Simultaneous direct holographic fabrication of photonic cavity and graded photonic lattice with dual periodicity, dual basis, and dual symmetry

Author(s):

D. Lowell and J. Lutkenhaus and D. George and U. Philipose and B. Chen and Y. Lin

Abstract:

“For the first time, to the authors’ best knowledge, this paper demonstrates the digital, holographic fabrication of graded, super-basis photonic lattices with dual periodicity, dual basis, and dual symmetry. Pixel-by-pixel phase engineering of the laser beam generates the highest resolution in a programmable spatial light modulator (SLM) for the direct imaging of graded photonic super-lattices. This technique grants flexibility in designing 2-D lattices with size-graded features, differing periodicities, and differing symmetries, as well as lattices having simultaneously two periodicities and two symmetries in high resolutions. By tuning the diffraction efficiency ratio from the SLM, photonic cavities can also be generated in the graded super-lattice simultaneously through a one-exposure process. A high quality factor of over 1.56 × 106 for a cavity mode in the graded photonic lattice with a large super-cell is predicted by simulations.”

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Publication: Optics Express

Issue/Year/DOI: Optics Express Vol. 25, Issue 13, pp. 14444-14452 (2017)

DOI: 10.1364/OE.25.014444

 

Miniature wide-spectrum mode sorter for vortex beams produced by 3D laser printing

Author(s):

Shlomi Lightman and Gilad Hurvitz and Raz Gvishi and Ady Arie

Abstract:

“Optical vortex beams can be used as carriers of information in optical communication and quantum optics applications. Owing to their spatial orthogonality, these beams can be multiplexed and demultiplexed, but up until now this was primarily achieved by bulky and large devices. In this work, a new approach is used to fabricate miniature vortex mode sorters based on three-dimensional laser printing, thereby enabling direct integration into optical systems. Mode sorters that are composed of two separate elements as well as a single integrated device are presented. These devices can handle both pure and mixed vortex beams with topological charge |𝑙|3 and |𝑙|2 for the dual-element device and integrated system, respectively. Mode-sorter spectral bandwidth and surface-quality effects are also discussed.”

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Publication: Optica

Issue/Year/DOI: Optica, Vol 4. , Issue 6, pp. 605- 610 (2018)
DOI: 10.1364/OPTICA.4.000605

Interferenceless coded aperture correlation holography–a new technique for recording incoherent digital holograms without two-wave interference

Author(s):

A. Vijayakumar and Joseph Rosen

Abstract:

“Recording digital holograms without wave interference simplifies the optical systems, increases their power efficiency and avoids complicated aligning procedures. We propose and demonstrate a new technique of digital hologram acquisition without two-wave interference. Incoherent light emitted from an object propagates through a random-like coded phase mask and recorded directly without interference by a digital camera. In the training stage of the system, a point spread hologram (PSH) is first recorded by modulating the light diffracted from a point object by the coded phase masks. At least two different masks should be used to record two different intensity distributions at all possible axial locations. The various recorded patterns at every axial location are superposed in the computer to obtain a complex valued PSH library cataloged to its axial location. Following the training stage, an object is placed within the axial boundaries of the PSH library and the light diffracted from the object is once again modulated by the same phase masks. The intensity patterns are recorded and superposed exactly as the PSH to yield a complex hologram of the object. The object information at any particular plane is reconstructed by a cross-correlation between the complex valued hologram and the appropriate element of the PSH library. The characteristics and the performance of the proposed system were compared with an equivalent regular imaging system.”

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Publication: Optics Express

Issue/Year/DOI: Optics Express Vol. 25, Issue 12, pp. 13883-13896 (2017)

DOI: 10.1364/OE.25.013883

 

White light wavefront control with a spatial light modulator

Author(s):

Dirk-Mathys Spangenberg and Angela Dudley and Pieter H. Neethling and Erich G. Rohwer and Andrew Forbes

Abstract:

“Spatial light modulators are ubiquitous tools for wavefront control and laser beam shaping but have traditionally been used with monochromatic sources due to the inherent wavelength dependence of the calibration process and subsequent phase manipulation. In this work we show that such devices can also be used to shape broadband sources without any wavelength dependence on the output beam’s phase. We outline the principle mathematically and then demonstrate it experimentally using a supercontinuum source to shape rotating white-light Bessel beams carrying orbital angular momentum.”

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Publication: Optics Express

Issue/Year/DOI: Optics Express, Vol. 22, Issue 11, (2014)
DOI: 10.1364/OE.22.013870

Coherent optical adaptive technique improves the spatial resolution of STED microscopy in thick samples

Author(s):

Wei Yan and Yanlong Yang and Yu Tan and Xun Chen and Yang Li and Junle Qu and Tong Ye

Abstract:

“Stimulated emission depletion (STED) microscopy is one of far-field optical microscopy techniques that can provide sub-diffraction spatial resolution. The spatial resolution of the STED microscopy is determined by the specially engineered beam profile of the depletion beam and its power. However, the beam profile of the depletion beam may be distorted due to aberrations of optical systems and inhomogeneity of a specimen’s optical properties, resulting in a compromised spatial resolution. The situation gets deteriorated when thick samples are imaged. In the worst case, the severe distortion of the depletion beam profile may cause complete loss of the super-resolution effect no matter how much depletion power is applied to specimens. Previously several adaptive optics approaches have been explored to compensate aberrations of systems and specimens. However, it is difficult to correct the complicated high-order optical aberrations of specimens. In this report, we demonstrate that the complicated distorted wavefront from a thick phantom sample can be measured by using the coherent optical adaptive technique. The full correction can effectively maintain and improve spatial resolution in imaging thick samples.”

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Publication: Photonics Research

Issue/Year/DOI: Photonics Research, Vol. 5, Issue3, pp. 176-181 (2017)
DOI: 10.1364/PRJ.5.000176