Optical phonons in TlGaS2

Khalafov, Z.D.
Hasanlı, Nızamı
Sardaly, P.M.


Optical absorption and reflection studies of Tl4InGa3S8 layered single crystals
Goksen, K.; Hasanlı, Nızamı; Ozkan, H. (Institute of Physics, Polish Academy of Sciences, 2007-07-01)
The optical properties of Tl4InGa3S8 layered single crystals have been studied by means of transmission and reflection measurements in the wavelength region between 400 and 1100 nm. The analysis of the room temperature absorption data revealed the presence of both optical indirect and direct transitions with band gap energies of 2.40 and 2.61 eV, respectively. Transmission measurements carried out in the temperature range of 10-300 K revealed the rate of change of the indirect band gap with temperature as g...
Optical properties of TlGa(SxSe1-x) 2 layered mixed crystals (0=x=1): Absorption edge and photoluminescence study at T=10 K
Hasanlı, Nızamı (Springer Science and Business Media LLC, 2018-09-01)
Transmittance measurements of layered mixed crystals were performed in the 1.80-2.80 eV photon energy range at . Band-gap energies of the studied crystals were estimated by means of the derivative spectra of transmittance and photon energy dependence of absorption coefficient. The compositional dependence of direct band-gap energy at revealed that as sulphur (selenium) composition is increased (decreased) in the mixed crystals, the direct band-gap energy increases from 2.19 eV () to 2.67 eV (). Photolumines...
Broadband spectral splitting of white light via 2D diffractive optical elements
Başay, Yalın; Yüce, Emre (The Scientific and Technological Research Council of Turkey, 2018-10-01)
An effective way of increasing the efficiency of solar cells is to spectrally split sunlight into several frequencies and absorb each frequency using appropriate photovoltaic materials. In this study, we establish a method to show spectral splitting of broadband solar light via iteratively optimized diffractive optical elements. We develop an algorithm in order to calculate 2D holographic patterns that focus two different frequencies to designated positions.
BILIKMEN, S; OMAR, A (Springer Science and Business Media LLC, 1994-05-01)
The Hamiltonian for an electron travelling through a large-amplitude backward electromagnetic wave, an axial guide magnetic field and radiation field is formulated. Poincare surface-of-section plots show that this Hamiltonian is non-integrable, and leads to chaotic trajectories. Equilibrium conditions are derived in the limit where the radiation field approaches zero. Compared to conventional FEL, the total energy of the system at pondermotive resonance E(c) is large, while the electron's critical energy...
Nonlinear frequency conversion of light inside a microcavity
Yüce, Emre (The Scientific and Technological Research Council of Turkey, 2019-01-01)
Changing the color of light in a small mode volume is essential for applications that require on-chip operation. Microcavities are profound structures given their property to confine light in a small mode volume. Here, I numerically investigate the frequency conversion of light in a microcavity and show that the frequency converted light intensity is distinguished from an open medium such as an optical fiber or a nonlinear crystal. I observe that the frequency converted light intensity increases with increa...
Citation Formats
Z. D. Khalafov, N. Hasanlı, and P. M. Sardaly, “Optical phonons in TlGaS2,” Soviet Physics Journal, pp. 271–273, 1977, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/36696.