New Physics: Sae Mulli

Aims and Scope

The origin of New Physics: Sae Mulli (NPSM, ISO abbreviation: New Phys.: Sae Mulli.): Sae Mulli (새물리 in Korean characters means ‘new physics’) is the oldest Korean pure scientific journal. It was first published in 1961 just after the Korean War by the Korean Physical Society (KPS). The primary mission of Sae Mulli was to start building up Korean physics research community from almost nothing and in fact Sae Mulli had made tremendous contributions to the Korean science community. Through a peer-review system, Sae Mulli had continued elevating the level of scientific researches, consequently becoming a cornerstone of the economic miracle of Korea...

Editor-in-Chief : Sunglae CHO
New Physics: Sae Mulli Editorial Board

pISSN : 0374-4914
eISSN : 2289-0041

Tel : +82-2-556-4737
Fax : +82-2-554-1643
E-mail: npsm@npsm-kps.org

Research Papers

A Phase Unwrapping Algorithm in Three-Wavelength Digital Holographic Microscopy

Sanghoon SHIN¹, Younghun YU*²

¹ Kanghae Precision System, Hwaseong 18487, Korea

² Department of Physics and Research Institute for Basic Sciences, Jeju National University, Jeju 63243, Korea

Multi-wavelength holography has a better axial range than single-wavelength holography, thus allowing unambiguous phase imaging. Noise amplification is the limiting factor in multi-wavelength holography as noise is amplified by a factor equivalent to the magnification of the wavelengths. Here, we propose a new algorithm to remove noise amplification in multi-wavelength holography. The proposed method does not use phase unwrapping and removes 2$\pi$ ambiguities. Experiments and numerical simulations indicated that the proposed method is fast, has low noise, and is useful for measuring samples with arbitrary step heights.

New Phys.: Sae Mulli 2018; 68: 1378-1383

Influences of the Composition on Spectroscopic Characteristics of Al$_x$Ga$_{1-x}$N Thin Films

Dae Jung KIM¹, Bong Jin KIM¹, Duk Hyeon KIM¹, Jong Won LEE*²

¹ School of Basic Sciences, Hanbat National University, Daejeon 34158, Korea

² Department of Advaned Materials Engineering, Hanbat National University, Daejeon 34158, Korea

In this study, Al$_x$Ga$_{1-x}$N films were grown on (0001) sapphire substrates by using metal-organic chemical vapor deposition (MOCVD). The crystallinity of the grown films was examined with X-ray diffraction (XRD) patterns. The surfaces and the chemical properties of the Al$_x$Ga$_{1-x}$N films were investigated using atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS), respectively. The optical properties of the Al$_x$Ga$_{1-x}$N film were studied in a wide photon energy range between 2.0 $\sim$ 8.7 eV by using spectroscopic ellipsometry (SE) at room temperature. The data obtained by using SE were analyzed to find the critical points of the pseudodielectric function spectra, <$\varepsilon(E)$> = <$\varepsilon_1(E)$> + $i$<$\varepsilon_2(E)$>. In addition, the second derivative spectra, $d^2$<$\varepsilon(E)$>/$dE^2$, of the pseudodielectric function for the Al$_x$Ga$_{1-x}$N films were numerically calculated to determine the critical points (CPs), such as the $E_0$, $E_1$, and $E_2$ structure. For the four samples ($x$ = 0.18, 0.21, 0.25, 0.29) between a composition of $x$ = 0.18 and $x$ = 0.29, changes in the critical points (blue-shifts) with increasing Al composition at 300 K for the Al$_x$Ga$_{1-x}$N film were observed via ellipsometric measurements for the first time.

New Phys.: Sae Mulli 2018; 68: 1281-1287

New Phys.: Sae Mulli 2018; 68: 1281~1388

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Research Papers

Influences of the Composition on Spectroscopic Characteristics of Al$_x$Ga$_{1-x}$N Thin Films

Dae Jung KIM, Bong Jin KIM, Duk Hyeon KIM, Jong Won LEE*

New Phys.: Sae Mulli 2018; 68: 1281-1287 https://doi.org/10.3938/NPSM.68.1281