1
|
Saghafi S, Becker K, Gori F, Foroughipour M, Bollwein C, Foroughipour M, Steiger K, Weichert W, Dodt HU. Engineering a better light sheet in an axicon-based system using a flattened Gaussian beam of low order. JOURNAL OF BIOPHOTONICS 2022; 15:e202100342. [PMID: 35104051 DOI: 10.1002/jbio.202100342] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 01/05/2022] [Accepted: 01/30/2022] [Indexed: 06/14/2023]
Abstract
Lasers are fundamental tools in research and development. The shape of an incident laser beam directly affects the results, when it propagates through complex structured meso-aspheric optical elements. In conic-based systems utilizing elements such as axicons, the impact of secondary lobes is mostly overlooked, although the intensity distributions at the central spot and the side-lobes directly affect the beam properties. We investigate the interaction of two axicons (160° and 170°) with incident beams approximated by Gaussian, high-order Flattened-Gaussian, and low-order Flattened-Gaussian functions. We demonstrate that replacing an incident Gaussian beam with a low-order Flattened-Gaussian beam reduces the secondary lobes and significantly improves the uniformity of the intensity profile. We practically applied this effect in engineering a conic-aspheric-based static light-sheet microscope producing markedly improved results.
Collapse
Affiliation(s)
- Saiedeh Saghafi
- Section of Bioelectronics, Institut für Festkörperelektronik (FKE), Vienna, Austria
| | - Klaus Becker
- Section of Bioelectronics, Institut für Festkörperelektronik (FKE), Vienna, Austria
- Section of Bioelectronics, Center for Brain Research, Medical University of Vienna, Vienna, Austria
| | - Franco Gori
- Dipartimento di Ingegneria, Roma Tre University, Rome, Italy
| | - Massih Foroughipour
- Section of Bioelectronics, Institut für Festkörperelektronik (FKE), Vienna, Austria
- Section of Bioelectronics, Center for Brain Research, Medical University of Vienna, Vienna, Austria
| | | | - Meraaj Foroughipour
- Section of Bioelectronics, Institut für Festkörperelektronik (FKE), Vienna, Austria
| | - Katja Steiger
- Institute of Pathology, Technical University of Munich, Munich, Germany
| | - Wilko Weichert
- Institute of Pathology, Technical University of Munich, Munich, Germany
| | - Hans-Ulrich Dodt
- Section of Bioelectronics, Institut für Festkörperelektronik (FKE), Vienna, Austria
- Section of Bioelectronics, Center for Brain Research, Medical University of Vienna, Vienna, Austria
| |
Collapse
|
2
|
High-Flexibility Control of Structured Light with Combined Adaptive Optical Systems. PHOTONICS 2022. [DOI: 10.3390/photonics9010042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Combining the specific advantages of high-resolution liquid-crystal-on-silicon spatial light modulators (LCoS-SLMs) and reflective or refractive micro-electro-mechanical systems (MEMS) presents new prospects for the generation of structured light fields. In particular, adaptive self-apodization schemes can significantly reduce diffraction by low-loss spatial filtering. The concept enables one to realize low-dispersion shaping of nondiffracting femtosecond wavepackets and to temporally switch, modulate or deflect spatially structured beams. Adaptive diffraction management by structured illumination is demonstrated for piezo-based and thermally actuated axicons, spiral phase plates (SPPs) and Fresnel bi-mirrors. Improved non-collinear autocorrelation with angular-tunable Fresnel-bi-mirrors via self-apodized illumination and phase contrast of an SLM is proposed. An extension of the recently introduced nondiffractive Talbot effect to a tunable configuration by combining an SLM and a fluid lens is reported. Experimental results for hexagonal as well as orthogonal array beams are presented.
