Hendradi Hardhienata

Single-Frequency Refractive Index Sensor Based on a Finite One-Dimensional Photonic Crystals with Two Defects

A numerical analysis by means of transfer matrix method has been performed on finite one-dimensional photonic crystals consisting of two-layer repeated cells and two non-identical defect cells for the normal incident transverse electric (TE) wave. The study reveals a remarkable new feature showing that the variation of a photonic pass-band transmittance can be induced by varying the refractive index of one of the defect layer at practically the same peak frequency, which offers the potential application for single frequency sensing. The result further demonstrates the flexibility of tailoring the system parameters for application in the desired range of refractive index at the required sensitivity. It is also shown that the photonic pass-band (PPB) peak transmittance is generally less than unity in the index range considered, except for the case with the grating segment lengths (M,N,L) satisfying the condition N=M+L. This peculiar feature is explained qualitatively in this work.

Bulk quadrupole and interface dipole contribution for second harmonic generation in Si(111)

The second harmonic generation (SHG) response was measured for arbitrarily oriented linear input polarization on Si(111) surfaces in rotational anisotropy experiments. We show for the first time, using the simplified bond hyperpolarizability model (SBHM), that the observed angular shifts of the nonlinear peaks and symmetry features—related to changes in the input polarization—help to identify the corresponding interface dipolar and bulk quadrupolar SHG sources, yielding excellent agreement with the experiment. Additionally, we evaluate for the s-in/p-out (sp) and p-in/p-out (pp)-polarization SHG intensities the contributions from the individual Si bonds. Furthermore, a relation between the four parameters arising from SBHM and six coefficients of the phenomenological SHG theory needed to reproduce experimental data is established.

Real-time optical sensor based on one dimensional photonic crystals with defects

A previous theoretical study of a finite one-dimensional photonic crystal composed of 12 unit cells with two defects had shown the existence of Photonic Pass Band (PPB) inside the Stop Band, which was suggested as a useful refractive index sensor due to the sensitive variation of PPB with respect to the change of refractive index of defect layer material. We report in this presentation our successful fabrication of a prototype of this system by means of electron beam evaporation equipment in a sample chamber at pressure of 10−3 Pa with BK-7 glass substrate at temperature 573 K. Each of the photonic cells is composed of a high index layer of OS-5 with refractive index of n =3D2.10, and an equal thickness low index layer of MgF2 with n =3D 1.38. In the first defect cell, the high index layer has twice the thickness of the other layers with the low index layer left unchanged, while in the second, defect cell is separated by 6 unit cells, and the first layer is void to be filled with the sample solution. The device was used for measuring the refractive index of sugar solution with concentration range of 20–500 g/L in the real time mode. The result was found to achieve determination coefficient more than 90%. Further measurement performed has demonstrated a result in good agreement with theoretical prediction reported previously.

The role of Kleinman Symmetry in the Simplified Bond Hyperpolarizability Model

We have shown previously in [J. Opt. Soc. Am. 31, 526-533 (2014)] that Kleinman symmetry plays an important role when comparing the third rank tensor associated with Second Harmonic Generation (SHG) obtained from the Simplified Bond Hyperpolarizability Model (SBHM) and from group theory (GT) for diamond and zincblende lattice. In this work we show that the third rank tensor derived from the SBHM has inherently the assumption of Kleinman symmetry.

Characteristics Of 1D Photonic Crystal Sensor With Two Defects

Numerical simulations of electromagnetic wave propagation inside a one‐dimensional (1D) photonic crystal with two defect rods are presented. The simulations were carried out by applying Finite Difference Time Domain (FDTD) method to solve the corresponding Maxwell equations. The result shows a linear dependence of time average energy density with respect to the variation of second defect refractive index, which can be potentially used for refractive index sensing platform. On the other hand, a non‐linear dependence of time average energy density is obtained by varying the radius of the second defect.

Bond Model of Second- and Third-Harmonic Generation in Body- and Face-Centered Crystal Structures

In this work, we describe the third- and fourth-rank tensors of body- and face-centered cubic systems and derive the s- and p-polarized SHG far field using the simplified bond-hyperpolarizability model. We also briefly discuss bulk nonlinear sources in such structures: quadrupole contribution, spatial dispersion, electric-field second-harmonic generation, and third-harmonic generation, deriving the corresponding fourth rank tensor. We show that all the third- and fourth-rank tensorial elements require only one independent fitting parameter.

Facet-dependent electric-field-induced second harmonic generation in silicon and zincblende

We discuss electric-field-induced second harmonic (EFISH) generation for silicon and zincblende facets (001), (011), and (111), employing the full fourth-rank tensor representation of the third-order susceptibility. Then we directly relate these 81 tensor elements with the contracted or Voigt matrix representation. Using group theory, we show that the number of independent elements is only two; however, at different facets, different linear combinations thereof appear. Also, specific expressions for the resulting s- and p-polarized second harmonic polarization are given for incident s- and p-polarizations, for the first time explaining the facet and angle of incidence dependence of EFISH. Finally, a classical oscillator model is used to explain the response of the electrons and the material combined with a direct physical interpretation of the breaking of the symmetry and thus the deformation of the electronic charge density along the bonds. Through this model we propose a connection between the strength parameter b for third harmonic generation and the second harmonic signal originated by EFISH mechanism.

Workshop and International Seminar on Science of Complex Natural Systems

The International Seminar on Science of Complex Natural Systems 2015 (ISS-CNS 2015 was organized by the Faculty of Mathematics and Natural Sciences, Bogor Agricultural University. This event aims at sharing knowledge and expertise, as well as building networks and collaborations among scientists from various institutions at a national and international level. ISS-CNS 2015 was organized as a scientific seminar, which covers a keynote speech, some invited talks, and some contributed presentations. The parallel presentations came from 67 papers, which were presented in the form of oral as well as poster presentations. These papers are contributed from scientists from various research and higher education institutions in Indonesia as well as some neighboring countries. In this occasion, we were honored to have our distinguished keynote speaker: Prof. Peter M. A. Sloot, Director of Complexity Institute (Nanyang Technological University, Singapore) and invited speakers: Prof. Stephane Douady (Universite Paris Diderot, France) Dr. Reed Beaman (University of Florida, USA) Dr. Ahmad Faqih (Bogor Agricultural University, Indonesia) Dr. Roby Muhamad (University of Indoensia, Indonesia)

Dynamics of Agent-Based Growing Network

In this work we describe the dynamics of growing network using an agent-based model. We restrict our analysis for the case of a closed spatial boundary and apply certain rules that must be followed by each agent. We show the emergence of an outbreak in the number of agents and connectivity degree before reaching a saturated state. Using the concept of Gibbs- Network entropy we show that the saturated connectivity entropy always converge to the same constant independent of the initial agent number and boundary dimension.

Transmission Characteristics of 1D Metallodielectric Photonic Crystal with a Defect Rod

In this paper we report the transmission characteristics of a 1D metallodielectric photonic crystal with a defect rod located in the middle of the structure. Simulations of the field propagation for the corresponding TE and TM modes were carried out using Finite Difference Time Domain (FDTD) technique on Maxwell’s Equation. The results show that for certain chosen parameters of the structure the field energy varies if the refractive index of the defect rod is changed and that approximate linier changes in time average energy density W exists for an refractive index range of 1.3–1.5 with a slight increase for TM case and a relatively steep decrease for TE case. The characteristics change due to variation of the defect rod radius is also considered.