Developing a self-calibrating system for volume measurement of spheroidal particles using two acoustically levitated droplets.

Acoustically levitated droplets in the nanoliter to microliter range are studied in various fields. The volume measurements of these are conventionally done using image analysis. A precision-produced calibration sphere is often used to calibrate the recording equipment, which is time-consuming and expensive.

Experimental assessment of the effective-medium approach for disordered monolayers of particles with high scattering losses.

The validity of using an effective-medium approach (EMA) to model the reflectivity of a disordered monolayer of particles that scatter light significantly is tested experimentally. To achieve this, we measured the optical reflectivity versus the angle of incidence in an internal reflection configuration of a disordered monolayer of polymeric particles with negligible optical absorption and a diameter of about half a wavelength (size parameter of 1.2) deposited on a glass-air interface.

Compact laser modulation system for a transportable atomic gravimeter.

Nowadays, atom-based quantum sensors are leaving the laboratory towards field applications requiring compact and robust laser systems. Here we describe the realization of a compact laser system for atomic gravimetry. Starting with a single diode laser operating at 780 nm and adding only one fiber electro-optical modulator, one acousto-optical modulator and one laser amplifier we produce laser beams at all the frequencies required for a Rb-87 atomic gravimeter.

Fano Combs in the Directional Mie Scattering of a Water Droplet.

When light scatters off a sphere, it produces a rich Mie spectrum full of overlapping resonances. Single resonances can be explained with a quantum analogy and result in Fano profiles. However, the full spectrum is so complex that recognizable patterns have not been found, and is only understood by comparing to numerical simulations.

Visualizing the electron's quantization with a ruler.

More than 100 years ago, Robert Millikan demonstrated the quantization of the electron using charged, falling droplets, but the statistical analysis on many falling droplets did not allow a direct visualization of the quantization of charge. Instead of letting the droplets fall, we have used optical levitation to create a single droplet version of Millikan's experiment where the effects of a single electron removal can be observed by the naked eye and measured with a ruler. As we added charges to the levitated droplet, we observed that its equilibrium position jumped vertically in quantized steps.