From Event: SPIE Commercial + Scientific Sensing and Imaging, 2018
Diffractive spreading is a fundamental property of light and inversely proportional to the beam waist of a propagating beam. For instance, a Gaussian beam at a wavelength of 800 nm focused into 7 micrometers full-width at half maximum (FWHM) at its beam waist would only have 137 micrometers Rayleigh range—the propagation distance from the waist for a beam to double its cross section. Here, we demonstrate a diffraction-free space-time light sheet (one-dimensional pulsed beam) with 7 micrometers FWHM propagating in free space for 25 mm while preserving its spatial features. By introducing a highly correlated spatio-temporal spectrum via a two-dimensional pulse shaper (consisting of a phase-only reflective spatial light modulator, a grating and a few cylindrical lenses), we generate various light sheets with arbitrary beam profiles at the pulse center and diffraction-free propagation distance of approximately 200 Rayleigh range that corresponds to its beam waist size at the pulse center. Arbitrary light-sheet profiles also include hollow sheets (bottle beams) and even Airy light sheets that are only transversely accelerating in the local time frame of the pulse and acceleration-free as a function of propagation distance. Moreover, we obtain the spatio-temporal beam profiles of the light sheets by experimentally measuring the complex spectra and performing computational two-dimensional Fourier transformations. Light sheets with arbitrary beam profiles and controllable spectrum properties may be instrumental in super-resolution light-sheet microscopy for 3D bio-imaging, nonlinear and multimodality spectroscopy, standoff detection of chemicals, and one-dimensional plasma and filamentation generation.
Hasan E. Kondakci and Ayman F. Abouraddy, "Diffraction-free light sheets with arbitrary beam profiles (Conference Presentation)," Proc. SPIE 10666, Three-Dimensional Imaging, Visualization, and Display 2018, 106660X (Presented at SPIE Commercial + Scientific Sensing and Imaging: April 17, 2018; Published: 15 May 2018); https://doi.org/10.1117/12.2305788.5783315126001.
Conference Presentations are recordings of oral presentations given at SPIE conferences and published as part of the proceedings. They include the speaker's narration with video of the slides and animations. Most include full-text papers. Interactive, searchable transcripts and closed captioning are now available for most presentations.
Search our growing collection of more than 18,000 conference presentations, including many plenaries and keynotes.