Conference Agenda

We demonstrate an achromatic optical Fourier transform (FT) system based on a symmetric triplet configuration combining diffractive and non-dispersive lenses. The approach compensates for chromatic dispersion by ensuring wavelength-independent spatial scaling and a common back focal plane. Experimental results show a strong reduction of chromatic aberrations compared to a single diffractive lens, evidenced by the spatial overlap of broadband FT patterns and improved correlation between spectral components. Additionally, the symmetry properties of GP lenses enable a compact reflective implementation using a single GP lens and a mirror, preserving the achromatic performance.

We present a computationally efficient all-in-focus image fusion algorithm for z-stack microscopy data of biological samples. We employ the Modulus of Gradient of Color planes (MGC), which aggregates gradient magnitudes from all three RGB channels to provide a robust per-pixel sharpness assessment across the stack. The fused all-in-focus output is reconstructed by sampling the original stack at these optimal depths. Compared to conventional multi-focus fusion methods, our algorithm achieves significantly faster execution due to its per-pixel maximum operation. The experimental results show that high-quality fusion can be achieved using fewer computational resources, making our method suitable for real-time or high-throughput microscopy applications. The algorithm generates both a fully in-focus composite image and a 3D height map of the sample surface.

An electromagnetic interference (EMI)-immune fiber-optic sensor is proposed for hotspot mapping in electronic packaging. By employing a high-numerical aperture (NA) three-fiber probe with a 1-excitation-2-collection topology, the system achieves significantly higher signal-to-noise ratios (SNR) than standard single-mode fiber (SMF) designs. Quantum dots (QDs) enable precise, emissivity-independent thermal sensing via wavelength shifts. This localized sensing strategy offers a robust alternative to infrared thermography.

Quantum photonic applications in cryptography, communication and computing are being driven by scalable sources of quantum light, such as single photons or pairs of entangled photons. Semiconductor quantum dots (QDs) are single-atom-like deterministic emitters providing the possibility to achieve on-demand triggering as well as high photon rate and fidelity of entanglement simultaneously. Currently, complex and bulky Ti:Sapphire pulsed lasers and optical parametric oscillators are used as pump sources for QD excitation. Towards this end, a CMOS-compatible photonic integrated circuit (PIC)-based pulsed laser source emitting mode-locked pulses at 940 nm for resonant pumping of InAs/GaAs QDs is proposed. We demonstrate a passively mode-locked laser diode based on an InGaAs/AlGaAs quantum well heterostructure, producing a ~19 GHz pulse train corresponding to a frequency comb around 940 nm. Currently work is ongoing to lower the repetition rate of mode-locked pulses to <5 GHz in order to match the spontaneous emission rate of QDs. This will be achieved by hybrid integration of the gain chip with a long extended cavity on a Si3N4 PIC leveraging low-loss passive waveguides and integrated phase tuners to fine-tune the wavelength and repetition rate.