Polarization-Dependent Carrier Dynamics in Quantum-Dot Semiconductor Optical Amplifiers for All-Optical-Wavelength Converters

주형규,Jonggoo Lee,이승백 한국물리학회 2007 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.50 No.6

We examine ultrafast nonlinear birefringence of femtosecond optical pulses propagating through a semiconductor optical amplifier whose active element is composed of InAs/InP quantum dots at about 1.55 $\mu$m. The polarization-sensitive carrier dynamics in quantum dots are modeled for nonlinear gain bleaching that is employed for nonlinear birefringence for all-optical-wavelength converters. It is revealed that quantum dots support ultrafast nonlinear gain bleaching for ultrafast birefringence used in ultrafast all-optical-wavelength converters. The pump-pulse energy is one of the key ingredients for a well-shaped converted signal. In addition, nonlinear gain and index dynamics are discussed for ultra-high-speed operation with reduced pattern-effects.

광산업의 근간이 이루는 III-V반도체 기판제조를 위한 장치/장비 기술

주형규 대한전자공학회 2023 전자공학회지 Vol.50 No.1

농촌지역 고혈압 및 당뇨병 환자들의 치료순응도에 관한 연구

주형규,최진수 대한가정의학회 1994 Korean Journal of Family Medicine Vol.15 No.7

Group-velocity Dispersion Effects on Quantum Noise of a Fiber Optical Soliton in Phase Space

주형규,이은철 한국물리학회 2010 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.57 No.1

Group-velocity dispersion (GVD) effects on quantum noise of ultrashort pulsed light are theoretically investigated at the soliton energy level, using Gaussian-weighted pseudo-random distribution of phasors in phase space for the modeling of quantum noise properties including phase noise, photon number noise, and quantum noise shape in phase space. We present the effects of GVD that mixes the different spectral components in time, on the self-phase modulation(SPM)-induced quantum noise properties in phase space such as quadrature squeezing, photon-number noise, and tilting/distortion of quantum noise shape in phase space, for the soliton that propagates a distance of the nonlinear length ηNL = 1/(γP0) (P0 is the pulse peak power and is the SPM parameter). The propagation dependence of phase space quantum noise properties for an optical soliton is also provided.

Quantum Fluctuation of Ultrashort Pulsed Light in a Semiconductor Waveguide at Just Below Band-gap Energy

주형규,이은철 한국물리학회 2009 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.55 No.2

The quantum noise of 1-ps pulsed light is theoretically investigated in a semiconductor waveguide at just below the band-gap energy, where Kerr effects with n2 < 0 induce nonlinear negative-ω chirping, which is useful for alternative devices to a phase conjugator. Our calculation shows that Kerr effects with n2 < 0 squeeze quantum noise below the standard quantum limit (SQL), leading to a nonlinear increase in the phase-noise with increasing a pulse energy while keeping the whole photon-number noise of light constant, similar to the case with n2 > 0. However, this nonlinear negative-ω chirping produces a clockwise tilted ellipse of the quantum noise distribution for squeezed light in phase space, unlike the case with n2 > 0. In addition, we estimate that spatial modal area modification caused by self-defocusing with n2 < 0 results in a reduced degree of squeezing of light with diminished phase noise. The quantum noise of 1-ps pulsed light is theoretically investigated in a semiconductor waveguide at just below the band-gap energy, where Kerr effects with n2 < 0 induce nonlinear negative-ω chirping, which is useful for alternative devices to a phase conjugator. Our calculation shows that Kerr effects with n2 < 0 squeeze quantum noise below the standard quantum limit (SQL), leading to a nonlinear increase in the phase-noise with increasing a pulse energy while keeping the whole photon-number noise of light constant, similar to the case with n2 > 0. However, this nonlinear negative-ω chirping produces a clockwise tilted ellipse of the quantum noise distribution for squeezed light in phase space, unlike the case with n2 > 0. In addition, we estimate that spatial modal area modification caused by self-defocusing with n2 < 0 results in a reduced degree of squeezing of light with diminished phase noise.

배초향 종자처리가 발아성 향상에 미치는 영향

주형규,이정은,강점순 한국환경과학회 2021 한국환경과학회지 Vol.30 No.1

This study was carried out to establish optimal conditions for breaking dormancy of Agastache rugosa O. Kuntze seeds. A series of experiments according to seed maturity and treatment with plant growth regulators were performed to improve germination percentage and synchronize germination of the seeds. In addition, it was conducted to test whether the useful effect of seed treatment before sowing leads to healthy seedling and early vigorous growth. The average seed size was 1.85 mm (length) x 0.82 mm(width). The seed size was much smaller than other vegetable seeds. Seeds colorappeared dark brown, the shape of the seeds was oval and the weight of 1,000seeds was 352.8 mg. The optimum germination temperature was 22℃. Light exposure during germination did not affect germination promotion, suggesting that A. rugosa seeds are a kind of dark germinating seeds. Seed dormancy lasted for 40 days after harvesting, and GA3 treatment of dormant seeds could break dormancy. There were significant differences in germination percentage and rate according to the maturity of seeds. The germination percentage of mature seeds was 10 – 18% higher than that of immature seeds, and germination rate was 2 days faster. GA3 treatment during growth regulator treatment improved germinability, but BAP or ethephone treatment did not. The optimal growth regulator concentration of for germination was the combination treatment of 100 mM GA3 + 100 mM BAP.

