Ultra-broadband quantum infrared spectroscopy

新開発の量子もつれ光源により、世界最大の超広帯域量子赤外分光を実現 --広帯域赤外分光の小型・高感度化に貢献--. 京都大学プレスリリース. 2024-01-18.Lights, detector, action!: KyotoU develops wider bandwidth quantum infrared spectroscopy. 京都大学プレスリリース. 2024-01-25.Spectroscopy in the mid-infrared region is an indispensable tool for identifying molecular types in various fields, including physics, chemistry, and medical sciences. However, conventional infrared light sources, detectors, and noise from blackbody radiation have been the obstacles to miniaturization and higher sensitivity of infrared spectrometers. Quantum infrared spectroscopy, which uses visible and infrared photon pairs in a quantum entangled state, has attracted attention as a new sensing technology that enables infrared spectroscopy with detectors in the visible range. However, the bandwidth of conventional quantum entangled light sources is at most 1 µm or less, which hinders broadband measurements, which are important in spectroscopic applications. Here we have realized an ultra-broadband entangled state of visible–infrared photons with wavelengths from 2 to 5 µm, harnessing a specially designed nonlinear crystal with chirped poling structure inside. Furthermore, we constructed a nonlinear quantum interferometer using the ultra-broadband quantum entangled photons and realized broadband infrared spectroscopy of inorganic and organic materials using a visible detector made of silicon. Our results show that quantum infrared spectroscopy can achieve ultra-broadband spectroscopic measurements and pave the way for the highly sensitive, ultra-compact infrared spectrometers using quantum entangled photons

Quantum sensing with integrated waveguides for ultra-fast spectroscopy in the mid infra-red

Die Entwicklung praktischer Quanten-Sensoren für Anwendungen auf dem Gebiet der ultra-schnellen Spektroskopie bedingt deren Integration. In dieser Dissertation nutzen wir integrierte Wellenleiter als Photonenpaar-Quellen basierend auf parametrischer Fluoreszenz (PF) für ultra-schnelle Quanten-Spektroskopie in nichtlinearen Interferometern. Dazu müssen diese Quellen zugleich spektral breitbandige und weit separierte Photonen erzeugen. Integrierte Quellen sind jedoch oft aufgrund ihrer langen Interaktionslänge in der Bandbreite beschränkt. Zuerst überwinden wir daher diese Beschränkung durch Dispersions-Anpassung und stellen zwei Realisierungen periodisch gepolter, Titan-ein-diffundierter Lithium-Niobat-Wellenleiter vor, welche breitbandige PF mit ungleichen Wellenlängen im nahen und mittleren Infrarot erzeugen. Danach verwenden wir unsere erste Quelle in einem nichtlinearen Interferometer. Basierend auf der theoretischen Beschreibung des Systems, messen wir direkt die Korrelationszeit des Photonenpaares, ein wichtiges Maß für deren Gleichzeitigkeit und die zeitliche Auflösung in Experimenten. Im Folgenden untersuchen wir zwei gebräuchliche Realisierungen nichtlinearer Interferometer auf deren Eignung für quanten-optische Kohärenztomographie mit integrierten Quellen. Schließlich nutzen wir die zweite Quelle für Absorptionsmessungen im mittleren Infrarot, bei denen lediglich Photonen im nahen Infrarot detektiert werden.The development of practical quantum sensors for applications in ultra-fast spectroscopy necessitates their integration. In this thesis, we use integrated waveguides as photon pair sources based on parametric down-conversion (PDC) to perform quantum spectroscopy with nonlinear interferometers. This requires the PDC sources to be broadband and highly non-degenerate. However, non-degenerate integrated sources are typically limited in bandwidth due to their long interaction length. First, we overcome this limitation by dispersion-engineering and present two realisations of periodically poled, titanium in-diffused lithium niobate waveguides that generate spectrally broadband photon pairs at non-degenerate wavelengths in the near and mid infra-red. Next, we employ the first PDC source as building block of a nonlinear interferometer. Based on our theoretical description of the system, we perform direct measurements of the bi-photon correlation time, an important metric that defines their simultaneity and the temporal resolution in a measurement. In the following, we investigate the properties of two common geometries for nonlinear interferometers regarding their benefits, disadvantages, and optimal operation mode for quantum optical coherence tomography when working with integrated waveguide PDC sources. Finally, we use the second PDC source in a nonlinear interferometer to perform absorption spectroscopy in the mid infra-red, while only detecting in the near infra-red.vorgelegt von Franz Hartmut Roeder ; Erstgutachter: Prof. Dr. Christine Silberhorn, Zweitgutachter: Prof. Dr. Thomas Zentgraf, Vertreter des Mittelbaus: Dr. Frederik Thiele, Vorsitzender der Prüfungskommission: Prof. Dr. Wolf Gero SchmidtTag der Verteidigung: 11.04.2025Universität Paderborn, Dissertation, 202

