the twins are in the intersection of the rings.

1. I wonder in order to get the two rings must I have the laser ray falling strictly at 90 degree to the BBO? My crystal is very small 3x3 mm so I intend to focus the laser on it which means I would have different angles of them on the BBO so I fear I would not get the rings but a smeared spot. Is this right and what to do? I would like the beam to fall on a point but to be perpendicular. Is there a way to do this?

2. I am not at all sure how to capture the light from the intersection of the rings where the entangled twins are. I will filter the incident beam 405 nm by a filter at 405 but how to collect only the intersection spots to proceed and to direct them to a beam splitter b.e.? To make a mask with two openings? Or fibers?

Thanks in advance.