Mid-infrared coincidence measurements on twin photons at room temperature

Abstract

Quantum measurements using single-photon detectors are opening interesting new perspectives in diverse fields such as remote sensing, quantum cryptography and quantum computing. A particularly demanding class of applications relies on the simultaneous detection of correlated single photons. In the visible and near infrared wavelength ranges suitable single-photon detectors do exist. However, low detector quantum efficiency or excessive noise has hampered their mid-infrared (MIR) counterpart. Fast and highly efficient single-photon detectors are thus highly sought after for MIR applications. Here we pave the way to quantum measurements in the MIR by the demonstration of a room temperature coincidence measurement with non-degenerate twin photons at about 3.1 μm. The experiment is based on the spectral translation of MIR radiation into the visible region, by means of efficient up-converter modules. The up-converted pairs are then detected with low-noise silicon avalanche photodiodes without the need for cryogenic cooling.

Mid-infrared coincidence measurements based on intracavity frequency conversion

“…It was estimated an incoming power of P = 5.8 ± 0.1pW . As demonstrated in[15] a clear peak of coincidence was observed. The coincidence window was equal to 1…”

“…This process is called multipair emission in SPDC and it is well known to have a detrimental effect on the coincidence measurement [18]. The experimental coincidence measurement was performed with an incident pump power set to an optimal value of 70mW [15]. The conversion efficiency of the SPDC process is estimated to be η = −110dB.…”

“…Figure 5. Collected signal from a single detection unit [15]. and a peak of rate of 105 ± 1cps was measured, after 10s of integration.…”

Perspectives for Applications of Quantum Imaging

“…A number of experimental implementations have also demonstrated this principle and verified that even correlations and entanglement can be preserved . Quantum frequency conversion, which is driven primarily by that task of bridging wavelengths for transmission over distance and storage in quantum memories will play a crucial role in future quantum communication networks.…”

GHz-bandwidth upconversion detector using a unidirectional ring cavity to reduce multilongitudinal mode pump effects

“…However, our proposed GHz-upconverter can easily be extended to the mid-IR region (2 -5 μm) by implementing minor changes to the PPLN period (i.e. change to Λ > 20 μm) and the surface coatings of the ring cavity optical components [14,16]. Such mid-IR GHz-upconverter may serve as a better alternative to liquid-N 2 cooled HgCdTe photodetectors, not only for the elimination of cumbersome cooling requirements but also for significant enhancements in SNR.…”