Intra-Pulse Quantum Spectral Structure of Ultrafast Optical Pulses in a Self-Defocusing Semiconductor Waveguide

주형규,이승백,이종구 한국물리학회 2006 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.48 No.3

We investigate the intra-pulse quantum structure of an ultrafast optical pulse that propagates through an AlGaAs waveguide at the band-gap energy where nonlinear refraction is negative, i.e., the self-defocusing regime. In this regime, the sign of the group velocity dispersion parameter is positive to counteract the Kerr effects in frequency chirping. We show the evolution of the quantum spectral correlation with increasing pulse energy. A positive correlation between the two wings of the pulse spectrum is seen to occur as well as the spectral self-correlation, leading to a cross-shaped correlation structure in the quantum spectral correlation map. The pulse energy that supports the broadened spectra produces increased complexity in the correlation structure. Our calculation shows a spectral correlation map that is different from the fibre optical solitonic case due to the different nonlinear dynamics of interplay between the self-phase modulation and the group velocity dispersion for the quantum correlation structure.J?t

PZT 나노입자의 요변성을 이용한 박막제조

주형규 ( Hyung Gyu Joo ),전병세 ( Byung Sei Jun ) 경남대학교 신소재연구소 2011 신소재연구 Vol.23 No.-

Mechanism for Nitrogen-Originated Negative-Bias Temperature Instability in a MOSFET with a Si-Oxynitride Gate Dielectric

이은철,주형규 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.52 No.2

We propose an atomic model for N-related interface defects that are responsible for the enhanced negative-bias temperature instability (NBTI) in a Si-oxynitride p-PMOSFET through first-principles total energy calculations. Among them, the defects involving a N interstitial and two neighboring O interstitials at the Si/SiO₂ interface are dominant species stabilized in the hydrogenated states for nearly the whole range of stoichiometric conditions. The H atoms passivate the undercoordinated Si atoms and are possibly removed with energies of about 3.4 eV, similar to Si-H bond dissociations in Si. After the dissociations of the H atoms, the dominant defects have donor-like levels near the conduction-band edge and thus, are stabilized as a positive charge, successfully explaining the NBTI degradations in the threshold voltage and drive current. We propose an atomic model for N-related interface defects that are responsible for the enhanced negative-bias temperature instability (NBTI) in a Si-oxynitride p-PMOSFET through first-principles total energy calculations. Among them, the defects involving a N interstitial and two neighboring O interstitials at the Si/SiO₂ interface are dominant species stabilized in the hydrogenated states for nearly the whole range of stoichiometric conditions. The H atoms passivate the undercoordinated Si atoms and are possibly removed with energies of about 3.4 eV, similar to Si-H bond dissociations in Si. After the dissociations of the H atoms, the dominant defects have donor-like levels near the conduction-band edge and thus, are stabilized as a positive charge, successfully explaining the NBTI degradations in the threshold voltage and drive current.

405 nm 피코초 펄스 레이저로 여기 된 인디고 카민(indigo carmine) 염료의초고속 3차 비선형 광학 특성 연구

홍진혁,주형규 한국물리학회 2023 새물리 Vol.73 No.2

Through Z-scan techniques with a 100 pico-second optical pulsed light source, we studied the ultrafast third-order optical nonlinearity of indigo carmine at 405 nm, at which little linear absorption occurred. Nonlinear absorption measurement demonstrated the optical power limiting capability of indigo carmine, which is attributable to the occurrence of a two-photon absorption-like process, while the nonlinear refraction response produced self-defocusing features arising from negative optical nonlinearity. Although the magnitudes for the nonlinear absorption and refraction of indigo carmine at 405 nm were smaller than those generated under a continuous wave light source at 633 nm, at which significant linear absorption occurred, they turned out to be much greater than those of the nonlinear semiconductor materials reported in the literature. We experimentally explored the properties of the optical nonlinearity of indigo carmine at 405 nm and compared them with those at 633 nm. This work demonstrates the potential applications of indigo carmine for linear absorption-free optical power limiting capability at 405 nm, at which inorganic materials can hardly function as optical power limiters. 본 논문에서는 인디고 카민 염료의 초고속 3차 비선형 광학적 성질에 대한 연구를 다루기 위해 특히 선형 흡수가 약하게 일어나는 405 nm 파장대에서 100 피코초 레이저를 이용하여 Z-scan 테크닉을 수행하였다. 인디고 카민은 자가비포집의 특성을 보였으며 이는 음의 부호를 갖는 비선형 굴절 현상에 기인한다. 또한 인디고 카민은 405 nm 파장대에서 역 포화 흡수 형태의 비선형 흡수현상을 보였으며, 마치 3차 비선형 흡수현상인 이중 광자 흡수현상과 비슷한 특성을 보였다. 405 nm 파장대에서의 비선형 흡수/굴절 계수는 선형 흡수가 잘 일어나는 633 nm 파장대에서 보다 그 크기가 작은 것으로 보이지만, 비선형 무기 반도체의 비선형 흡수/굴절 계수들보다는 훨씬 큰 결과를 얻었다. 본 논문에서는 405 nm 파장대에서의 초고속 3차 비선형성에 대한 실험결과들을 633 nm 파장대에서의 기존 결과와 비교하여 논의할 것이다. 405 nm 파장대에서는 광 파워 제한기능을 보유하는 물질을 일반적으로 찾기 힘들지만, 인디고 카민의 경우에는 405 nm 파장대에서 선형 흡수에 의한 빛 에너지 감쇄없이 광 파워 제한자로서 기능을 수행할 수 있는 잠재성이 있음을 본 논문에서 확인할 수 있었다.