Defocus severely reduces image sharpness in various optical microscopy techniques. Indeed, in wide-field methods, specimen-induced aberrations or thermal drifts of the microscope hardware can result in a walk-off between the focal plane of the detection objective and the sample. When imaging living specimens in a 3D environment, the sample itself may move along the optical axis, changing its fo...

Tomographic phase microscopy is a laser interferometry technique in which a 3D refractive index map of a biological sample is constructed from quantitative phase images collected at a set of illumination angles. Although the resulting tomographic images provide valuable information, their resolution declines at axial distances beyond about 1 microm from the focal plane. We describe an improved ...

A conventional camera has a limited depth of field (DOF), which often results in defocus blur and loss of image detail. The technique of image refocusing allows a user to interactively change the plane of focus and DOF of an image after it is captured. One way to achieve refocusing is to capture the entire light field. But this requires a significant compromise of spatial resolution. This is be...

Light field reconstruction from images captured by focal plane sweeping can achieve high lateral resolution comparable to the modern camera sensor. This is impossible for the conventional micro-lenslet-based light field capture systems. However, the severe defocus noise and the low depth resolution limit its applications. In this paper, we analyze the defocus noise in the focal-plane-sweeping-b...

We present a plane-scanning RESOLFT [reversible saturable/switchable optical (fluorescence) transitions] light-sheet (LS) nanoscope, which fundamentally overcomes the diffraction barrier in the axial direction via confinement of the fluorescent molecular state to a sheet of subdiffraction thickness around the focal plane. To this end, reversibly switchable fluorophores located right above and b...

The increase of array size and decrease of cell size make the testing of infrared focal plane array (FPA) being difficult. A design for test scheme, cross-check test, for infrared focal plane array (FPA) is presented in this paper. For an array size of M by N, the testing times can be reduced from the order of M*N to M+N. Analysis on the fault detectability of the proposed test scheme is also p...

Vortices of different charges are embedded in a wavefront that has quadratic phase variation, and the intensity distribution near the focal plane is studied. This method may be useful in realizing complicated beam profiles. We have experimentally demonstrated the generation of vortex arrays having integer as well as fractional topological charges that produce different intensity profiles at the...

An analog-to-digital converter for on-chip focal-plane image sensor applications. The analog-to-digital converter utilizes a single charge integrating amplifier in a charge balancing architecture to implement successive approximation analog-to-digital conversion. This design requires minimal chip area and has high speed and low power dissipation for operation in the 2-10 bit range. The inventio...