The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
We study [1] the application potential of CdSe nanoplatelets (NPLs) [2], a model system for colloidal 2D materials, as field-controlled emitters and their properties. We show that their luminescence emission can be modulated by 28% upon application of electrical fields up to 175 kV/cm. This is a very high modulation depth for field-controlled nanoemitters. Based on our experimental results we estimate...
We report the new method for the measurement of the phase-relaxation time T2 of a medium with femtosecond time resolution. The method is based on the effect of quantum interference of entangled photons and does not require the actual use of a femtosecond light source. The method provides the practical and cost-efficient alternative to existing methods of ultrafast time-resolved spectroscopy [1].
Hydrogen molecular ions play an important role for accurate quantum electrodynamics calculations of rovibrational energy levels [1] and the comparison with laser spectroscopy results [2] allowed probing fundamental physics constants and laws. Advances are driven by an accurate control of the external and internal molecular degrees of freedom with a wide range of techniques [3]. Experimental setups...
Precision spectroscopy in the mid-infrared (MIR) region is of great importance for many applications including breath diagnosis and astronomical spectroscopy as various molecular vibrational modes exist in this region. A mid-infrared comb combined with a broadband comb-resolved spectrometer can be a promising method to do this since target gas contains multiple molecular species in most applications...
Accurate molecular spectroscopy in the mid-infrared (mid-IR) region allows precision measurements with applications in fundamental physics. We present our on-going work towards measuring absolute vibrational frequencies of various polyatomic species — in particular methanol — around 10 μm, at an unprecedented level of accuracy, using a both ultra-stable and widely tuneable near-infrared frequency...
Quantum-electrodynamics (QED) theory has been tested with high accuracy [1]. However, QED tests in atomic hydrogen are currently limited by the experimentally determined value of the proton charge radius. Therefore spectroscopic measurements were conducted with muonic-atoms (μH and μD) to determine the proton and the deuteron charge radii with an order of magnitude higher accuracy. However, these...
Mid-infrared (MIR) vibrational spectroscopy is a versatile tool for identifying organic compounds (OC) in gases or liquids in a label-free manner due to their unique molecular fingerprint, promoting a large variety of applications in biology, chemistry, medicine or environmental monitoring. Although new technologies like quantum-cascade lasers are rapidly evolving, the workhorse in this field is still...
Attosecond-streaking spectroscopy [1], has given real-time access to photoionization delays of atoms in the gas phase [2], and the additional effects of electron transport processes through atomic layers and interfaces of solid-state systems [3, 4]. Here, we report on the first attosecond-streaking experiments on liquid samples. We have realized attosecond-streaking photoelectron spectroscopy on water...
Fourier-transform (FT) spectrometers [1] are widely employed in the infrared spectral region (FTIRs) due to the lack of cheap multiplex detectors. They use an interferometer (usually a Michelson) to create two time-delayed replicas of the incoming light. A single-pixel detector then records an interferogram (i.e. the overall incident energy as a function of the optical path difference)· whose FT directly...
With upconversion based mid-infrared reflection spectroscopy we have proved it possible to differentiate between several common types of black plastics. This allow for the possibility of efficient sorting of black plastics in clean fractions, paving the road for both economically viable and ecologically sustainable recycling.
Through generation of coherent extreme ultraviolet (XUV) radiation, high-harmonic generation (HHG) has opened up a wealth of possibilities for table-top research, ranging from attosecond dynamics to high resolution coherent imaging. The ability to perform interferometry with HHG sources would enable powerful coherent optical techniques such as Fourier transform spectroscopy in the XUV spectral range...
Strong light-matter interaction leads to the appearance of new states, i.e. exciton-polaritons, with photophysical properties rather distinct from their constituents. Recent developments in fabrication techniques allow us to make metallic structures with strong electric field confinement in nanoscale mode volumes, allowing for a facile assembly of strongly coupled systems at room temperature based...
Hybrid perovskite semiconductors have attracted strong scientific interest for optoelectronic applications. Despite the current drive for higher optoelectronic device efficiencies and stabilities, little information exists about the fundamental non-equilibrium interactions of photo-excited charge carriers in these materials. Time-resolved experiments with ultrashort laser pulses have been used to...
Astronomical spectrographs combining high resolution (R >> 10, 000) with high stability provide unique scientific capabilities, e.g. for observing the small Doppler shifts which are signatures of Earth-like exoplanets or sensitively measuring isotopic ratios in ancient stars to reveal details of the early universe. Laser frequency combs with mode spacings from 12.5–50 GHz [1] have been shown...
Optical frequency combs (OFCs) have led to an impressive number of achievements, including multi-heterodyne spectroscopy [1]. Mode-locked OFCs have been widely used due to their exceptional spectral bandwidth, but they usually require sophisticated locking methods to control the free spectral range (FSR) and the absolute frequency of the comb. A promising alternative is provided by electro-optic OFCs,...
Two-dimensional electronic spectroscopy (2DES) is a powerful spectroscopic technique for the study of energy and charge flow in biological systems, which has been successfully applied in the visible and infrared ranges. Its extension to the UV range (2DUV) is extremely promising for the study of biomolecules but poses several technical challenges: (i) the requirement of phase-locked pulse pairs; (ii)...
Mode-locked lasers are a paramount example of dissipative nonlinear systems that support bound-states of multiple sohtons [1, 2]. However, rapid dynamic interactions between sohton complexes with pico-to femtosecond separation are mostly inaccessible to standard laser characterization techniques, including scanning interferometric autocorrelation, temporally-averaging spectroscopy or single-shot measurements...
Fourier transform (FT) spectroscopy [1] is a powerful technique to measure spectra in the time domain. With respect to frequency-domain spectrometers, FT spectrometers have the advantage of higher signal to noise ratio and optical throughput, and the possibility to adjust the frequency resolution. FT spectroscopy requires to generate two field replicas whose delay must be scanned with accuracy of...
Optical frequency combs (OFCs) generated by quantum cascade lasers (QCLs) have recently been proven in the mid infrared [1] and they have already been applied to spectroscopy in free-running operation [2]. It is clear however that for more demanding applications such as high-resolution and accuracy spectroscopy and metrology the performance obtained in free-running operation is not enough, since a...
We report on metrological-grade saturated absorption spectroscopy of CHF3 at 8.63 μm based on CW distributed-feedback QCL laser and a mid-IR self-frequency referenced optical comb. The experimental setup for the saturation spectroscopy of CHF3 is shown in Fig. 1. A CW DFB-QCL with a maximum output power of ∼40 mW tunable in the wavelength range from 8.55 to 8.65 μm, in coincidence with the us (asymmetric...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.