Terahertz Technology for Defense and Security-Related Applications

This thesis deals with chosen aspects of terahertz (THz) technology that have potential in defense and security-related applications. A novel method for simultaneous data acquisition in time-resolved THz spectroscopy experiments is developed. This technique is demonstrated by extracting the sheet conductivity of photoexcited charge carriers in semi-insulating gallium arsenide. Comparison with results obtained using a standard data acquisition scheme shows that the new method minimizes errors originating from fluctuations in the laser system out-put and timing errors in the THz pulse detection. Furthermore, a new organic material, BNA, is proved to be a strong and broadband THz emitter which enables spectroscopy with a bandwidth twice as large as conventional spectroscopy in the field. To access electric fields allowing exploration of THz nonlinear phenomena, field enhancement properties of tapered parallel plate waveguide

Review: far-infrared instrumentation and technological development for the next decade

Far-infrared astronomy has advanced rapidly since its inception in the late 1950s, driven by a maturing technology base and an expanding community of researchers. This advancement has shown that observations at far-infrared wavelengths are important in nearly all areas of astrophysics, from the search for habitable planets and the origin of life to the earliest stages of galaxy assembly in the first few hundred million years of cosmic history. The combination of a still-developing portfolio of technologies, particularly in the field of detectors, and a widening ensemble of platforms within which these technologies can be deployed, means that far-infrared astronomy holds the potential for paradigm-shifting advances over the next decade. We examine the current and future far-infrared observing platforms, including ground-based, suborbital, and space-based facilities, and discuss the technology development pathways that will enable and enhance these platforms to best address the challenges facing far-infrared astronomy in the 21st century

Gamma-ray flaring activity from the gravitationally lensed blazar PKS 1830-211 observed by Fermi LAT

The Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope routinely detects the highly dust-absorbed, reddened, and MeV-peaked flat spectrum radio quasar PKS 1830-211 (z=2.507). Its apparent isotropic gamma-ray luminosity (E>100 MeV) averaged over $\sim$ 3 years of observations and peaking on 2010 October 14/15 at 2.9 X 10^{50} erg s^{-1}, makes it among the brightest high-redshift Fermi blazars. No published model with a single lens can account for all of the observed characteristics of this complex system. Based on radio observations, one expects time delayed variability to follow about 25 days after a primary flare, with flux about a factor 1.5 less. Two large gamma-ray flares of PKS 1830-211 have been detected by the LAT in the considered period and no substantial evidence for such a delayed activity was found. This allows us to place a lower limit of about 6 on the gamma rays flux ratio between the two lensed images. Swift XRT observations from a dedicated Target of Opportunity program indicate a hard spectrum and with no significant correlation of X-ray flux with the gamma-ray variability. The spectral energy distribution can be modeled with inverse Compton scattering of thermal photons from the dusty torus. The implications of the LAT data in terms of variability, the lack of evident delayed flare events, and different radio and gamma-ray flux ratios are discussed. Microlensing effects, absorption, size and location of the emitting regions, the complex mass distribution of the system, an energy-dependent inner structure of the source, and flux suppression by the lens galaxy for one image path may be considered as hypotheses for understanding our results.Comment: 14 pages, 6 figures, 2 tables. Accepted by the The Astrophysical Journal. Corresponding authors: S. Ciprini (ASI ASDC & INAF OAR, Rome, Italy), S. Buson (INAF Padova & Univ. of Padova, Padova, Italy), J. Finke (NRL, Washington, DC, USA), F. D'Ammando (INAF IRA, Bologna, Italy

