Shanni presented on “Construction of an Entangled Photon Source for Experimenting with Quantum Technologies” at the 2015 Hackaday SuperConference.
Her lecture has been uploaded by Hackaday and is available now available online. CLICK HERE for the link to the HaD Blog and Video.
Prof. Mark Beck from the Dept. of Physics at Whitman College recently published an excellent book titled “Quantum Mechanics: Theory and Experiment.” It is written for an advanced undergraduate/graduate quantum mechanics class. This book presents the theory in its full formalism (with thorough, high-level math), as well as describes five laboratory experiments that explore the use of entangled photons in the undergraduate lab.
Prof. Beck’s laboratory experiments use the same type of system as we describe in Chapter 8 of Exploring Quantum Physics Through Hands-On Projects, so if you are up to the math, we heartily recommend this book to continue your exploration with your entangled-photon system.
Our diy entangled-photon source, shown in the book’s Figure 142, uses two BBO crystals that support type I down-conversion that are mounted according to a design by Paul Kwiat and his colleagues at the Los Alamos National Laboratory.
The nonlinear crystal in our photon entangler comprises two 5 mm x 5 mm x 0.1 mm BBO crystals mounted face-to-face at an angle of 90 degrees to each other. As shown in the book’s Figure 140, pump photons polarized at 45 degrees produce two cones of entangled down-converted photons.
This is the 405 nm pump laser used in the circuit shown in the book’s Figure 141. The laser is built from a Blu Ray disk burner laser diode. We drive the laser diode with 160 mA to produce around 100 mW of 405-nm polarized light. The laser diode is capable of producing 250 mW, but we prefer to drive it much more conservatively. Continue reading
This picture supplements Figure 148 in the book. The colors should help you visualize the paths of the beams in our entangled-photon source: Violet – 405 nm pump laser beam; Pink – 810 nm signal and idler entangled-photon beams. A detailed schematic diagram for the entangler is available in the book’s Figure 147. Figure 149 shows the 405 nm beamstop. Continue reading
quTools of München, Germany is the maker of the quED quantum entangled state demonstrator system to generate and analyze polarization entangled photons. This system is a professionally-manufactured version of the type of entangled-photon generator used by many universities, and similar to the diy version described in Chapter 8 of our book (Figure 148).
quED employs a spontaneous parametric down conversion process (type I or type II; collinear or non-collinear) to generate polarization entangled photon pairs. Fiber-coupled single photon detectors in connection with polarizing filters are used to detect the photon pairs, analyze their polarizations and verify their non-classical correlations. Continue reading
