A fast-Fourier-transform method of topography and interferometry is proposed. By computer processing of a noncontour type of fringe pattern, automatic discrimination is achieved between elevation and depression of the object or wave-front form, which has not been possible by the fringe-contour-generation techniques. The method has advantages over moire topography and conventional fringe-contour interferometry in both accuracy and sensitivity. Unlike fringe-scanning techniques, the method is easy to apply because it uses no moving components.

Fourier-transform method of fringe-pattern analysis for computer-based topography and interferometry

A 2018 update of the most accurate calculated and experimental static dipole polarizabilities of the neutral atoms in the Periodic Table from nuclear charge Z = 1 to 120 is given. Periodic ...

https://www.tandfonline.com/doi/pdf/10.1080/00268976.2018.1535143

2018 Table of static dipole polarizabilities of the neutral elements in the periodic table

Today, it is well known that light possesses a linear momentum which is along the propagation direction. Besides, scientists also discovered that light can possess an angular momentum (AM), a spin angular momentum (SAM) associated with circular polarization and an orbital angular momentum (OAM) owing to the azimuthally dependent phase. Even though such angular momenta are longitudinal in general, a SAM transverse to the propagation has opened up a variety of key applications [1]. In contrast, investigations of the transverse OAM are quite rare due to its complex nature. Here we demonstrate a simple method to generate a three dimensional (3D) optical wave packet with a controllable purely transverse OAM. Such a wave packet is a spatiotemporal (ST) vortex, which resembles an advancing cyclone, with optical energy flowing in the spatial and temporal dimension. Contrary to the transverse SAM, the magnitude of the transverse OAM carried by the photonic cyclone is scalable to a larger value by simple adjustments. Since the ST vortex carries a controllable OAM in the unique transverse dimension, it has a strong potential for novel applications that may not be possible otherwise. The scheme reported here can be readily adapted for the other spectra regime and different wave fields, opening tremendous opportunities for the study and applications of ST vortex in much broader scopes.

Photonic Cyclone: spatiotemporal optical vortex with controllable transverse orbital angular momentum.

Today, it is well known that light possesses a linear momentum that is along the propagation direction. Besides, scientists also discovered that light can possess an angular momentum, a spin angular momentum (SAM) associated with circular polarization and an orbital angular momentum (OAM) owing to the azimuthally dependent phase. Even though such angular momenta are longitudinal in general, an SAM transverse to the propagation direction has opened up a variety of key applications1. In contrast, investigations of the transverse OAM are rare due to its complex nature. Here, we demonstrate a three-dimensional wave packet that is a spatiotemporal (ST) optical vortex with a controllable purely transverse OAM. Contrary to the transverse SAM, the magnitude of the transverse OAM carried by the ST vortex is scalable to a larger value by simple adjustments. Since the ST vortex carries a controllable OAM uniquely in the transverse dimension, it has strong potential for novel applications that may not be possible otherwise. The scheme reported here can be readily adapted for other spectral regimes and different wave fields, opening opportunities for the study and applications of ST vortices in a wide range of areas. By applying a spiral phase in a pulse shaper, a three-dimensional wave packet, which is a spatiotemporal optical vortex with a controllable purely transverse orbital angular momentum, is demonstrated.

Generation of spatiotemporal optical vortices with controllable transverse orbital angular momentum

(INVITED) Vortex solitons: Old results and new perspectives

We present the first experimental evidence, supported by theory and simulation, of spatiotemporal optical vortices (STOVs). Quantized STOVs are a fundamental element of the nonlinear collapse and subsequent propagation of short optical pulses in material media. A STOV consists of a ring-shaped null in the electromagnetic field about which the phase is spiral, forming a dynamic torus which is concentric with and tracks the propagating pulse. Depending on the sign of the material dispersion, the local electromagnetic energy flow is saddle or spiral about the STOV. STOVs are born and evolve conserving topological charge; they can be simultaneously created in pairs with opposite windings, or generated from a point null. Our results, here obtained for optical pulse collapse and filamentation in air, are generalizable to broad class of nonlinearly propagating waves.

Spatio-temporal optical vortices

Spatiotemporal Optical Vortices

We present spatially resolved measurements of energy deposition into atmospheric air by femtosecond laser filaments. Single filaments formed with varying laser pulse energy and pulsewidth were examined using longitudinal interferometry, sonographic probing, and direct energy loss measurements. We measure peak and average energy absorption of ∼4  μJ/cm and ∼1  μJ/cm for input pulse powers up to ∼6 times the critical power for self-focusing.

Energy deposition of single femtosecond filaments in the atmosphere

Advanced pulsed cryogenic molecular beam electric deflection methods involving position-sensitive mass spectrometry and 7.87 eV ionizing radiation were used for the first time to measure the polarizabilities of more than half of the metallic elements in the periodic table.

/pdf/measured-atomic-ground-state-polarizabilities-of-35-metallic-19a1qqnt48.pdf

Measured atomic ground-state polarizabilities of 35 metallic elements

http://absimage.aps.org/image/MAR15/MWS_MAR15-2014-007687.pdf

Ilia Larkin

Papers

Spatio-temporal optical vortices

Spatiotemporal Optical Vortices

Energy deposition of single femtosecond filaments in the atmosphere

Measured atomic ground-state polarizabilities of 35 metallic elements

Measured Atomic Ground State Polarizabilities of 35 Metallic Elements