초록 ▼

극초단 펄스형 광원의 제작:
- 적외선 cavity-dumped periodically poled lithium niobate optical parametric oscillator 개발
- 적외선부터 자외선까지 파장 가변이 가능한 Ti:sapphire amplifier/optical parametric amplifier 개발
측정 기술개발:
- 50 펨토초 미만의 시간분해능을 가지는 시간분해 형광 스펙트럼 측정기술 개발
- Diffractive beam splitter를 채용한 four wave mixin

극초단 펄스형 광원의 제작:
- 적외선 cavity-dumped periodically poled lithium niobate optical parametric oscillator 개발
- 적외선부터 자외선까지 파장 가변이 가능한 Ti:sapphire amplifier/optical parametric amplifier 개발
측정 기술개발:
- 50 펨토초 미만의 시간분해능을 가지는 시간분해 형광 스펙트럼 측정기술 개발
- Diffractive beam splitter를 채용한 four wave mixing을 이용하여 SRFWM, tau-resolved transient grating(TRTG) 테크닉 개발
광전자 물질 연구:
- Photochromic diarylethene의 반응 동역학 연구를 통한 효율적인 물질 개발에 기여
- 포르피린 어레이의 에너지 전달 규명
- 2-aminopurine을 이용하여 DNA 전하전달 규명
- Excited state intramolecular proton transfer 분자동력학 연구
- ZnO 반도체 나노막대의 exciton 동력학 및 나노막대의 길이에 따른 광특성 연구
- 물질 합성그룹과 공동 연구를 통한 광전자 물질 개발

Abstract ▼

Organic photoelectric materials have been studied extensively in an effort to develop devices to be used in communication, optical memory, display, and sensors. Photophysical properties of the material, especially their dynamical properties are important for the applications. To study dynamical phot

Organic photoelectric materials have been studied extensively in an effort to develop devices to be used in communication, optical memory, display, and sensors. Photophysical properties of the material, especially their dynamical properties are important for the applications. To study dynamical photophysical properties of organic photoelectric materials, we have developed widely tunable femtosecond light sources, state of the art measurement techniques. Using the techniques developed, we have studied photochromic reaction dynamics of diarylethene derivatives, energy transfer in porphyrin molecular systems with linear and circular arrangements, molecular reaction dynamics of the excited state proton transfer molecules, charge transfer in DNA, and exciton and relaxation dynamics in ZnO and CdSe based nanostructures.
Three types of light sources have been developed. First, cavity-dumped femtosecond optical parametric oscillator has been developed, which is tunable in the $1.0-1.5{\mu}m$ with pulse energy of 90 nJ, upto 3 MHz repetition rate, pulse stability noise less than 0.1%. This is the truly an ideal light source for time-resolved spectroscopy. Due to its high pealf intensity, efficient harmonic generation can be achieved to extend the wavelengths into UV region. Second, an 8-pass Ti:sapphire amplifier and optical parametric amplifier system has been designed and fabricated. Noncollinear parametric amplification leads to 30 femtosecond pulses tunable from infrared to visible. Third, cavity-dumped Ti:sapphire laser with power upto 100 nJ, repetiton rate upto 1 MHz has been developed. We have developed time-resolved fluorescence apparatus with <50 femtosecond time resolution, the fastest in the world. This setup is easy to operate and efficient to provide a powerful tool for the study of dynamic photophysical properties. The apparatus directly measures the time-frequency resolved spectra with 50 fs resolution, a level that cannot be achieved by any other group in the world. We have also developed time-frequency resolved measurement technique based on spectrally resolved four wave mixing technique, which was also developed in our group. This technique provides unprecedented $<5cm^{-1}$ precision in measurement of the peak position of a molecule in liquid.
Using the light sources and techniques developed, we have studied photochromic reaction dynamics of diarylethene photochromic molecules for the application in memory. Ring opening and closure reaction rates and dynamics have been measured by transient absorption and time-resolved fluorescence. The effect of substituent in 1,2-bis(2-methylbenzo(b)thiophen-3-yl) hexafluorocyclopentene (BTF6) has been studied to provide a design criteria for the development of efficient and robust photoelectric materials) Energy transfer in ponhyrin molecular systems with linear and circular arrangements has been studied. Both B and Q state are studied to reveal detailed relaxation channels of the energy Molecular reaction dynamics of the excited state proton transfer molecules has been studied. It was found that reactions in liquids, conformatioal heterogeneity is the critical factor. Charge transfer in DNA has been studied by uncorporating a fluorescenct probe 2-aminopurine in DNA. An ultrafast charge transfer was resolved for the first time. Exciton and relaxation dynamics in ZnO and CdSe based nanostructures have also been studied.

목차 Contents

• 표지...1
• 제출문...2
• 보고서 초록...3
• 요약문...4
• SUMMARY...7
• CONTENTS...9
• 목차...10
• 제 1 장 연구개발과제의 개요...11
• 1.1 서론...11
• 1.2 연구 개발의 목적 및 필요성...12
• 제 2 장 국내외 기술개발 현황...15
• 2.1. 기술개발 현황...15
• 2.2 연구결과의 위상 및 중요성...16
• 제 3 장 연구개발수행 내용 및 결과...17
• 3.1 이론적 실험적 연구 접근 방법...17
• 3.2 연구 내용 및 결과...19
• 3.2.1 펨토초 광원의 개발...19
• 3.2.1.1 Cavity-dumped Ti:sapphire laser...19
• 3.2.1.2 Cavity-dumped optical parametric oscillator...21
• 3.2.1.3 Multipass amplifier/optical parametric amplifier...23
• 3.2.2 시분해 측정 테크닉의 개발...25
• 3.2.2.1 Time-resolved fluorescence by upconversion...25
• 3.2.2.2 Diffractive beam splitter를 이용한 four wave mixing...29
• 3.2.3 물질 시스템 연구...31
• 3.2.3.1 Photochromic diarylethene 분자의 분자 반응 동역학...31
• 3.2.3.2 포르피린 분자의 에너지 전달...33
• 3.2.3.3 2-aminopurine을 이용한 DNA의 전하이동...36
• 3.2.3.4 ESIPT 분자 동역학...38
• 3.2.3.5 ZnO 반도체 나노막대의 광발광 연구...39
• 제 4 장 목표달성도 및 관련분야에의 기여도...40
• 4.1 목표 대비 달성도...40
• 4.2 기술 발전에의 기여도...41
• 제 5 장 연구개발결과의 활용계획...43
• 제 6 장 연구개발과정에서 수집한 해외 과학기술 정보...44
• 제 7 장 참고문헌...45