We demonstrate, to our knowledge, the first on-chip heterodyne interferometer fabricated on a 300-mm CMOS compatible process that exhibits root-mean-square (RMS) position noise on the order of 2 nm. Measuring 1 mm by 6 mm, the interferometer is also, to our knowledge, the smallest heterodyne interferometer demonstrated to date and will surely impact numerous interferometric and metrology applications, including displacement measurement, laser Doppler velocimetry and vibrometry, Fourier transform spectroscopy, imaging, and light detection and ranging (LIDAR). Here we present preliminary results that demonstrate the displacement mode.
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http://dx.doi.org/10.1364/OL.40.003097 | DOI Listing |
This article covers the in-vessel design of the SPARC interferometry diagnostic system, highlighting unique aspects of the systems design and port plug integration in preparation for "day-1" plasma operations as a critical diagnostic for density feedback control. An early decision for the diagnostic was to deploy two lasers in the infrared wavelength spectrum, allowing the system to have a higher optical throughput. The optimization of the in-vessel geometry for the diagnostic follows a similar approach, focusing on de-risking possible damage to the plasma facing optical components by moving them further from the plasma with an orientation that provides a greater possibility for protective features to be added.
View Article and Find Full Text PDFInterferometric LiDAR is a device that is used to achieve distance, velocity and phase estimation with high precision and resolution through the use of frequency-modulated continuous wave (FMCW). In this instance, we study quantum enhancement detection techniques for a Mach-Zender interferometer with a FMCW coherent state input. Various quantum detection methods-including NOON state detection, coincidence detection, and sum of parity detection-are applied to the FMCW coherent state and compared against the classical heterodyne detection technique.
View Article and Find Full Text PDFSci Rep
September 2024
Institut für Experimentalphysik, Universität Hamburg, 22761, Hamburg, Germany.
Compact laser interferometers with large dynamic range are one of the core emerging tools to improve low frequency performance in gravitational wave detectors by providing local displacement sensing with sub 1 precision. Strong sinusoidal frequency modulations are used in such laser interferometers to create heterodyne-like photodetector signals from which the phase and other parameters, such as the absolute distance, can be extracted. The nested sinusoidal function in such signals is a challenge for the real-time parameter estimation in low-noise applications.
View Article and Find Full Text PDFRev Sci Instrum
September 2024
Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China.
The formation of a plasma sheath on the surface of spacecraft or satellites during high-speed atmospheric entry is a significant factor that affects communication and radar detection. Experimental research apparatus for electromagnetic science can simulate this plasma sheath and study the interaction mechanisms between electromagnetic waves and plasma sheaths. Electron density is a crucial parameter for this research.
View Article and Find Full Text PDFPhys Rev Lett
August 2024
OzGrav, Centre for Gravitational Astrophysics, Research School of Physics and Research School of Astronomy and Astrophysics, Australian National University, Australian Capital Territory, Australia.
Conventional heterodyne readout schemes are now under reconsideration due to the realization of techniques to evade its inherent 3 dB signal-to-noise penalty. The application of high-frequency, quadrature-entangled, two-mode squeezed states can further improve the readout sensitivity of audio-band signals. In this Letter, we experimentally demonstrate quantum-enhanced heterodyne readout of two spatially distinct interferometers with direct optical signal combination, circumventing the 3 dB heterodyne signal-to-noise penalty.
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