摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
Holographic methods for recording fast movies whose speed is limited by the laser pulse duration if the recording material has sufficient sensitivity to reliably record a frame of the fast event with a single pulse. The method we describe uses the selectivity of multiplexed holograms to resolve frames that are recorded with adjacent pulses. Specially designed pulse generators are used to generate the signal and reference pulse trains. We experimentally demonstrate the system by making movies of laser induced shock waves with a temporal resolution of 5.9 ns, limited by the pulse width of the Q-switched Nd:YAG laser used in the experiments.