In conventional far-field optical microscopy, it has a limitation on spatial resolution due to diffraction barrier, known as Abbe’s diffraction limit. In detail, when light interacts with an object, interacted light generates near-field and far-field components. The far-field component is propagating light through space and used in conventional optical microscopy. The near-field component is nonpropagating light whose amplitude exponentially decays as it propagates. Because the near-field light includes high-spatial frequency components compared to the far-field light, it is a key parameter to overcome resolution limit in optical microscopy. In this thesis, we developed two different types of super-resolution microscopy. One is a near-field scanning optical microscopy (NSOM). NSOM can provide sub-diffraction resolution by directly detecting the near-field light using a metal coated tip with a small aperture. To obtain a super-resolution image from light-emitting diode (LED), a home-built NSOM system was combined with spectroscopy. By applying correlation analysis, LED samples were quantitatively analyzed in sub-diffraction scale. The other one is super-resolution optical fluctuation imaging (SOFI). SOFI enables to provide super-resolution images by estimating high-spatial frequency components in near-field light using statistical analysis such as correlation from temporal optical fluctuations of fluorophores referred to as blinking. However, because SOFI utilizes intrinsic blinking property of fluorophores, it is only applicable to specific types of fluorophore. To overcome this limitation, we developed a new method by combining SOFI with speckle pattern illumination (S-SOFI). Because S-SOFI uses controllable optical fluctuation induced by illumination, it is applicable for any types of fluorophores. Applying S-SOFI, we theoretically and experimentally demonstrated its ability of super-resolution imaging. Furthermore, S-SOFI was combined with near-field speckle pattern (NS-SOFI) to further improve the resolution of S-SOFI. Using NS-SOFI, we experimentally obtained an image with improved resolution compared to S-SOFI.
빛은 물체와 상호작용 할 때, 진행하는 빛인 원접장과 진행하지 않고 표면에서 급격히 감쇠하는 빛인 근접장으로 나뉘게 된다. 광학 현미경은 이때 생성된 빛 중 원접장만을 이용하기 때문에 해상도의 한계를 가진다. 본 학위논문에서는 근접장과 상관관계 분석을 이용하여 두 종류의 고해상도 현미경을 개발하고 이를 실제 적용하여 응용했다. 첫번째로는 금속 팁을 이용하여 근접장을 직접적으로 추출함으로써 고분해능 이미지를 구현하는 근접장 현미경이다. 이를 직접 개발하고 상관관계 분석과 결합하여 발광소자에 적용함으로써 고해상도의 스케일에서 광특성을 분석했다. 다른 방법으로는 깜빡임이라 불리우는 형광체의 광학적 요동을 이용하여 간접적으로 고주파수 성분을 뽑아내는 방법이다. 본 연구에서는 형광체의 깜빡임 현상 대신에 반점조명을 입사빔으로 적용하여 방법을 확장하였고 이론적, 실험적 접근을 통해 고해상도 이미징이 가능함을 보였다. 또한 근접장 반점조명을 적용하여 향상된 고해상도 이미징을 구현했다.
