Semiconductor-Based Detectors

Narrowband Single Photons for Light-Matter Interfaces

“…In this regime, the experiment can probabilistically produce and detect single photon pairs at any given time, further referred to as 100% duty cycle. Unfortunately, this important feature is almost never addressed in the literature for duty cycles below maximum, with only two references reporting on their actual values [31,48] significantly below 100%. We can only infer shortcomings from statements on the resonance condition, as an OPO that is not resonant with the pump frequency always requires a locking cycle, a period during which no photons can be detected due to stabilisation at the single photon frequency.…”

“…However, multi-photon suppression and indistinguishability experiments have yet to be published. [48] 0.11 n/a n/a MCC Chuu [82] 1410 n/a n/a Bao [44] 6 n/a 97 Etalons Yang [70] Tian [71] n/a 95 Filtering line Wang [45] n/a n/a MCC, Type I Kuklewicz [42] 0.07 n/a n/a Not locked Haase [77] 1.0 n/a n/a Filtering line Ou [28,41] n/a n/a Type I Luo [50] -0.020 n/a Not locked, waveguide Ahlrichs [52] 33.7 n/a 96 Filtering line Monteiro [49] n/a n/a Type 0 [59] Benabid, F., Couny, F., Knight, J., Birks, T. & Russell, P. Compact, stable and efficient all-fibre gas cells using hollow-core photonic crystal fibres. Nature 434, 488-491 (2005).…”

“…This has the benefit of easy and deterministic separation of the pair on a polarisation beam splitter behind the cavity, however, achieving double or triple resonance is challenging due to the birefringence introduced by the crystal. In order to overcome this issue, different solutions have been realised: compensation crystals [29,42,48,78], the clustering effect [31,44,50,52,71,79,82] or in our case, a novel technique utilising a half-wave plate [32]. Compensation crystals are a straight forward approach that cancels out the introduced birefringence through an additional crystal with its optical axis rotated by 90 ○ .…”

“…The two main approaches are bi-directional standing-wave cavities (SW) [29,42,44,48,49,52,70,71,82], where the nonlinear crystal is traversed twice per round-trip, and travelling-wave resonators (TW) [31,32,43,[77][78][79], most importantly bow-tie cavities, single directional with only one pass of the light through the crystal per round-trip. TW cavities offer some advantages like lower losses per round-trip, increasing the finesse, or easy spatial distinction between incoming and outgoing beams, beneficial for detection of error signals and lowering the observed rate of unwanted photons created by back reflections of the pump light.…”

“…In recent years, most efforts to advance the field came out of China [44,45,48,70,71], Germany [29,50,52,[72][73][74][75] and Spain [31,[76][77][78][79], producing photon sources at various wavelengths resonant with atomic transitions in different memory schemes. During this time, new techniques for birefringence compensation and filtering were developed, resulting in higher spectral brightness, and passing the threshold to make OPO-based photon generation attractive for quantum information processing and quantum communication [1,4,6].…”