光學顯微影像系統實驗室

實驗室連結:  http://optics.mc.ntu.edu.tw/zh_tw

光學顯微影像系統實驗室的主持人為 駱遠副教授,其專長領域包含3D光學顯微系統 ( 3D optical microscopic system )、超快內視鏡技術 ( High-speed optical endoscopy )、多焦聚光學全相鏡頭 ( Multi-focal volume holographic lenses )、非侵入式光學影像與設計 ( Non-invasive optical microscopy and design )、繞射光學造影 ( Diffraction optics )。

 

Multiplane Holographic Non-scanning microscopy:

 
Optical sectioning techniques offer the ability to acquire three-dimensional information from various organ tissues by discriminating between the desired in-focus and out-of-focus (background) signals. Alternative techniques to confocal, such as active structured illumination, exist for fast optically sectioned images, but they require individual axial planes to be imaged consecutively. In this article, an imaging technique (THIN), by utilizing active Talbot illumination in 3D and multiplexed holographic Bragg filters for depth discrimination, is demonstrated for imaging in vivo 3D biopsy without mechanical or optical axial scanning.
 


 

Phase-preserved macroscopic visible-light carpet cloaking beyond two dimensions:

 
Transformation optics, a recent geometrical design strategy of light manipulation with both ray trajectories and optical phase controlled simultaneously, promises without precedent an invisibility cloaking device that can render a macroscopic object invisible even to a scientific instrument measuring optical phase. However, previous macroscopic cloaks only demonstrated the recovery of ray trajectories after passing through the cloaks, while whether the optical phase would reveal their existence still remains unverified. In this paper, a phase- preserved macroscopic visible-light cloak is demonstrated in a geometrical construction beyond two dimensions. As an extension of previous two-dimensional (2D) macroscopic cloaks, this almost-three-dimensional cloak exhibits three-dimensional (3D) invisibility for illumination near its center (i.e. with a limited field of view), and its ideal wide-angle invisibility performance is preserved in multiple 2D planes intersecting in the 3D space. Optical path length is measured with a broadband pulsed-laser interferometer, which provides unique experimental evidence on the geometrical nature of transformation optics.
 
 

Nano-SiO2 in PQ-PMMA for Holographic Filters in Imaging:

Holographic filters in imaging/data storage/communications are required to have high Bragg selectivity, namely narrow angular and spectral bandwidth, to obtain spatial-spectral information within a three-dimensional object. The holographic filters with optimized ratio of nano-SiO2 in PQ-PMMA can significantly improve the performance of Bragg selectivity and diffraction efficiency by 53% and 16%, respectively.

  

Images at two depths within a grapefruit obtained using two multiplexed holographic nano-SiO2 PQ-PPMA filters.

 

Wavelength-Coded Holographic Microscopy:

A wavelength-coded multifocal microscope incorporates multiplexed and wavelength-coded holographic gratings to generate wavelength-selective multifocal planes. The focal planes are longitudinally spaced on the object plane, and each focal plane is probed by a designated wavelength. The recording of the multiplexed gratings takes place at a single wavelength by utilizing the Bragg degeneracy property; thus the maximum sensitive wavelength of blue 488 nm is used for recording, but the device is operated at a broad wavelength band of interest, all the way to red 633 nm. Figure on the left shows Two depth-resolved images of an onion obtained with wavelength-coded multifocal microscopy using both blue and red LEDs for illumination. Figure in the middle shows One of the two depth-resolved images obtained with wavelength-coded multifocal microscopy when the blue LED is on and red one is off.

 

Figure on the right shows One of the two depth-resolved images obtained with wavelength-coded multifocal microscopy when the red LED is on and blue one is off.

 

Spatial-Spectral Fluorescence Imaging:

A three-dimensional imaging system incorporating multiplexed holographic gratings is able to visualize fluorescence tissue structures. Holographic gratings formed in volume recording materials such as PQ-PMMA photopolymer have narrowband angular and spectral transmittance filtering properties which enable obtaining spatial-spectral information within an object. The imaging system’s ability is demonstrated to obtain multiple depth-resolved fluorescence images.

  

Figure on the left shows the experimental system setup, and figure on the right shows two depth-resolved images of a mouse colon.