Selection of stimulated Raman scattering signal by entangled photons

Munkhbaatar, Purevdorj,Myung-Whun, Kim Elsevier 2017 OPTICS COMMUNICATIONS - Vol.383 No.-

<P><B>Abstract</B></P> <P>We propose an excitation-probe measurement method utilizing entangled photon pulses. The excitation-probe signal is dominated by stimulated Raman scattering as well as two-photon absorption when the time delay between the excitation pulse and the probe pulse is shorter than the pulse duration. We demonstrate that the two-photon-absorption signal can be suppressed when the photons of the pulses are entangled. The stimulated Raman scattering signal can be composed of many peaks distributed over broad photon energies owing to the transitions between numerous quantum states in complex materials. We show that the desired peaks among the many peaks can be selected by controlling the thickness of the nonlinear crystal, the pump pulse center frequency, and the polarization of the excitation pulse and probe pulse.</P> <P><B>Highlights</B></P> <P> <UL> <LI> We propose an excitation-probe measurement method utilizing entangled photon pulses. </LI> <LI> The excitation-probe signal is dominated by nonlinear processes including stimulated Raman scattering. </LI> <LI> We demonstrate that the stimulated Raman scattering signal can be relatively enhanced by the entangled photons. </LI> <LI> The stimulated Raman scattering signal si composed of many peaks distributed over broad photon energies. </LI> <LI> Only the desired peaks among those many peaks can be selected by controlling the thickness of the nonlinear crystal. </LI> </UL> </P>

COMPUTATIONAL EFFICIENCY OF A MODIFIED SCATTERING KERNEL FOR FULL-COUPLED PHOTON-ELECTRON TRANSPORT PARALLEL COMPUTING WITH UNSTRUCTURED TETRAHEDRAL MESHES

Kim, Jong Woon,Hong, Ser Gi,Lee, Young-Ouk Korean Nuclear Society 2014 Nuclear Engineering and Technology Vol.46 No.2

Scattering source calculations using conventional spherical harmonic expansion may require lots of computation time to treat full-coupled three-dimensional photon-electron transport in a highly anisotropic scattering medium where their scattering cross sections should be expanded with very high order (e.g., $P_7$ or higher) Legendre expansions. In this paper, we introduce a modified scattering kernel approach to avoid the unnecessarily repeated calculations involved with the scattering source calculation, and used it with parallel computing to effectively reduce the computation time. Its computational efficiency was tested for three-dimensional full-coupled photon-electron transport problems using our computer program which solves the multi-group discrete ordinates transport equation by using the discontinuous finite element method with unstructured tetrahedral meshes for complicated geometrical problems. The numerical tests show that we can improve speed up to 17~42 times for the elapsed time per iteration using the modified scattering kernel, not only in the single CPU calculation but also in the parallel computing with several CPUs.

Computational Efficiency of a Modified Scattering Kernel for Full-Coupled Photon-Electron Transport Parallel Computing with Unstructured Tetrahedral Meshes

김종운,홍서기,이영욱 한국원자력학회 2014 Nuclear Engineering and Technology Vol.46 No.2

Scattering source calculations using conventional spherical harmonic expansion may require lots of computation time totreat full-coupled three-dimensional photon-electron transport in a highly anisotropic scattering medium where their scatteringcross sections should be expanded with very high order (e.g., P7 or higher) Legendre expansions. In this paper, we introduce a modified scattering kernel approach to avoid the unnecessarily repeated calculations involvedwith the scattering source calculation, and used it with parallel computing to effectively reduce the computation time. Itscomputational efficiency was tested for three-dimensional full-coupled photon-electron transport problems using our computerprogram which solves the multi-group discrete ordinates transport equation by using the discontinuous finite element methodwith unstructured tetrahedral meshes for complicated geometrical problems. The numerical tests show that we can improvespeed up to 17~42 times for the elapsed time per iteration using the modified scattering kernel, not only in the single CPUcalculation but also in the parallel computing with several CPUs.

