Our team aims to demonstrate a photonic Quantum-Inspired Imager (QI2) which provides source reconstruction below the optical/NIR diffraction limit in the presence of atmospheric turbulence without the need for adaptive optics. Turbulent cells in the atmosphere reduce image resolution by causing fluctuations in the phase of propagating wavefronts. Rather than relying on conventional methods of wavefront sensing, our approach leverages the spectral diversity inherent in the factors which limit resolution, thus breaking the degeneracy between these aberrating processes. Though this concept has long been employed in astronomy to achieve diffraction limited imaging, our approach achieves this necessary spectral diversity with a passive photonic lantern mode multiplexer that converts a multimode wavefront input into an array of spatially distinct single-mode outputs, from which we can deduce the atmospheric phase variations and reconstruct the source function. We present detailed simulations and laboratory tests demonstrating the QI2 approach in measuring atmospheric turbulence and correcting phase distortions.
Fiber mode scrambling remains a key technology for fiber-fed EPRV measurements. Any change in mode excitation within the fiber will result in apparent centroid shifts (and thus artificial RV shifts) in the target spectrum. Technologies such as scramblers and mechanical agitators are currently used to mitigate this effect. Here, we present our experimental results on the modal illumination stability of “flat top” optical fibers. These fibers are fabricated with deliberately-introduced internal mode scrambling features which distribute light evenly among the fiber modes during transmission from input to output. Importantly, this scrambling occurs with minimal (few percent) light losses and without external optical alignment or mechanical motion to achieve excellent mode scrambling if the flat-top fiber is spliced into the existing fiber feed. We will present our measurements of flat-top fiber throughput and scrambling gain, and the expected benefits from incorporating such a fiber into existing EPRV spectrographs.
We present results from development of a photonic Quantum-Inspired Imager (QI2) providing source reconstruction below the optical/NIR diffraction limit through atmospheric turbulence without adaptive optics. Our group has demonstrated a photonic spatial mode sorter quantum-sensing device in practice — a photonic lantern — with capabilities in both spatial and spectral diversity, as well as future extensions to polarization sensitivity. Our team has developed high-efficiency photonic lantern mode-sorting/multiplexing devices fabricated in optical fibers. Our proposed passive imaging system is therefore based on three main innovations: (i) photonic lantern spatial mode sorters with spatial and spectral diversity, (ii) atmospheric blur removal enabled by mode-/wavelength-resolution, (iii) quantum-inspired image reconstruction techniques.
Multimode (MM) laser light has a vast application history spanning from laser pump sources, to high-speed optical links, to imaging systems but can suffer enormous inefficiencies when coupled through a solid core optical fiber for long transmission path lengths. One way to improve the MM transmission is by replacing the traditional solid-core fibers with uniquely tailored nested antiresonant hollow-core fibers (NANFs). By improving upon previous design methods, one can extend the application of the HCF to 100s of modes and beyond while maintaining low loss thus enabling novel concepts such as power beaming through fiber and the transmission of spatiotemporal tailored ultrafast wavepackets. We report a uniquely designed, fabricated, and tested MM NANF that enables low-loss transmission of 100s of modes.
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