The characterization of Earth-like exoplanets and precision tests of cosmological models using next-generation telescopes such as the ELT will demand precise calibration of astrophysical spectrographs in the visible region, where […]
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![Nanophotonic lithium niobate waveguides. a, Geometry of a nanophotonic lithium niobate (LiNbO3) waveguide, showing the optical mode profile for the fundamental transverse electric field (TE) mode and a possible poling pattern with spatially variable poling period Λ. The extraordinary crystal axis is oriented along the x-direction to access the highest electro-optic tensor element of LiNbO3. b, Poling periods Λ required for quasi-phase matching of various nonlinear optical processes for waveguides of different (top) width as a function of the fundamental comb’s wavelength. SHG: second harmonic generation; SHG + F: sum-frequency generation of second harmonic and fundamental comb; THG + F: sum-frequency generation of third harmonic and fundamental comb; SHG + SHG: sum-frequency generation of the second harmonic. Higher-order phase matching with three-fold period Λ is indicated (the current fabrication limit only allows for Λ > 2 µm). c, Photograph of a waveguide in operation and scanning electron microscope image of the LiNbO3 on silica (SiO2). d,e,f,g, Examples of waveguide designs showing poling pattern (top), experimentally generated spectra for different input pulse energies provided by a 100 MHz, 80 fs mode-locked laser with central wavelength of 1560 nm (waveguide cross-section and on chip-pulse energy as indicated) and pyChi [57] simulation results (bottom) for a pulse energy of 50 pJ. -- astro-ph.IM](https://i0.wp.com/astrobiology.com/wp-content/uploads/2023/06/Ultraviolet.png?resize=1200%2C709&ssl=1)
Posted inAstrochemistry, Astronomy & Telescopes, Imaging & Spectroscopy, Nanotechnology & SynBio, Status Report
Ultraviolet Astronomical Spectrograph Calibration With Laser Frequency Combs From Nanophotonic Waveguides
Astronomical precision spectroscopy underpins searches for life beyond Earth, direct observation of the expanding Universe and constraining the potential variability of physical constants across cosmological scales.