arXiv subjects

H. Snijders

Publications and source records attributed to H. Snijders.

4 recordsLinked to original sources

arXiv2025

Silicon nitride based integrated photonic circuit to control a cold-atom source

We have developed a silicon nitride based photonic integrated circuit (PIC) that is responsible for the cooling, pumping and imaging of cold rubidium 87 atoms. The photonic integrated circuit consists of two chips placed next to each other and has a total area of 2x2~cm$^2$. This greatly minimizes the area needed while still having all the optical control functions to create, control and measure a magneto-optical trap (MOT). The piezo electric material Lead Zirconate Titanate (PZT) on the PIC is employed for phase shifting a Mach-Zehnder type configuration where extinction ratios up to 50 dB and switching speeds of 1 MHz are achieved. For the first time a two and three dimensional rubidium 87 MOT is realized using an active PIC. For the three-dimensional MOT, we measure $7\cdot 10^7$ atoms with a temperature of 270~$μ$K.

physics.atom-ph↗

arXiv2025

Miniaturized optical system for a chip based cold atom inertial sensor

We miniaturized the complex optical system responsible for the cooling, pumping and imaging of an on-chip based cold atom inertial sensor. This optical bench uses bonded miniature optics and includes all the necessary optical functions. The bench has a volume of 35x25x5~cm$^3$. We developed a laser frequency lock adapted to the optical bench using saturated absorption in a rubidium cell. The entire laser source based on frequency doubling of 1.56~$μ$m fiber lasers, including the control system and the saturated absorption module, fits in a $5U$-rack. Using the miniaturized bench, we realized two and three dimensional magneto optical traps for Rubidium 87 atoms.

physics.atom-ph↗

arXiv2021

Artificial coherent states of light by multi-photon interference in a single-photon stream

Coherent optical states consist of a quantum superposition of different photon number (Fock) states, but because they do not form an orthogonal basis, no photon number states can be obtained from it by linear optics. Here we demonstrate the reverse, by manipulating a random continuous single-photon stream using quantum interference in an optical Sagnac loop, we create engineered quantum states of light with tunable photon statistics, including approximate weak coherent states. We demonstrate this experimentally using a true single-photon stream produced by a semiconductor quantum dot in an optical microcavity, and show that we can obtain light with $g^{(2)}(0)\rightarrow1$ in agreement with our theory, which can only be explained by quantum interference of at least 3 photons. The produced artificial light states are, however, much more complex than coherent states, containing quantum entanglement of photons, making them a resource for multi-photon entanglement.

quant-ph↗

arXiv2016

Purification of a single photon nonlinearity

We show that the lifetime-reduced fidelity of a semiconductor quantum dot-cavity single photon nonlinearity can be restored by polarization pre- and postselection. This is realized with a polarization degenerate microcavity in the weak coupling regime, where an output polarizer enables quantum interference of the two orthogonally polarized transmission amplitudes. This allows us to transform incident coherent light into a stream of strongly correlated photons with a second-order correlation function of g2(0)~40, larger than previous experimental results even in the strong-coupling regime. This purification technique might also be useful to improve the fidelity of quantum dot based logic gates.

quant-ph↗