Seminarium Optyczne
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2022-09-06 (Wtorek)
Zapraszamy do sali 0.06, ul. Pasteura 5 o godzinie 10:15 
dr Agnieszka Popiołek - Masajada (Wydz. Podstawowych Problemów Techniki Politechniki Wrocławskiej)Optical fields' phase singularities in optical measurements
2022-06-09 (Czwartek)
Zapraszamy na spotkanie o godzinie 10:15
mgr Alexander Krupiński-Ptaszek (IFD UW)Single Photon Avalanche Diode arrays in fluorescence microscopy
Single Photon Avalanche Diode (SPAD) arrays offer picosecond temporal resolution paired withspatial resolution and single photon sensitivity. This combination enables many modalities offluorescence microscopy to be realized in a single experimental setup, or even in the samemeasurement, which makes the setup intrinsically multimodal
Seminarium z użyciem połączenia internetowegohttps://zoom.us/j/97696726563(meeting ID: ID 97696726563, password: 314297)
2022-06-02 (Czwartek)
Zapraszamy na spotkanie o godzinie 10:15
Klaudia Zaręmba-Kopczyk (IFT UW)Ultracold mixtures of Cr and Li atoms: theoretical prospects for controlled atomic collisions and LiCr molecule formation
During the seminar, I will present the results of our theoretical investigation of the interatomicinteractions and ultracold collisions between chromium and lithium atoms. Using the coupledcluster and multireference configuration interaction methods, we calculate the potential energycurves and the permanent and transition electric dipole moments for the quartet, sextet, and octetelectronic states of the LiCr molecule correlated to the four lowest atomic dissociation limits. Weinvestigate the optical paths of forming deeply-bound LiCr molecules via photoassociation andstimulated Raman adiabatic passage. We propose precision measurements of the variation ofelectron-to-proton mass ratio using ultracold LiCr molecules. We predict the scattering lengths forthe ultracold spin-polarized Cr+Li collisions (37+29-22 bohr for 53Cr+6Li) governed by the a 8Σ+electronic state without any adjustment to experimental data and in good agreement with recentexperimental measurements. Finally, we calculate magnetically tunable Feshbach resonances forultracold 52Cr+6Li and 53Cr+6Li collisions and assess prospects for magnetoassociation into polarand highly magnetic LiCr molecules.
Seminarium z użyciem połączenia internetowegohttps://zoom.us/j/97696726563(meeting ID: ID 97696726563, password: 314297)
2022-05-26 (Czwartek)
Zapraszamy na spotkanie o godzinie 10:15
prof. Wiesław Królikowski (Research School of Physics Australian National University Canberra, Australia)Nonlinear photonic crystals
2022-05-19 (Czwartek)
Zapraszamy na spotkanie o godzinie 10:15
Stanisław Kurdziałek (IFT UW)Back to sources—the role of losses and coherence in super-resolution imaging revisited
Photon losses are intrinsic for any translationally invariant optical imaging systemwith a non-trivial Point Spread Function, and the relation between the transmissionfactor and the coherence properties of an imaged object is universal – we demonstratethe rigorous proof of this statement, based on the principles of quantum mechanics.The fundamental limit on the precision of estimating separation between two partiallycoherent sources is then derived. The careful study of the role of photon losses allowsto resolve conflicting claims present in previous works. We compute the QuantumFisher Information for the generic model of optical 4f imaging system, and use priorconsiderations to validate the result for a general, translationally invariant imagingapparatus.
Seminarium z użyciem połączenia internetowegohttps://zoom.us/j/97696726563(meeting ID: ID 97696726563, password: 314297)
2022-05-12 (Czwartek)
Zapraszamy na spotkanie o godzinie 10:15
Alessio Ciamei (INO-CNR & LENS)Resonantly interacting Fermi mixtures of Li6 and Cr53 and formation of ultracold Li6Cr53 Feshbach dimers
We report on the realization of resonantly interacting Fermi mixtures of Li6 and Cr53atoms and the formation of Li6Cr53 bosonic Feshbach dimers. Employing a set of50 Feshbach resonances, observed in several spin combinations between 0 G and1500 G, we develop an accurate quantum collisional model for our system. From thiswe derive scattering lengths and unobserved resonance locations for Li6-Cr53, andprovide accurate predictions for the collisional properties of other Li-Cr isotopicpairs. We identify and characterize a set of strong s-wave resonances, essentiallyimmune to two-body inelastic losses, and obtain a magnetic field width of about0.5 G, in agreement with our model prediction. Exploiting one of these resonances,we show resonant tuning of inter-species elastic interactions in a thermal sample.Finally, we explain how we can reach simultaneous quantum degeneracy in ourmixture, and magneto-associate up to 30·103 Li6Cr53 Feshbach dimers. Our workpaves the way to the observation of novel few- and many-body phenomena in mass-imbalanced Fermi gases, and to the realization of ultracold samples of Li6Cr53ground-state molecules featuring both electric and magnetic dipole moments.
