Zeroth- and first-order long range non-diffracting GausstextendashBessel beams generated by annihilating multiple-charged optical vortices

Author(s):

Stoyanov, Lyubomir; Zhekova, Maya; Stefanov, Aleksander; Stefanov, Ivan; Paulus, Gerhard G. & Dreischuh, Alexander

Abstract:

“We demonstrate an alternative approach for generating zeroth- and first-order long range non-diffracting Gauss–Bessel beams (GBBs). Starting from a Gaussian beam, the key point is the creation of a bright ring-shaped beam with a large radius-to-width ratio, which is subsequently Fourier-transformed by a thin lens. The phase profile required for creating zeroth-order GBBs is flat and helical for first-order GBBs with unit topological charge (TC). Both the ring-shaped beam and the required phase profile can be realized by creating highly charged optical vortices by a spatial light modulator and annihilating them by using a second modulator of the same type. The generated long-range GBBs are proven to have negligible transverse evolution up to 2 m and can be regarded as non-diffracting. The influences of the charge state of the TCs, the propagation distance behind the focusing lens, and the GBB profiles on the relative intensities of the peak/rings are discussed. The method is much more efficient as compared to this using annular slits in the back focal plane of lenses. Moreover, at large propagation distances the quality of the generated GBBs significantly surpasses this of GBBs created by low angle axicons. The developed analytical model reproduces the experimental data. The presented method is flexible, easily realizable by using a spatial light modulator, does not require any special optical elements and, thus, is accessible in many laboratories.”

Link to Publications Page

Publication: Scientific Reports
Issue/Year: Scientific Reports, Volume 10; Number 1; 2020
DOI: 10.1038/s41598-020-78613-7

Zeroth- and first-order long range non-diffracting GausstextendashBessel beams generated by annihilating multiple-charged optical vortices

Author(s):

Stoyanov, Lyubomir; Zhekova, Maya; Stefanov, Aleksander; Stefanov, Ivan; Paulus, Gerhard G. & Dreischuh, Alexander

Abstract:

“We demonstrate an alternative approach for generating zeroth- and first-order long range non-diffracting Gauss–Bessel beams (GBBs). Starting from a Gaussian beam, the key point is the creation of a bright ring-shaped beam with a large radius-to-width ratio, which is subsequently Fourier-transformed by a thin lens. The phase profile required for creating zeroth-order GBBs is flat and helical for first-order GBBs with unit topological charge (TC). Both the ring-shaped beam and the required phase profile can be realized by creating highly charged optical vortices by a spatial light modulator and annihilating them by using a second modulator of the same type. The generated long-range GBBs are proven to have negligible transverse evolution up to 2 m and can be regarded as non-diffracting. The influences of the charge state of the TCs, the propagation distance behind the focusing lens, and the GBB profiles on the relative intensities of the peak/rings are discussed. The method is much more efficient as compared to this using annular slits in the back focal plane of lenses. Moreover, at large propagation distances the quality of the generated GBBs significantly surpasses this of GBBs created by low angle axicons. The developed analytical model reproduces the experimental data. The presented method is flexible, easily realizable by using a spatial light modulator, does not require any special optical elements and, thus, is accessible in many laboratories.”

Link to Publications Page

Publication: Scientific Reports
Issue/Year: Scientific Reports, Volume 10; Number 1; 2020
DOI: 10.1038/s41598-020-78613-7

Laser photonic-reduction stamping for graphene-based micro-supercapacitors ultrafast fabrication

Author(s):

Yuan, Yongjiu; Jiang, Lan; Li, Xin; Zuo, Pei; Xu, Chenyang; Tian, Mengyao; Zhang, Xueqiang; Wang, Sumei; Lu, Bing; Shao, Changxiang; Zhao, Bingquan; Zhang, Jiatao; Qu, Liangti & Cui, Tianhong

Abstract:

“Micro-supercapacitors are promising miniaturized energy storage devices that have attracted considerable research interest. However, their widespread use is limited by inefficient microfabrication technologies and their low energy density. Here, a flexible, designable micro-supercapacitor can be fabricated by a single pulse laser photonic-reduction stamping. A thousand spatially shaped laser pulses can be generated in one second, and over 30,000 micro-supercapacitors are produced within 10 minutes. The micro-supercapacitor and narrow gaps were dozens of microns and 500 nm, respectively. With the unique three-dimensional structure of laser-induced graphene based electrode, a single micro-supercapacitor exhibits an ultra-high energy density (0.23 Wh cm−3), an ultra-small time constant (0.01 ms), outstanding specific capacitance (128 mF cm−2 and 426.7 F cm−3) and a long-term cyclability. The unique technique is desirable for a broad range of applications, which surmounts current limitations of high-throughput fabrication and low energy density of micro-supercapacitors.”