Instrument and method for X-ray diffraction, fluorescence, and crystal texture analysis without sample preparation

An X-ray diffraction and X-ray fluorescence instrument for analyzing samples having no sample preparation includes a X-ray source configured to output a collimated X-ray beam comprising a continuum spectrum of X-rays to a predetermined coordinate and a photon-counting X-ray imaging spectrometer disposed to receive X-rays output from an unprepared sample disposed at the predetermined coordinate upon exposure of the unprepared sample to the collimated X-ray beam. The X-ray source and the photon-counting X-ray imaging spectrometer are arranged in a reflection geometry relative to the predetermined coordinate

Resolution limits of quantum imaging with undetected light and optimization towards application

Quantenbildgebung ermöglicht verbesserte Bildgebung über klassische Bildgebungsgrenzen hinaus. Insbesondere erlaubt die Quantenbildgebung mit nicht-detektiertem Licht (QIUL) die Aufnahme von Bildern eines Objekts mit Licht, welches nicht mit dem Objekt interagiert hat. QIUL kann mittels verhältnismäßig einfacher experimenteller Aufbauten realisiert werden und ermöglicht die Beleuchtung mit geringen Photonendosen. Weiterhin eröffnet QIUL neue Bildgebungsmöglichkeiten durch die Verwendung unterschiedlicher Wellenlängen für Beleuchtung und Detektion. Diese Dissertation behandelt zwei Hauptthemen. Erstens wird die Bewertung von QIUL-Systemen aus einer angewandten Perspektive betrachtet. Der Übergang von Mach-Zehnder- zu Michelson-Interferometern reduziert die Systemgröße und -komplexität, erleichtert die Feinjustage und verbessert die Toleranz gegen Fehljustierungen. Ein effizientes System, welches eine hohe Aufnahmegeschwindigkeit von Echtzeitbildern erlaubt, wird ebenfalls vorgestellt. Weiterhin werden holografische Bildaufnahmetechniken erstmals im Kontext von QIUL implementiert. Der zweite Aspekt der Arbeit untersucht die Einflüsse der Parameter welche für die Erzeugung von verschränkten Photonenpaaren relevant sind, insbesondere Kristalllänge und Pumpstrahlradius, auf die Bildauflösungsqualität in QIUL-Systemen basierend auf Orts-Korrelationen. In dieser Dissertation wird die erste experimentelle Auflösungsanalyse für ein solches System präsentiert, welche Diskrepanzen zu bestehenden theoretischen Modellen in der Literatur aufzeigt. Eine Erweiterung der theoretischen Modelle wurde entwickelt, welche das komplexe Wechselspiel aus Pumpstrahlradius und Kristalllänge besser beschreibt und die experimentellen Ergebnisse konsistent erklären kann. Zudem wird ein Vergleich der Auflösungsfähigkeiten zwischen Impuls- und Orts-Korrelationen durchgeführt, um neue Einblicke für die Optimierung von QIUL-Systemen zu bieten

Construction of an enzyme-free electrochemical sensor based on Ag-Fe2O3/POM/RGO novel nanocomposite for hydrogen peroxide detection

>Magister Scientiae - MScThe motivation to determine H2O2 lies in the fact that this chemical species plays a crucial role in diverse fields of practise such as cosmetic, food, diagnostic, pharmaceutical, clinical and environmental protection industries. Several methods such as chromatography, colorimetry, titrimetry and spectrophotometry have been developed for its detection. However, these methods are known to manifest underlying disadvantages such as high cost, time consuming, instability and complicated immobilization procedures. In this present study an enzyme-less electrochemical sensor based on Ag-Fe2O3/POM/RGO nanocomposite (POM stands for polyoxometalate and RGO stands for reduced graphene oxide) was successfully synthesised via a hydrothermal method and a photochemical reduction method for the detection of hydrogen peroxide (H2O2)