Seminarium z użyciem połączenia internetowegohttps://zoom.us/j/97696726563(meeting ID: 97696726563, password: 314297)
2022-04-28 (Czwartek)
Zapraszamy na spotkanie o godzinie 10:15
dr Tijs Karman (Radboud University Nijmegen)Sticking of Ultracold Molecules
Ultracold polar molecules are a promising platform for upcoming quantum technologiessuch as quantum computing and quantum simulation. However, applications are limited byloss due to molecule-molecule collisions. Surprisingly, such loss is observed even forchemically stable molecules. This is attributed to "sticky collisions"; The formation ofparticularly long-lived collision complexes that mediate the loss.In this talk, I will discuss our current understanding of these sticky collisions. I willshow conservation of angular momentum in collisions leads to sticking times orders ofmagnitude below previous estimates [1], but that excitation of collision complexes by thetrapping laser is fast and can explain the observed loss. These predictions are validatedquantitatively by two independent experiments [2], but fail to describe others [3]. It hasbeen speculated that in the latter experiments total angular momentum and molecularhyperfine states might not be conserved, extending sticking times by orders of magnitude.I will present a theoretical framework to study the dynamics of sticky collisions, whichshows small static electric fields can lead to non-conservation of angular momentum whilenuclear spin is typically conserved [4].[1] Christianen, Zwierlein, Groenenboom, and Karman, PRL, 123, 123402 (2019)[2] Liu et al. Nature Physics, 16, 1132 (2020)[3] Bause et al. PRR, 3, 033013 (2021)[4] Man, Groenenboom, and Karman arXiv 2203.13598
Seminarium z użyciem połączenia internetowegohttps://zoom.us/j/97696726563(meeting ID: 97696726563, password: 314297)
2022-04-21 (Czwartek)
Zapraszamy na spotkanie o godzinie 10:15
dr Michał Parniak (Centrum Nowych Technologii Uniwersytetu Warszawskiego)Atomic and optomechanical systems in the quantum regime
I will discuss the practical challenges in bringing atomic and mechanical systems todistinctively quantum states, i.e. entangled or close to ground state. Furthermore, lightturns out to be a perfect control tool, allowing cooling and readout of quantum states. Suchstates, being in many aspects macroscopic, are both interesting fundamentally and maybe applied for protocols such as sensing or communication. I will present experimentalresults from labs in Copenhagen along with fresh insights from our labs in Warsaw inefficient generation of light-matter entanglement.
Seminarium z użyciem połączenia internetowegohttps://zoom.us/j/97696726563(meeting ID: 97696726563, password: 314297)
2022-04-07 (Czwartek)
Zapraszamy na spotkanie o godzinie 10:15
Damian Michalik (Instytut Geofizyki WF UW)Free-form nanostructured core optical fibers
The lecture will present the potential of free-form refractive index modification in optical fibers based on thenanostructurizaton method, mainly in the telecommunication sector. Considering the current research state,possibilities of methods used so far, four types of free-form optical fibers were proposed; hybrid optical fiber,polarization-maintaining fiber, large mode area polarization-maintaining fiber, and few-mode fiber. Allstructures are composed of pure silica glass elements with appropriate doping levels of germanium dioxideand possibly fluorine. In this way, the refractive index of silica glass can be increased (GeO2) or decreased(F), making it possible to modify the optical fiber parameters. By using these types of glass, the positiveaspects of low attenuation and thermal matching during processing are simultaneously preserved. Thepresented fibers have been optimized and numerically tested. Two of the proposed fibers were fabricated bya modified stack-and-draw technology and studied experimentally
Seminarium użyciem połączenia internetowegohttps://zoom.us/j/97696726563(meeting ID: 97696726563, password: 314297)
2022-03-31 (Czwartek)
Zapraszamy na spotkanie o godzinie 10:15
Mateusz Mazelanik (Centrum Nowych Technologii Uniwersytetu Warszawskiego)Quantum memory-enabled super-resolution spectrometer
We bring super-resolution methods known from imaging to the spectral domain and demonstrate aspectrometer that operates beyond the Fourier limit. The spectrometer is based on a quantummemory with built-in processing capabilities, that implements a time-axis inversion interferometerallowing optimal measurement for two closely-spaced spectral lines. This is accomplished byengineering a frequency-dependent dispersion combined with time-dependent temporal phasemodulation that allows us to split, rotate and interfere the signal pulses in the chronocyclic space.Analysis based on quantum metrology shows the advantage of our technique over bothconventional spectroscopy as well as heterodyne measurements
Seminarium z użyciem połączenia internetowegohttps://zoom.us/j/97696726563(meeting ID: 97696726563, password: 314297)
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