Laser written mirror profiles for open-access fiber Fabry-Perot microcavities.

We demonstrate laser-written concave hemispherical structures produced on the endfacets of optical fibers that serve as mirror substrates for tunable open-access microcavities. We achieve finesse values of up to 200, and a mostly constant performance across the entire stability range. This enables cavity operation also close to the stability limit, where a peak quality factor of 1.

Single mode fiber based delivery of OAM light by 3D direct laser writing.

We demonstrate orbital-angular momentum (OAM) light up to a topological charge of l=3 behind a single mode fiber. Femtosecond 3D direct laser writing is used to fabricate spiral phase plates of l=1,2 and 3, composed of 10 discrete steps, on the tip of single mode optical fibers. These structures efficiently convert out-coupled light from the fiber at 785 nm wavelength into optical vortex beams carrying an orbital-angular momentum of lℏper photon.

Single Quantum Dot with Microlens and 3D-Printed Micro-objective as Integrated Bright Single-Photon Source.

Integrated single-photon sources with high photon-extraction efficiency are key building blocks for applications in the field of quantum communications. We report on a bright single-photon source realized by on-chip integration of a deterministic quantum dot microlens with a 3D-printed multilens micro-objective. The device concept benefits from a sophisticated combination of in situ 3D electron-beam lithography to realize the quantum dot microlens and 3D femtosecond direct laser writing for creation of the micro-objective.

3D-printed eagle eye: Compound microlens system for foveated imaging.

We present a highly miniaturized camera, mimicking the natural vision of predators, by 3D-printing different multilens objectives directly onto a complementary metal-oxide semiconductor (CMOS) image sensor. Our system combines four printed doublet lenses with different focal lengths (equivalent to = 31 to 123 mm for a 35-mm film) in a 2 × 2 arrangement to achieve a full field of view of 70° with an increasing angular resolution of up to 2 cycles/deg field of view in the center of the image. The footprint of the optics on the chip is below 300 μm × 300 μm, whereas their height is <200 μm.

Combining in-situ lithography with 3D printed solid immersion lenses for single quantum dot spectroscopy.

In the current study, we report on the deterministic fabrication of solid immersion lenses (SILs) on lithographically pre-selected semiconductor quantum dots (QDs). We demonstrate the combination of state-of-the-art low-temperature in-situ photolithography and femtosecond 3D direct laser writing. Several QDs are pre-selected with a localization accuracy of less than 2 nm with low-temperature lithography and three-dimensional laser writing is then used to deterministically fabricate hemispherical lenses on top of the quantum emitter with a submicrometric precision.

Ultra-compact on-chip LED collimation optics by 3D femtosecond direct laser writing.

By using two-photon lithographic 3D printing, we demonstrate additive manufacturing of a dielectric concentrator directly on a LED chip. With a size of below 200 μm in diameter and length, light output is increased by a factor of 6.2 in collimation direction, while the emission half-angle is reduced by 50%.

Sub-micrometre accurate free-form optics by three-dimensional printing on single-mode fibres.

Micro-optics are widely used in numerous applications, such as beam shaping, collimation, focusing and imaging. We use femtosecond 3D printing to manufacture free-form micro-optical elements. Our method gives sub-micrometre accuracy so that direct manufacturing even on single-mode fibres is possible.

Spatial solitons in optofluidic waveguide arrays with focusing ultrafast Kerr nonlinearity.

We present an optofluidic nonlinear waveguide array that is fabricated by selectively filling several strands of a photonic crystal fiber with the liquid CCl(4), which exhibits a large focusing ultrafast Kerr nonlinearity. We demonstrate a power dependent formation of a spatial soliton in this novel optofluidic device. The large thermo-optical effect of liquids enables us to control the characteristics of the spatial soliton formation in these nonlinear structures.

Tunable ultrafast nonlinear optofluidic coupler.

We present an optofluidic nonlinear coupler fabricated by selective filling of two strands of a photonic crystal fiber with the liquid CCl4 which exhibits a large ultrafast Kerr nonlinearity. We demonstrate power dependent switching in this novel optofluidic device. The large thermo-optical effect of liquids enables us to tune the behavior of the nonlinear coupler by changing the coupling strength with temperature.