On-Chip Manipulation of Single Photons from a Diamond Defect

Operating reconfigurable quantum circuits with single photon sources is a key goal of photonic quantum information science and technology. We use an integrated waveguide device containing directional couplers and a reconfigurable thermal phase controller to manipulate single photons emitted from a chromium related color center in diamond. Observation of both a wavelike interference pattern and particlelike sub-Poissionian autocorrelation functions demonstrates coherent manipulation of single photons emitted from the chromium related center and verifies wave particle duality.

Figure 1

The silica on silicon waveguide circuit. (a) Silica on silicon waveguide circuit. Directional couplers $D{C}_1$ and $D{C}_2$ have $\mathrm{\text{reflectivity}}=1/2$ and $D{C}_3$ and $D{C}_4$ have $\mathrm{\text{reflectivity}}=1/3$. A resistive heater at waveguide $d$ allows a relative phase $\varphi$ to be imparted. Photons from an individual chromium related center are coupled into waveguide $a$ from polarization maintaining fiber (PMF) and are sent to APDs via PMF from waveguides $e–f$. (b) Simulated mode of 780 nm light in chip.

Figure 2

Experimental setup and characterization of chromium related centers. (a) Schematic diagram of the optical setup used in this Letter. Photons collected from chromium related centers being excited with a 27 mW 690 nm continuous wave laser are fiber coupled and subsequently sent to one of three measurements—a spectrometer, a Hanbury Brown–Twiss correlation setup or the chip described in the main text. (b) The emission spectrum of a chromium related center used in the waveguide experiments. Inset: Second order auto-correlation function of the chromium related center.

Figure 3

Experimental data acquired from photons coupled to the integrated waveguide circuit. (a) Above: Intensity measured from waveguides $g$ and $h$ as a function of $\varphi$. The upper (black) line is from waveguide $h$ and the lower (blue) line is from waveguide $g$. Below: Second order auto-correlation function of the chromium related center measured from outputs $e$ and $f$. (b) Second order auto-correlation function of the chromium related center measured from outputs $h$ and $f$ when $\varphi =0$.