Exceeding octave tunable Terahertz waves with zepto-second level timing noise

Spectral purity of any millimeter wave (mmW) source is of the utmost interest in low-noise applications. Optical synthesis via photomixing is an attractive source for such mmWs, which usually involves expensive spectrally pure lasers with narrow linewidths approaching monochromaticity due to their inherent fabrication costs or specifications. Here, we report an alternative option for enhancing the spectral purity of inexpensive semiconductor diode lasers via a self-injection locking technique through corresponding Stokes waves from a fiber Brillouin cavity exhibiting greatly improved phase noise levels and large wavelength tunability of ~1.8 nm. We implement a system with two self-injected diode lasers on a common Brillouin cavity aimed at difference frequency generation in the mmW and THz region. We generate tunable sub-mmW (0.3 and 0.5 THz) waves by beating the self-injected two wavelength Stokes light on a uni-travelling carrier photodiode and characterize the noise performance. The sub-mmW features miniscule timing noise levels in the zepto-second (zs.Hz^-0.5) scale outperforming the state of the art dissipative Kerr soliton based micro-resonator setups while offering broader frequency tunability. These results suggest a viable inexpensive alternative for mmW sources aimed at low-noise applications featuring lab-scale footprints and rack-mounted portability while paving the way for chip-scale photonic integration.Comment: 31 page

Kinetic of biobased bitumen synthesis from microalgae biomass by hydrothermal liquefaction

The current worldwide consumption of bitumen is about 100 million tons. A remarkable combination of properties (adhesion, impermeability to water, specific thermo-rheological behavior) makes it a key material in road construction. Today’s bitumen is mostly obtained from petroleum refining, so bioabased alternatives have to be explored for the future. The ALGOROUTE project funded by the French National Agency for Research (ANR) focuses on the use of hydrothermal liquefaction (HTL) process for the production of bitumen mimicking binders from microalgae biomass. HTL applied to microalgae is inspired by the geological process of petroleum formation, but on a very short time scale: For conditions around 260 °C / 50 bar, bitumen like products have been obtained by our consortium for residence times of about 1 hour [1] [2]. Beside temperature and pressure, the key parameters are the reaction time, algae/water ratio and loading level of reactor. Please click Additional Files below to see the full abstract

In-depth, comprenhensive mapping of the human seminal plasma proteome by a novel, iterative LC/MS/MS/database search workflow

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Brillouin laser-driven terahertz oscillator up to 3 THz with femtosecond-level timing jitter

The terahertz (THz) frequency range, spanning 0.1 to 10 THz, is a field ripe for innovation with vast, developing potential in areas like wireless communication and molecular spectroscopy. Our work introduces a dual-wavelength laser design that utilizes stimulated Brillouin scattering in an optical fiber cavity to effectively generate two highly coherent optical Stokes waves with differential phase noise inherently mitigated. To guarantee robust operation, the Stokes waves are optically injected into their respective pump lasers, which also serves to greatly improve the resulting coherence. The frequency difference between the two wavelengths is converted into THz waves through a uni-traveling-carrier photodiode. This innovative design facilitates the generation of THz waves with phase noise levels of less than -100 dBc/Hz, translating to timing noise below 10~$\mathrm{as} / \sqrt{\mathrm{Hz}}$ at 10 kHz Fourier frequency, over a carrier frequency range from 300 GHz to 3 THz. This development in phase noise reduction establishes a new benchmark in the spectral purity of tunable THz sources. Such advances are pivotal for applications to move beyond oscillator constraints