Light Scattering Amplification on Dye Sensitized Solar Cells Assembled by Hollyhock-shaped CdS-TiO2 Composites

Gayoung Lee,Huryul Lee,엄명헌,강미숙 대한화학회 2012 Bulletin of the Korean Chemical Society Vol.33 No.9

To investigate the scattering layer effect of a TiO2 multilayer in dye-sensitized solar cells (DSSCs), we designed a new DSSC system, assembled with a CdS-TiO2 scattering layer electrode. A high-magnification SEM image exhibited hollyhock-like particles with a width of 1.5-2.0 μm that were aggregated into 10-nm clumps in a hexagonal petal shape. The efficiency was higher in the DSSC assembled with a CdS-TiO2 scattering layer than in the DSSC assembled with TiO2-only layers, due to the decreased resistance in electrochemical impedance spectroscopy (EIS). The short-circuit current density (Jsc) was increased by approximately 7.26% and the open-circuit voltage (Voc) by 2.44% over the 1.0 wt % CdS-TiO2 composite scattering layer and the incident photon-to-current conversion efficiency (IPCE) in the maximum peak was also enhanced by about 5.0%, compared to the DSSC assembled without the CdS-TiO2 scattering layer.

Light Scattering Amplification on Dye Sensitized Solar Cells Assembled by Hollyhock-shaped CdS-TiO₂ Composites

Lee, Ga-Young,Lee, Hu-Ryul,Um, Myeong-Heon,Kang, Mi-Sook Korean Chemical Society 2012 Bulletin of the Korean Chemical Society Vol.33 No.9

To investigate the scattering layer effect of a $TiO_2$ multilayer in dye-sensitized solar cells (DSSCs), we designed a new DSSC system, assembled with a CdS-$TiO_2$ scattering layer electrode. A high-magnification SEM image exhibited hollyhock-like particles with a width of 1.5-2.0 ${\mu}m$ that were aggregated into 10-nm clumps in a hexagonal petal shape. The efficiency was higher in the DSSC assembled with a CdS-$TiO_2$ scattering layer than in the DSSC assembled with $TiO_2$-only layers, due to the decreased resistance in electrochemical impedance spectroscopy (EIS). The short-circuit current density ($J_{sc}$) was increased by approximately 7.26% and the open-circuit voltage ($V_{oc}$) by 2.44% over the 1.0 wt % CdS-$TiO_2$ composite scattering layer and the incident photon-to-current conversion efficiency (IPCE) in the maximum peak was also enhanced by about 5.0%, compared to the DSSC assembled without the CdS-$TiO_2$scattering layer.

생체 내 심부조직 이미징을 위한 고속 이광자 현미경 개발

이병학(Byunghak Lee),정보수(Bosu Jeong),남효석(Hyo Seock Nam),윤상준(Sang June Yoon),김기현(Ki Hean Kim) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.11

We have developed two-photon microscope which is optimized for in-vivo deep tissue imaging. We have developed two-photon microscope which is optimized for in-vivo deep tissue imaging. This system was characterized by signal decay and PSF measurement. Axial resolution of this system increases with increasing depth. And light scattering by tissue limits the imaging depth of two-photon microscope. Using commercial microscope body cannot detect all of emission light through the objective lens. So, we are upgrading two-photon microscope for detecting all of fluorescence signals which are ballistic and scattered. This new system provides deeper and better for in-vivo deep tissue imaging.

Optimization of hierarchical light-scattering layers in TiO₂ photoelectrodes of dye-sensitized solar cells

Nath, N.C.D.,Jung, I.S.,Kim, S.W.,Lee, J.J. Association for Applied Solar Energy ; Elsevier Sc 2016 SOLAR ENERGY -PHOENIX ARIZONA THEN NEW YORK- Vol.134 No.-

In this report, we demonstrate a novel approach of introducing hierarchically arranged light-scattering layers (LSLs) into the TiO<SUB>2</SUB> photoelectrodes of dye-sensitized solar cells (DSSCs) to enhance the light-harvesting efficiency (LHE) in the visible region of light. The increase of LHE extended the photocurrent onset from higher wavelength in the incident photon-to-current conversion efficiency (IPCE) spectra of the DSSCs with LSLs. Further, the LHE of the TiO<SUB>2</SUB> photoelectrode was maximized when the LSLs were hierarchically arranged in the regular TiO<SUB>2</SUB> photoelectrodes. The optimized hierarchical LSLs enhanced the optical density inside the film by the effect of producing higher wavelength light gradually with an increase in scattering particle size. The IPCE of the cells was increased up to ca. 35% for wavelengths ranging from 550 to 800nm as compared with cells without LSLs, which contributed to the enhancement of the PCE of the DSSCs from 7.08% to 9.37% with ca. 32% improvement over cells without scattering layers.

