arXiv subjects

Piotr Wasylczyk

Publications and source records attributed to Piotr Wasylczyk.

8 recordsLinked to original sources

arXiv2025

Multiplexed back focal plane imaging with on-chip integrated microlens array

On-chip optical architectures that enable angle-resolved spectroscopy are essential for advancing photonic platforms towards low-volume, scalable, and cryo-compatible devices. Here, we introduce spatially resolved momentum-space imaging using arrays of 3D-printed microlenses directly integrated onto semiconductor optical microcavities. Each microlens functions as an independent optical element with a high numerical aperture (approx. 0.95), enabling parallel back focal plane imaging across, in our implementation, 64 distinct locations. This approach eliminates the need for bulky microscope objectives while maintaining broad wavevector access, even under cryogenic conditions. We demonstrate its versatility across various cavity systems, including dielectric planar resonators, GaAs-based polariton microcavities, and CdTe platforms supporting nonequilibrium Bose-Einstein condensation of exciton-polaritons. The microlenses not only enhance collection efficiency but also enable tightly focused excitation, yielding an order of magnitude reduction in condensation thresholds compared with conventional setups. Our results establish 3D-printed microlens arrays as a compact, versatile, integrated platform for next-generation angle-resolved spectroscopy in nanophotonics and quantum materials.

physics.optics↗

arXiv2025

Non-invasive super-resolution imaging through scattering media using highly nonlinear labels

While scattered light conveys most of the information we perceive, scattering may also distort that information before it reaches our detectors. The problem is acute in many applications, such as in high-resolution microscopy of biological tissue, where scattering degrades both resolution and signal-to-noise ratio. Here, for the first time, we demonstrate that combining two intrinsic properties of scattered light: speckle statistics and the memory effect, with highly non-linear optical response yields, rather surprisingly, super-resolution, low-background, non-invasive imaging of objects completely hidden behind a strongly scattering, opaque layers. Crucially, our technique of Nonlinear Imaging with Speckle Excitation (NISE) does not resort to wavefront shaping, adaptive optics, complicated optical setups, or iterative image reconstruction algorithms. Because the strategy relies solely on the properties of scattered light and high-order nonlinear response of the luminescent labels, it can be applied to any speckle-forming propagation, from biological tissue to multicore fibers, combined with any type of phenomenon that exhibits a sufficiently high order nonlinearity.

physics.optics↗

arXiv2025

Survival of the fastest -- algorithm-guided evolution of light-powered underwater microrobots

Depending on multiple parameters, soft robots can exhibit different modes of locomotion that are difficult to model numerically. As a result, improving their performance is complex, especially in small-scale systems characterized by low Reynolds numbers, when multiple aero- and hydrodynamical processes influence their movement. In this work, we optimize light-powered millimetre-scale underwater swimmer locomotion by applying experimental results - measured swimming speed - as the fitness function in two evolutionary algorithms: particle swarm optimization and genetic algorithm. As these soft, light-powered robots with different characteristics (phenotypes) can be fabricated quickly, they provide a great platform for optimisation experiments, using many competing robots to improve swimming speed over consecutive generations. Interestingly, just like in natural evolution, unexpected gene combinations led to surprisingly good results, including eight-fold increase in speed or the discovery of a self-oscillating underwater locomotion mode.

cs.RO↗

arXiv2023

Versatile, open-access opto-mechanics platform for optical microscopes prototyping

Prototype optical microscopes, built to pursue developments in advanced imaging techniques, need specific optomechanical constructions: preferably with high flexibility in the elements arrangement, easy access to the optical paths, straightforward integration with external optical subsystems - light sources and detectors - as well as good mechanical stability. Typically they are either built around an adapted commercial microscope body or as a home-built setup, based on standard optomechanical elements, and neither solution delivers the desired characteristics. We developed a series of versatile platforms for prototyping optical microscopes in various configurations that use folding mirror(s) to maintain the optical paths horizontal throughout most of the setup, thus enabling the use of standard optical components in the excitation and detection paths and, last but not least, increasing the laser safety of the optical system.

physics.ins-det↗

arXiv2019

Optical vortex torque measured with optically trapped microbarbells

Optical vortex beams carry orbital angular momentum and thus exert torque on illuminated objects. A dielectric microtool - a microbarbell - is used in a two-laser optical tweezers to measure the torque of a focused optical vortex. The tool was either freely rotating due to the applied torque or set into oscillations by the counteracting force. Four different trapping configurations provided different ways of sensing the torque and gave consistent results. The value of torque was determined by confronting the experimental results with numerical and analytical models.

physics.optics↗

arXiv2007

Heralded Generation of Ultrafast Single Photons in Pure Quantum States

We present an experimental demonstration of heralded single photons prepared in pure quantum states from a parametric downconversion source. It is shown that, through controlling the modal structure of the photon pair emission, one can generate pairs in factorable states and thence eliminate the need for spectral filters in multiple-source interference schemes. Indistinguishable heralded photons were generated in two independent spectrally engineered sources, and, by performing a Hong-Ou-Mandel interference between them without spectral filters at a raw visibility of 94.4%, their purity was measured to be over 95%.

quant-ph↗

arXiv2007

Time-frequency Domain Analogues of Phase Space Sub-Planck Structures

We present experimental data of the frequency resolved optical gating (FROG) measurements of light pulses revealing interference features corresponding to sub-Planck structures in phase space. For superpositions of pulses a small, sub-Fourier shift in the carrier frequency leads to a state orthogonal to the initial one, although in the representation of standard time-frequency distributions these states seem to have a nonvanishing overlap.

physics.optics↗

arXiv2005

Joint spectrum of photon pairs measured by coincidence Fourier spectroscopy

We propose and demonstrate a method for measuring the joint spectrum of photon pairs via Fourier spectroscopy. The biphoton spectral intensity is computed from a two-dimensional interferogram of coincidence counts. The method has been implemented for a type-I downconversion source using a pair of common-path Mach-Zender interferometers based on Soleil compensators. The experimental results agree well with calculated frequency correlations that take into account the effects of coupling into single-mode fibers. The Fourier method is advantageous over scanning spectrometry when detectors exhibit high dark count rates leading to dominant additive noise.

quant-ph↗