Link to Publications Page

Publication: Nature Communications
Issue/Year: Nature Communications, Volume 11; Number 1; 2020
DOI: 10.1038/s41467-020-19985-2

Partial aperture imaging system based on sparse point spread holograms and nonlinear cross-correlations

Author(s):

Bulbul, Angika & Rosen, Joseph

Abstract:

“Partial aperture imaging system (PAIS) is a recently developed concept in which the traditional disc-shaped aperture is replaced by an aperture with a much smaller area and yet its imaging capabilities are comparable to the full aperture systems. Recently PAIS was demonstrated as an indirect incoherent digital three-dimensional imaging technique. Later it was successfully implemented in the study of the synthetic marginal aperture with revolving telescopes (SMART) to provide superresolution with subaperture area that was less than one percent of the area of the full synthetic disc-shaped aperture. In the study of SMART, the concept of PAIS was tested by placing eight coded phase reflectors along the boundary of the full synthetic aperture. In the current study, various improvements of PAIS are tested and its performance is compared with the other equivalent systems. Among the structural changes, we test ring-shaped eight coded phase subapertures with the same area as of the previous circular subapertures, distributed along the boundary of the full disc-shaped aperture. Another change in the current system is the use of coded phase mask with a point response of a sparse dot pattern. The third change is in the reconstruction process in which a nonlinear correlation with optimal parameters is implemented. With the improved image quality, the modified-PAIS can save weight and cost of imaging devices in general and of space telescopes in particular. Experimental results with reflective objects show that the concept of coded aperture extends the limits of classical imaging”

Link to Publications Page

Publication: Scientific Reports
Issue/Year: Scientific Reports, Volume 10; Number 1; 2020
DOI: 10.1038/s41598-020-77912-3

Distinguishing intrinsic photon correlations from external noise with frequency-resolved homodyne detection

Author(s):

Lüders, Carolin & Assmann, Marc

Abstract:

“In this work, we apply homodyne detection to investigate the frequency-resolved photon statistics of a cw light field emitted by a driven-dissipative semiconductor system in real time. We demonstrate that studying the frequency dependence of the photon number noise allows us to distinguish intrinsic noise properties of the emitter from external noise sources such as mechanical noise while maintaining a sub-picosecond temporal resolution. We further show that performing postselection on the recorded data opens up the possibility to study rare events in the dynamics of the emitter. By doing so, we demonstrate that in rare instances, additional external noise may actually result in reduced photon number noise in the emission”

Link to Publications Page

Publication: Scientific Reports
Issue/Year: Scientific Reports, Volume 10; Number 1; 2020
DOI: 10.1038/s41598-020-79686-0

Gigantic vortical differential scattering as a monochromatic probe for multiscale chiral structures

Author(s):

Ni, Jincheng; Liu, Shunli; Wu, Dong; Lao, Zhaoxin; Wang, Zhongyu; Huang, Kun; Ji, Shengyun; Li, Jiawen; Huang, Zhixiang; Xiong, Qihua; Hu, Yanlei; Chu, Jiaru & Qiu, Cheng-Wei

Abstract:

“Spin angular momentum of light is vital to investigate enantiomers characterized by circular dichroism (CD), widely adopted in biology, chemistry, and material science. However, to discriminate chiral materials with multiscale features, CD spectroscopy normally requires wavelength-swept laser sources as well as wavelength-specific optical accessories. Here, we experimentally demonstrate an orbital-angular-momentum-assisted approach to yield chiroptical signals with monochromatic light. The gigantic vortical differential scattering (VDS) of ∼120% is achieved on intrinsically chiral microstructures fabricated by femtosecond laser. The VDS measurements can robustly generate chiroptical properties on microstructures with varying geometric features (e.g., diameters and helical pitches) and detect chiral molecules with high sensitivity. This VDS scheme lays a paradigm-shift pavement toward efficiently chiroptical discrimination of multiscale chiral structures with photonic orbital angular momentum. It simplifies and complements the conventional CD spectroscopy, opening possibilities for measuring weak optical chirality, especially on mesoscale chiral architectures and macromolecules.”

Link to Publications Page

Publication: Proceedings of the National Academy of Sciences
Issue/Year: Proceedings of the National Academy of Sciences, Volume 118; Number 2; Pages e2020055118; 2020
DOI: 10.1073/pnas.2020055118

New Version of Pattern Generator Software

Spatial Light Modulator Pattern Generator SoftwareThe release of version 5 of the Pattern Generator software is really a big step forward, as we integrated core components of the Display SDK into Pattern Generator, along with almost all Display SDK features which are available now. We also reworked a lot of the user interface to make these new functions more accessible and give the user a better overview of the optical functions applied to the data. (more…)

Major update for PLUTO-2 Phase Only Spatial Light Modulators

PLUTO-2.1 Spatial Light ModulatorWe recently released a major update for the PLUTO-2 SLM series. The PLUTO-2.1 features a faster pulse addressing frequeny which provides a higher dynamic range for addressing voltages. With an adjusted drive sequence and configurations the phase stability was further improved and with that, the diffraction efficiencies could also be enhanced.

The higher bandwith also increases flexibility in terms of configurations. The SLM devices come with (more…)

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