Publications by authors named "Emmanuel Cagniot"
Article Synopsis
- The proposed device measures wavefront distortions with high sensitivity using continuous position sensitive detectors, eliminating the need for reconstruction processes.
- Experimental results show its effectiveness in detecting small refractive index changes in laser materials induced by pump effects.
- The device also successfully identifies phase discontinuities and enhances measurements of sharp phase variations when compared to traditional Shack-Hartmann methods.
Transverse superresolution technique involving rectified Laguerre-Gaussian LG(p)⁰ beams.
J Opt Soc Am A Opt Image Sci Vis
August 2011
A promising technique has been proposed recently [Opt. Commun. 284, 1331 (2011), Opt.
View Article and Find Full Text PDFA new and efficient technique for measuring weak optical nonlinearities is reported. Like Z scan, its implementation is basic, both experimentally and theoretically, but leads to an improved sensitivity of λ/5.10⁴, which represents, to date, one of the highest observed enhancements.
View Article and Find Full Text PDFVariant of the method of Fox and Li dedicated to intracavity laser beam shaping.
J Opt Soc Am A Opt Image Sci Vis
March 2011
Article Synopsis
- The paper introduces a new method for shaping laser beams in resonators using diffractive optics, building on the previous work of Fox and Li.
- This approach focuses on optimizing the desired output field rather than starting with the optical system, iterating the process until the desired output matches the actual output.
- The authors demonstrate the technique by creating single cylindrical TEM(p0) modes using a π-phase plate in a plano-concave cavity, confirming its effectiveness through experimental validation and numerical predictions.
Cascades of pi-phase plates: a transparent diffractive focusing system.
J Opt Soc Am A Opt Image Sci Vis
July 2010
Article Synopsis
- Researchers investigate how to focus light using diffraction instead of traditional refractive lenses.
- The study shows that using pi-phase plates instead of hard-edge apertures reduces light absorption losses while enhancing focus on Gaussian beams.
- A new model is introduced to design these optical cascades efficiently, allowing for better placement and sizing of components without extensive optimization.
Modeling the propagation of apertured high-order Laguerre-Gaussian beams by a user-friendly version of the mode expansion method.
J Opt Soc Am A Opt Image Sci Vis
March 2010
The mode expansion method (MEM) models the propagation of an apertured beam by expressing the diffracted field as a finite series of Laguerre-Gaussian or Hermite-Gaussian modes. An optimal expansion parameter set (beam waist of the modes and its location) reduces the number of modes, which is difficult to derive, especially for high-order incident beams. We propose a user-friendly version of the MEM in which the expansion parameter set and the suitable number of modes are simply deduced from the approximation of the apertured incident beam.
View Article and Find Full Text PDFAdaptive Laguerre-Gaussian variant of the Gaussian beam expansion method.
J Opt Soc Am A Opt Image Sci Vis
November 2009
Article Synopsis
- The method discussed involves expanding the Bessel function J0 from the Fresnel-Kirchhoff integral into a sum of complex Gaussian functions to analyze the behavior of a Laguerre-Gaussian beam passing through a hard-edge aperture.
- The effectiveness of this approximation relies on optimizing the number of expansion coefficients, which affects the accuracy of the results.
- An alternative approach is proposed, where J0 is expanded using collimated Laguerre-Gaussian functions, and the optimal number of these functions is determined recursively based on specific parameters.