Collapse
|
3
|
Propagation-Invariant Off-Axis Elliptic Gaussian Beams with the Orbital Angular Momentum. PHOTONICS 2021. [DOI: 10.3390/photonics8060190] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We studied paraxial light beams, obtained by a continuous superposition of off-axis Gaussian beams with their phases chosen so that the whole superposition is invariant to free-space propagation, i.e., does not change its transverse intensity shape. Solving a system of five nonlinear equations for such superpositions, we obtained an analytical expression for a propagation-invariant off-axis elliptic Gaussian beam. For such an elliptic beam, an analytical expression was derived for the orbital angular momentum, which was shown to consist of two terms. The first one is intrinsic and describes the momentum with respect to the beam center and is shown to grow with the beam ellipticity. The second term depends parabolically on the distance between the beam center and the optical axis (similar to the Steiner theorem in mechanics). It is shown that the ellipse orientation in the transverse plane does not affect the normalized orbital angular momentum. Such elliptic beams can be used in wireless optical communications, since their superpositions do not interfere in space, if they do not interfere in the initial plane.
Collapse
|
4
|
Froehly L, Courvoisier F, Brunner D, Larger L, Devaux F, Lantz E, Dudley JM, Jacquot M. Advancing Fourier: space-time concepts in ultrafast optics, imaging, and photonic neural networks. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2019; 36:C69-C77. [PMID: 31873701 DOI: 10.1364/josaa.36.000c69] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Accepted: 10/03/2019] [Indexed: 06/10/2023]
Abstract
The concepts of Fourier optics were established in France in the 1940s by Pierre-Michel Duffieux, and laid the foundations of an extensive series of activities in the French research community that have touched on nearly every aspect of contemporary optics and photonics. In this paper, we review a selection of results where applications of the Fourier transform and transfer functions in optics have been applied to yield significant advances in unexpected areas of optics, including the spatial shaping of complex laser beams in amplitude and in phase, real-time ultrafast measurements, novel ghost imaging techniques, and the development of parallel processing methodologies for photonic artificial intelligence.
Collapse
|
5
|
Bock M, Treffer A, Grunwald R. Nondiffracting self-imaging of ultrashort wavepackets. OPTICS LETTERS 2017; 42:2374-2377. [PMID: 28614314 DOI: 10.1364/ol.42.002374] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Accepted: 05/17/2017] [Indexed: 06/07/2023]
Abstract
Self-imaging of ultrashort-pulsed nondiffracting needle beams, i.e., fringe-free Bessel beams, is analyzed. In contrast to the classical diffractive Talbot effect, pulse revivals with minimum spectral and temporal distortion are obtained. Robustness is further enhanced by self-reconstruction. The high-fidelity pulse transfer enables spatial and temporal multiplexing in free space without the need for a nonlinear medium, even at pulse durations down to the few-cycle range.
Collapse
|
6
|
Grunwald R, Elsaesser T, Bock M. Spatio-temporal coherence mapping of few-cycle vortex pulses. Sci Rep 2014; 4:7148. [PMID: 25413789 PMCID: PMC4239570 DOI: 10.1038/srep07148] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Accepted: 11/03/2014] [Indexed: 11/10/2022] Open
Abstract
Light carrying an orbital angular momentum (OAM) displays an optical phase front rotating in space and time and a vanishing intensity, a so-called vortex, in the center. Beyond continuous-wave vortex beams, optical pulses with a finite OAM are important for many areas of science and technology, ranging from the selective manipulation and excitation of matter to telecommunications. Generation of vortex pulses with a duration of few optical cycles requires new methods for characterising their coherence properties in space and time. Here we report a novel approach for flexibly shaping and characterising few-cycle vortex pulses of tunable topological charge with two sequentially arranged spatial light modulators. The reconfigurable optical arrangement combines interferometry, wavefront sensing, time-of-flight and nonlinear correlation techniques in a very compact setup, providing complete spatio-temporal coherence maps at minimum pulse distortions. Sub-7 fs pulses carrying different optical angular momenta are generated in single and multichannel geometries and characterised in comparison to zero-order Laguerre-Gaussian beams. To the best of our knowledge, this represents the shortest pulse durations reported for direct vortex shaping and detection with spatial light modulators. This access to space-time coupling effects with sub-femtosecond time resolution opens new prospects for tailored twisted light transients of extremely short duration.
