Report

Teaser, summary, work performed and final results

Periodic Reporting for period 1 - Q-MIC (Quantum-enhanced on-chip interference microscopy)

Teaser

Light microscopes can detect objects through several physical processes, such as scattering, absorption, and reflection. However, in highly transparent samples the aforementioned mechanisms are often too weak to acquire high-contrast images. Differential interference contrast...

Summary

Light microscopes can detect objects through several physical processes, such as scattering, absorption, and reflection. However, in highly transparent samples the aforementioned mechanisms are often too weak to acquire high-contrast images. Differential interference contrast (DIC) microscopy is a technique that can be used to detect tiny optical path differences (phase shifts) in transparent materials. Though proposed more than 40 years ago by one of the consortium partners (ZEISS), DIC microscopy is still one of the most sensitive techniques today that allows detection of cells and protein layers. High-contrast microscopy is particularly challenging when illuminating light must be low intensity, to avoid damaging the sample or introducing measurement artefacts. When a dim classical light source is used to illuminate a sample, the minimum phase contrast (∆φ) in interferometric imaging configurations is given (for coherent light) by the shot noise limit ∆φ∝1/√N, where N is the number of photons propagating through the sample. However, this limit is not fundamental to all light sources; non-classical states of light can overcome it, through quantum-enhanced metrological schemes, which can achieve ultra-sensitive measurements, i.e. increased phase information per photon.
Q-MIC will have a significant scientific, technological and societal (industrial) impact in the field of quantum imaging and sensing, on-chip microscopy and detection of biological species. Q-MIC will pioneer and validate a new microscope and imaging platform exploiting the unique combination of DIC and quantum-enhanced metrology: a product of unprecedented sensitivity in the low power regime. Q-MIC´s breakthrough is a quantum enhanced imaging platform for transparent objects with unprecedented sensitivity and imaging volumes, through new lens-free interferometric design, highly efficient short wavelength quantum sources and single photon detector arrays.
The Q-MIC platform will reach unprecedented sensitivities (a few atomic layers, of the order of 1Ã…) over large field-of-view (tens of mm2) in the low light (single-photon) regime. This unique combination of features will allow, on the one hand, the first demonstration of a practical quantum device for imaging, while providing, on the other hand, a platform for fundamentally new lines of research in quantum metrology, including the interaction of quantum states and bio-species.
More specific objectives are the development of:
-Lens-free DIC microscopy at single-photon level.
-Quantum-enhancement in imaging with non-classical states of light.
-Short wavelength (<550nm) entangled photon source.
-Novel Single-Photon Avalanche Diode image sensor array (SPAD-ISA).
-Application to the material processing, photosensitive biomarkers and cells.

Work performed

During the first year, the consortium has focused on defining specific applications and requirements. These lead to specifications for the Q-MIC quantum imaging system and related components. Component development is also well underway and initial parts are ready for being assembled into first imaging system prototypes. More specifically:
-Specific applications in material processing control and quality and biological detection have been identified;
-The applications requirements can be met by the corresponding specifications of the designed imaging system;
-First generation of quantum sources of entangled photons, SPAD-ISA, and camera have been already developed.
-Quantum imaging in Hong-Ou-Mandel (HOM) and lens-free interferometric microscopy (LIM) configuration have been designed and preliminary tested.

Final results

a) Progress beyond the state of the art (SoA)
The following list include specific first year achievements that go all beyond SoA:
• Generation of photon pairs at wavelengths <600nm using a cw pump laser with pair emission rates in excess of 1 Million pairs/s, which is orders of magnitude beyond prior work has been accomplished;
• Large (96x96) SPAD array for photon coincidence with reduced power consumption and with a new micro-lens coupling optics with very high concentration factors has been designed;
• New SPAD array architecture (event-driven readout) that can provide addresses of pixels involved in photon coincidence, without post-processing;
• Detailed statistical analysis about expected single photon and coincidence rates, and first anticorrelation measurements using SPAD array have been completed have been carried out;
• New technology for distillation of quantum images from classical noise backgrounds has been developed;
• Quantum imaging approach that uses single photon cameras to isolate entangled photon pairs even in the presence of camera noise has been developed;
• Initial feasibility tests with the LIM of representative optical elements for extreme-ultraviolet-lithography systems and related has been carried out, These showed an axial sensitivity at least on par with currently employed metrology systems and higher for some spatial frequency ranges.
b) Expected potential impacts
Scientific: For the first time, be able to perform Quantum imaging in a compact form. This will allow to experimentally investigate the physics and potentials of quantum effects in a microscope platform and specially to provide new insights in the interaction of entangled photons and other quantum states with matter, like cells. In the first year, we have demonstrated that quantum image distillation can reduce noise and potentially become a key technology for quantum microscopy based on the HOM effect. The Q-MIC short-wavelength sources may open new possibilities for experiments involving measurements in a previously not accessible wavelength range.
Technological: Q-MIC will pioneer and validate a new microscope exploiting the unique combination of interferometry and quantum-enhanced metrology to deliver a product of unprecedented sensitivity in the low power regime: (i) extreme sensitivity detection over a large field of view and volume, well beyond those obtainable today even with sophisticated super-resolution microscopes and microarray laser scanners. (ii) New quantum sources, such as those to produce entangled photons and NOON states, SPAD image sensors and their integration. (iii) Radically new paradigm on how to develop SPAD imager building blocks of the next decade.
Industrial/societal: Q-MIC will address existing and future application fields. Work is in progress to demonstrate impact in biology, especially in the detection of photosensitive cells, which will require the development of the full system. However, during the first year, the consortium has already demonstrated the potential of the technology in several areas:
• The quantum distillation in lidar protocols, e.g. based on detection of entangled photons will require this technology in order to remove background and noise;
• The new microlens array may be used for several project SME partner (MPD) products fostering its revenues and market competitiveness;
• The LIM can enable critical process chains in the development of EUV-lithography systems. This is especially meaningful as the LIM has a comparatively large field of view and fast acquisition time, which makes it potentially better suited to be integrated into a workflow than other technologies;
• The LIM platform has also the potential to become also an economically competitive tool for the qualitative and quantitative inspection of transparent parts as an in line system.

Website & more info

More info: http://q-mic.eu/.