Narrowband Source of Single Photons for a Quantum Repeater

Sonali Gera a *, Steven Sagona-Stophel a, Mael Flament, Alessia Scriminich, Mehdi Namazi and Eden Figueroa a *

a Stony Brook University, New York, USA

* sonali.gera@stonybrook.edu

Components of a Quantum Repeater Potable Versions

❑ Four Quantum Memories

❑ Two Sources❑ Storage of

Entanglement❑ Measurement

Station

Preparation of pulses to be stored in memories.

Hong-Ou-Mandel Interference of retrieved single photon level pulses

We use Down Conversion in non-linear crystals

P = 𝜀𝜒𝐸. Linear

P = Higher order terms in E Non-linear

E^2 term generates light of frequency different from input frequency

Probability of Down conversion ~ 10-5 Too Low!

Place the crystal inside a cavity!!

Some Enhancement is needed!

Source of Photon Pairs

Cavity narrows bandwidth

To lock cavity lengthSet Up

Master Laser locked to atomic transition (D1 line of Rb)Second Harmonic Generation; for pump productionBow Tie Cavity with Type 1 PPKTP crystal

1

2

3

Pound Drever Hall Lock to maintain cavity length to have down converted photons resonant to the cavityFrequency Lock to have Locking laser 3FSR away from 795nm.

4

5

OPA Output : Down converted photons while the OPA is scanned. Before filtering(right, top) and after filtering(right, middle). Bottom :795nm laser as a reference.

Expected Pair Production Rate :5-6KHz for 5mW of Pump.

Results

Combining the source with the memories Connecting Stony Brook University and BNL on Long Island.

Future Work

Phase matching bandwidth ~ 60GHzFSR = 300MHz