Collapse
Affiliation(s)
- R Grunwald
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Strasse 2a, 12489 Berlin, Germany
| | - T Elsaesser
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Strasse 2a, 12489 Berlin, Germany
| | - M Bock
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Strasse 2a, 12489 Berlin, Germany
| |
Collapse
|
7
|
Majus D, Tamošauskas G, Gražulevičiūtė I, Garejev N, Lotti A, Couairon A, Faccio D, Dubietis A. Nature of spatiotemporal light bullets in bulk Kerr media. PHYSICAL REVIEW LETTERS 2014; 112:193901. [PMID: 24877940 DOI: 10.1103/physrevlett.112.193901] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Indexed: 06/03/2023]
Abstract
We present a detailed experimental investigation which uncovers the nature of light bullets generated from self-focusing in a bulk dielectric medium with Kerr nonlinearity in the anomalous group velocity dispersion regime. By high dynamic range measurements of three-dimensional intensity profiles, we demonstrate that the light bullets consist of a sharply localized high-intensity core, which carries the self-compressed pulse and contains approximately 25% of the total energy, and a ring-shaped spatiotemporal periphery. Subdiffractive propagation along with dispersive broadening of the light bullets in free space after they exit the nonlinear medium indicate a strong space-time coupling within the bullet. This finding is confirmed by measurements of a spatiotemporal energy density flux that exhibits the same features as a stationary, polychromatic Bessel beam, thus highlighting the nature of the light bullets.
Collapse
Affiliation(s)
- D Majus
- Department of Quantum Electronics, Vilnius University, Saulėtekio Avenue 9, Building 3, LT-10222 Vilnius, Lithuania
| | - G Tamošauskas
- Department of Quantum Electronics, Vilnius University, Saulėtekio Avenue 9, Building 3, LT-10222 Vilnius, Lithuania
| | - I Gražulevičiūtė
- Department of Quantum Electronics, Vilnius University, Saulėtekio Avenue 9, Building 3, LT-10222 Vilnius, Lithuania
| | - N Garejev
- Department of Quantum Electronics, Vilnius University, Saulėtekio Avenue 9, Building 3, LT-10222 Vilnius, Lithuania
| | - A Lotti
- Dipartimento di Scienza e Alta Tecnologia, Università degli Studi dell'Insubria, Via Valleggio 11, I-22100 Como, Italy
| | - A Couairon
- Centre de Physique Théorique, CNRS, Ecole Polytechnique, F-91128 Palaiseau, France
| | - D Faccio
- School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14-4AS, United Kingdom
| | - A Dubietis
- Department of Quantum Electronics, Vilnius University, Saulėtekio Avenue 9, Building 3, LT-10222 Vilnius, Lithuania
| |
Collapse
|
8
|
Froehly L, Jacquot M, Lacourt PA, Dudley JM, Courvoisier F. Spatiotemporal structure of femtosecond Bessel beams from spatial light modulators. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2014; 31:790-793. [PMID: 24695141 DOI: 10.1364/josaa.31.000790] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We numerically investigate the spatiotemporal structure of Bessel beams generated with spatial light modulators (SLMs). Grating-like phase masks enable the spatial filtering of undesired diffraction orders produced by SLMs. Pulse front tilt and temporal broadening effects are investigated. In addition, we explore the influence of phase wrapping and show that the spatiotemporal structure of SLM-generated femtosecond Bessel beams is similar to Bessel X-pulses at short propagation distance and to subluminal pulsed Bessel beams at long propagation distance.
Collapse
|
9
|
Adaptive Generation and Diagnostics of Linear Few-Cycle Light Bullets. APPLIED SCIENCES-BASEL 2013. [DOI: 10.3390/app3010139] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|