Chapter Atomic Force Microscopy in Optical Imaging and Characterization

Urology & urogenital medicin

Fourier Factorization in the Plane Wave Expansion Method in Modeling Photonic Crystals

Biotechnolog

Atomic Force Microscopy in Optical Imaging and Characterization

Urology & urogenital medicin

Principal spectra describing magnetooptic permittivity tensor in cubic crystals

We provide unified phenomenological description of magnetooptic effects being linear and quadratic in magnetization. The description is based on few principal spectra, describing elements of permittivity tensor up to the second order in magnetization. Each permittivity tensor element for any magnetization direction and any sample surface orientation is simply determined by weighted summation of the principal spectra, where weights are given by crystallographic and magnetization orientations. The number of principal spectra depends on the symmetry of the crystal. In cubic crystals owning point symmetry we need only four principal spectra. Here, the principal spectra are expressed by ab-initio calculations for bcc Fe, fcc Co and fcc Ni in optical range as well as in hard and soft x-ray energy range, i.e. at the 2p- and 3p-edges. We also express principal spectra analytically using modified Kubo formula

Advances in Optical and Magnetooptical Scatterometry of Periodically Ordered Nanostructured Arrays

We review recent advances in optical and magnetooptical (MO) scatterometry applied to periodically ordered nanostructures such as periodically patterned lines, wires, dots, or holes. The techniques are based on spectroscopic ellipsometry (SE), either in the basic or generalized modes, Mueller matrix polarimetry, and MO spectroscopy mainly based on MO Kerr effect measurements. We briefly present experimental setups, commonly used theoretical approaches, and experimental results obtained by SE and MO spectroscopic analyses of various samples. The reviewed analyses are mainly related to monitoring optical critical dimensions such as the widths, depths, and periods of the patterned elements, their real shapes, and their line edge or linewidth roughness. We also discuss the advantages and disadvantages of the optical spectroscopic techniques compared to direct monitoring techniques

Magnetic properties of cobalt ultrathin film structures controlled by buffer layer roughness

Growth optimization of multilayers is a topic of interest due to their unique physical properties. Systems containing magnetic materials, such as platinum-cobalt, have been studied because of their potential for technological applications, e.g. spintronics, magnetic storage and magnetic sensors. Since the magnetic properties of thin layers are strongly related to the growth parameters, the fine tuning of these parameters is necessary to produce multilayers with specific properties required in various applications. Here, an efficient approach to tune the coercive field of Co ultrathin films in the multilayer by varying the underlayer thickness is demonstrated. Using magnetron sputtering, we prepared multilayer systems of Au(x)/Pt(5nm)/Co(0.7nm)/Au(5nm) with various thicknesses of Au underlayer. The surface morphology of Au(x)/Pt(5nm) stack on which Co layer was deposited was studied by atomic force microscopy. We show the possibility to control the interfacial roughness by changing the Au underlayer thickness due to its island-like growth mechanism (Volmer-Weber mode). As the nominal thickness of Au increases, the islands grow in larger lateral size, resulting in a higher overall roughness of the layer surface. Magnetization measurements indicate a direct influence of the underlayer roughness on the coercivity of the multilayers by promoting additional magnetic anisotropy. With thickness of the Au layer up to 20 nm, we can change the coercive field in the range from ~200 Oe to ~1100 Oe, while remaining a nearly constant saturation magnetization. The use of Cu replacing Au underlayer in the same multilayers was also investigated, demonstrating the possibility of coercivity adjustment using different materials. The results are important for applications where the magnetic properties of multilayer structures based on Co thin films could be adjusted via buffer layer roughness engineering.Comment: 15 pages, 8 figure

Optical and magneto-optical behavior of Cerium Yttrium Iron Garnet thin films at wavelengths of 200–1770 nm

Magneto-optical cerium-substituted yttrium iron garnet (Ce:YIG) thin films display Faraday and Kerr rotation (rotation of light polarisation upon transmission and reflection, respectively) as well as a nonreciprocal phase shift due to their non-zero off-diagonal permittivity tensor elements, and also possess low optical absorption in the near-infrared. These properties make Ce:YIG useful in providing nonreciprocal light propagation in integrated photonic circuits, which is essential for accomplishing energy-efficient photonic computation and data transport architectures. In this study, 80 nm-thick Ce:YIG films were grown on Gadolinium Gallium Garnet substrates with (100), (110) and (111) orientations using pulsed laser deposition. The films had bulk-like structural and magnetic quality. Faraday and Kerr spectroscopies along with spectroscopic ellipsometry were used to deduce the complete permittivity tensor of the films in the ultraviolet, visible and near-infrared spectral region, and the magneto-optical figure of merit as a function of wavelength was determined. The samples showed the highest IR Faraday rotation reported for thin films of Ce:YIG, which indicates the importance of this material in development of nonreciprocal photonic devices.National Science Foundation (U.S.)Semiconductor Research Corporation. Function Accelerated nanoMaterial Engineerin

Kelainan Peak Expiratory Flow Rate Dibandingkan dengan Keluhan Sistim Pernapasan – studi pada 75 anggota pasukan kuning, Surabaya

Telah dilakukan kajian untuk membandingkan hasil pemeriksaan faal paru Peak Expiratory Flow Rate (PEFR) dalam mendeteksi kelainan paru obstruktif dengan anamnesis adanya keluhan batuk, pengeluaran dahak, sesak nafas dan nafas berbunyi. Sebagai subyek penelitian adalah anggota pasukan kuning Kotamadya Surabaya yang bertugas di jalan raya sebanyak 75 orang. Dipilih anggota pasukan kuning karena dalam melaksanakan tugas sehari-hari diduga mendapat pemaparan polusi debu dan gas buang kendaraan bermotor. Hasil yang didapat adalah proporsi kelainan PEFR secara keseluruhan sebesar 42,67%, di antara yang mengeluh keluhan batuk sebesar 24,00%, di antara yang mengeluarkan dahak sebesar 14,67%, di antara yang sesak nafas sebesar 22,67% dan di antara yang nafasnya berbunyi sebesar 10,67%. Ternyata didapatkan hubungan antara kelainan faal paru PEFR dengan adanya keluhan batuk (p = 0,0216), dengan keluhan pengeluaran dahak (p = 0,0005), dengan keluhan sesak nafas (p = 0,018) dan dengan keluhan nafas berbunyi (p = 0,0000). Subyek dengan kelainan faal paru PEFR tanpa keluhan berkisar antara 30,67 –36% dari seluruh subyek yang diperiksa

Fourier factorization with complex polarization bases in the plane-wave expansion method applied to two-dimensional photonic crystals

We demonstrate an enhancement of the plane wave expansion method treating two-dimensional photonic crystals by applying Fourier factorization with generally elliptic polarization bases. By studying three examples of periodically arranged cylindrical elements, we compare our approach to the classical Ho method in which the permittivity function is simply expanded without changing coordinates, and to the normal vector method using a normal-tangential polarization transform. The compared calculations clearly show that our approach yields the best convergence properties owing to the complete continuity of our distribution of polarization bases. The presented methodology enables us to study more general systems such as periodic elements with an arbitrary cross-section or devices such as photonic crystal waveguides