Combined Analysis of η Meson Hadro- and Photo-production off Nucleons

K. Nakayama,오용석,H. Haberzettl 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.2

The η-meson production in photon- and hadron-induced reactions, namely, γp → pη, π^−p → nη, pp → ppη, and pn ∪ pnη, are investigated in a combined analysis in order to learn about the relevant production mechanisms and the possible role of nucleon resonances in these reactions. We consider the nucleonic, mesonic, and nucleon resonance currents constructed within an effective Lagrangian approach and compare the results with the available data for cross sections and spin asymmetries for these reactions. We found that the reaction γp → pη could be described well with the inclusion of the well-established S_(11)(1535), S_(11)(1650), D_(13)(1520), and D_(13)(1700) resonances, in addition to the mesonic current. Consideration of other well-established resonances in the same mass region, including the spin-5/2 resonances, D_(15)(1675) and F_(15)(1680), does not further improve the results qualitatively. For the reaction π_−p → nη, the P_(13)(1720) resonance is found to be important for reproducing the structure observed in the differential cross section data. Our model also improves the description of the reaction NN → NNη to a large extent compared to the earlier results by Nakayama et al. [Phys. Rev. C 68, 045201 (2003)]. For this reaction, we address two cases where either the S_(11)(1535) or the D_(13) dominates. Further improvement in the description of these reactions and the difficulty to uniquely determine the nucleon resonance parameters in the present type of analysis are discussed.

이산화탄소 원격 계측을 위한 광 계수 방식의 라만 라이다 장치 개발

박선호,최인영,윤문상 한국광학회 2024 한국광학회지 Vol.35 No.2

이산화탄소 원격 계측을 위한 라만 라이다 장치를 개발하기 위해 라만 라이다 장치의 소형화를 진행하고, 이에 스캐닝 장치를 결합하여 라만 라이다 시스템을 개발하였다. 개발한 시스템의 성능 검증을 위하여 가스 챔버를 약 87 m 거리에 위치시킨 후, 이산화탄소의 농도 변화에 따른라만 산란 신호를 계측하였다. 그 결과 개발된 라만 라이다 장치를 이용하였을 때 약 0.67–40 vol%의 사이의 농도에서 높은 선형성을 나타냄을 확인하였다. This research is about the development of a Raman Lidar system for remote measurement of carbon dioxide present in atmospheric space. An aircooled laser with 355-nm wavelength and a 6-inch optical receiver were used to miniaturize the Raman Lidar system, and a scanning Raman Lidar system was developed using a two-axis scanning device and a light counter. To verify the performance of the developed Raman Lidar system, a gas chamber capable of maintaining a concentration was located at a distance of about 87 m, and the change in Raman signal according to the change inthe concentration of carbon dioxide was measured. As a result, it was confirmed that the change in the Raman-scattering signal of carbon dioxide, that appeared for a change in carbon dioxide concentration from about 0.67 to 40 vol% was linear, and the coefficient of determination (R 2 ) value, which indicates the correlation between carbon-dioxide concentration and Raman-scattering signal, showed a high linearity of 0.9999.

EQUIVALENT DOSE FROM SECONDARY NEUTRONS AND SCATTER PHOTONS IN ADVANCE RADIATION THERAPY TECHNIQUES WITH 15 MV PHOTON BEAMS

Ayuthaya, Isra Israngkul Na,Suriyapee, Sivalee,Pengvanich, Phongpheath The Korean Association for Radiation Protection 2015 방사선방어학회지 Vol.40 No.3

The scatter photons and photoneutrons from high energy photon beams (more than 10 MV) will increase the undesired dose to the patient and the staff working in linear accelerator room. This undesired dose which is found at out-of-field area can increase the probability of secondary malignancy. The purpose of this study is to determine the equivalent dose of scatter photons and neutrons generated by 3 different treatment techniques: 3D-conformal, intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT). The measurement was performed using two types of the optically stimulation luminescence detectors (OSL and OSLN) in the Alderson Rando phantom that was irradiated by 3 different treatment techniques following the actual prostate cancer treatment plans. The scatter photon and neutron equivalent dose were compared among the 3 treatments techniques at the surface in the out-of-field area and the critical organs. Maximum equivalent dose of scatter photons and neutrons was found when using the IMRT technique. The scatter neutrons showed average equivalent doses of 0.26, 0.63 and $0.31mSv{\cdot}Gy^{-1}$ at abdominal surface region which was 20 cm from isocenter for 3D, IMRT and VMAT, respectively. The scattered photons equivalent doses were 6.94, 10.17 and $6.56mSv{\cdot}Gy^{-1}$ for 3D, IMRT and VMAT, respectively. For the 5 organ dose measurements, the scattered neutron and photon equivalent doses in out of field from the IMRT plan were highest. The result revealed that the scatter equivalent doses for neutron and photon were higher for IMRT. So the suitable treatment techniques should be selected to benefit the patient and the treatment room staff.