The Penn State Research Foundation

Peking University

Kebin Shi

Zhiwen Liu

Chuan Yang

Demetri Psaltis

Shizhuo Yin

Siyang Zheng

Perry S Edwards

Mingda Zhou

Peng Xi

Wentao Yu

Qian Xu

Qihuang Gong

A stimulated-emission-depletion (STED) super-resolution microscope includes an excitation light source, a depletion light source, an excitation light expanded beam alignment system, a spiral-shaped phase plate, a Bessel beam generating system, a depletion light focus lens, a beam combination system, an objective lens, a piezoelectric scanning system, a filter, a signal collection system, and a single-photon detector. The depletion light can be a first-order Bessel beam. The depletion light has anti-scattering and self-healing characteristics, and is capable of keeping the spot shape at a deeper position of a sample, thereby improving image resolution in the deep region of the sample. Compared to conventional STED super resolution microscope of deep-layer imaging using an adjustable correction collar, the present invention is simpler in experimental operations and does not require active adjustments. Compared to adaptive optical systems, the present experimental apparatus is simpler and less expensive.

STED super-resolution microscope and adjusting method based on a first-order Bessel beam

We present a method for parallel axial imaging, or z-microscopy, utilizing an array of tilted micro mirrors arranged along the axial direction. Image signals emitted from different axial positions can be orthogonally reflected by the corresponding micro mirrors and spatially separated for parallel detection, essentially converting the more challenging axial imaging to a lateral imaging problem. Each micro mirror also provides optical sectioning capability due to its finite dimension.

Z-microscopy

Embodiments of the invention provide a device called a 'G-Fresnel' device that performs the functions of both a linear grating and a Fresnel lens. We have fabricated the G-Fresnel device by using PDMS based soft lithography. Three-dimensional surface profilometry has been performed to examine the device quality. We have also conducted optical characterizations to confirm its dual focusing and dispersing properties. The G-Fresnel device can be useful for the development of miniature optical spectrometers as well as emerging optofluidic applications. Embodiments of compact spectrometers using diffractive optical elements are also provided. Theoretical simulation shows that a spectral resolution of approximately 1 nm can be potentially achieved with a millimeter-sized G-Fresnel. A proof-of-concept G-Fresnel-based spectrometer with subnanometer spectral resolution is experimentally demonstrated.

Compact spectrometer including a diffractive optical element with dual dispersion and focusing functionality

Apparatus and methods of four wave mixing (FWM) holography are described, including illuminating a sample with a first beam, a second beam, and a third beam, and combining the generated FWM signal with a reference beam at a imaging device to obtain holographic image data. In some examples, the first and second beams may be provided by a single pump-probe beam. The third beam may be a Stokes beam or an anti-Stokes beam. A representative example is coherent anti-Stokes Raman holography (CARS holography), which includes illuminating a sample with a pump/probe beam and a Stokes beam to obtain a CARS signal from the sample; and combining the CARS signal with a reference beam to obtain a CARS hologram.

Coherent anti-Stokes Raman holography

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Beijing, China

Kebin Shi