Browsing by Subject "Microcavities"
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Item Open Access Conditions for observation of Rabi oscillations in an exciton-polariton system(Elsevier BV, 1995) Shumovsky, A. S.; Müstecaplioǧlu, Ö. E.The pure quantum model describing Rabi oscillations of exciton-polaritons (EP) in a micro-cavity with finite quality is considered. It is shown that the oscillations can be observed if the cavity damping rate does not exceed some critical value depending on the EP coupling constant and the detuning of the cavity mode. An explicit expression for the renormalized Rabi frequency is found. Comparison of the results with experimental data shows a good agreement. © 1995.Item Open Access Lasing modes of infinite periodic chain of quantum wires(IEEE, 2009-06-07) Byelobrov, V. O.; Benson, T. M.; Sewell, P.; Altıntaş, Ayhan; Nosich, A. I.In this paper, we study the scattering and eigenvalue problems for a periodic open optical resonator that is an infinite chain of active circular cylindrical quantum wires standing in free space. The scattering problem is solved by the method of partial separation of variables. The eigenvalue problem differs from the first one by the absence of the incident field and presence of "active properties" of cylinders and yields the frequencies and thresholds of lasing. ©2009 IEEE.Item Open Access Microcavity lasers on polymer materials: Boundary integral equation modeling and experiments(IEEE, 2015-04) Nosich, A.I.; Smotrova, E.I.; Lebental, M.; Sukharevsky Ilya O.; Altıntaş, AyhanWe consider the modeling and experiments with polymer dye-doped lasers shaped as thin flat cavities, allowing one to consider them as two-dimensional (2-D) active cavities. We focus our modeling on the H-polarized electromagnetic field in a kite-shaped laser. Assuming that the lasing-mode frequency is real-valued, we look for it together with the corresponding threshold value of material gain. Such electromagnetic-field problem is reduced to the Muller set of the boundary integral equations (MBIE), discretization of which yields determinantal equation. Numerical results reveal various types of modes existing in the kite including the perturbed whispering gallery (WG) modes that have the lowest thresholds. Their far-field emission patterns show good agreement with the measurements. © 2015 IEEE.Item Open Access Ultralow threshold laser action from toroidal polymer microcavity(American Institute of Phycsics, 2009) Tulek, A.; Akbulut, D.; Bayındır, MehmetWe report laser action from a toroidal microcavity coated with π-conjugated polymer. An ultralow threshold value of ∼200 pJ/pulse is achieved by free space excitation in ambient conditions. This is the lowest threshold energy obtained in microtoroid lasers by free space excitation. The effective refractive index of the polymer, extracted from Fourier analysis of emission spectra, is 1.787, which is very close to measured value of 1.790 indicating that laser modes are located around the circumference of the cavity as whispering gallery resonances. © 2009 American Institute of Physics.Item Open Access Ultrasensitive label-free microcavity biosensors with high selectivity(IEEE, 2011) Özgür, Erol; Bayındır, Mehmet; Aktaş, OzanHigh quality factor whispering gallery mode microresonators have been recently shown to exhibit detection sensitivity of single molecule; however, the selectivity of these sensors among different types of analytes remains as an important issue, obscuring the broad applicability of optical microcavities. We demonstrate a surface modification strategy for fabrication of high selectivity and sensitivity microcavity biosensors in this study. © 2011 IEEE.Item Open Access Unidirectional laser emission from π-conjugated polymer microcavities with broken symmetry(2007) Tulek, A.; Vardeny, Z.V.We report unidirectional laser emission from π-conjugated polymer microcavities with broken symmetry geometries such as spiral and microdisk containing a "line defect," in comparison with plain microdisk cavity having isotropic emission. We found that the laser emission directionality contrast ratio is 8-10 and far field lateral divergence angle is 12°-15° for both broken symmetry geometries, with no significant increase in the laser threshold intensity. Fourier transform analysis of the laser emission spectra shows that unlike microdisks with line defect, the variation of light trajectories in the spiral microcavities leads to less defined laser modes. © 2007 American Institute of Physics.Item Open Access Wafer-scale arrays of high-Q silica optical microcavities(OSA - The Optical Society, 2017) Ozgur E.; Huseyinoglu E.; Dana, A.On-chip high-Q microcavities possess significant potential in terms of integration of optical microresonators into functional optoelectronic devices that could be used in various applications, including biosensors, photonic-integrated circuits, or quantum optics experiments. Yet, despite the convenience of fabricating wafer-scale integrated microresonators with moderate Q values using standard microfabrication techniques, surface-tension-induced microcavities (STIMs), which have atomic-level surface roughness enabling the observation of Q values larger than 106, could only be produced using individual thermal treatment of every single microresonator within the devised area. Here, we demonstrate a facile method for large-scale fabrication of silica STIMs of various morphologies. Q values exceeding 106 are readily obtained using this technique. This study represents a significant advancement toward fabrication of wafer-scale optoelectronic circuitries.