Created
October 17, 2018 21:06
-
-
Save mpreciado/f808934f8f77e4ceb06a48b1cede05ab to your computer and use it in GitHub Desktop.
Compensating beam designed in Miguel A. Preciado, Kishan Dholakia, and Michael Mazilu, "Generation of attenuation-compensating Airy beams," Opt. Lett. 39, 4950-4953 (2014)
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
% compensating Airy beam in Air | |
% Author: Miguel Preciado @miguelSciLight | |
% See publication below for details: | |
% Miguel A. Preciado, Kishan Dholakia, and Michael Mazilu, "Generation of attenuation-compensating Airy beams," Opt. Lett. 39, 4950-4953 (2014) | |
% https://www.researchgate.net/publication/284505770_Attenuation_compensating_Airy_beams_generated_by_using_a_digital_micro-mirror_device | |
% Please cite the paper above for reference. | |
close all; | |
clear all; | |
%refractive index (air). | |
nmedium=1; | |
%wavelength in vacuum | |
lambda0=532e-9; | |
%wavelength in medium | |
lambda=lambda0/nmedium; | |
%% boring bits | |
% N=684; | |
factor=1; | |
TAMX=factor*0.37e-2; | |
N=factor*684; | |
%% | |
% Spatial window | |
x=TAMX*(-N/2:N/2-1)/N; | |
%spatial frequency, acording to DFT rules. | |
vx=((1:length(x))-length(x)/2) / (max(x)-min(x)); | |
%% | |
%% | |
fac1=1; | |
fac2=2; | |
Axmax=fac2*fac1*0.3*0.1e-2; | |
Atetamax=fac1*0.5*532e-9/21.6e-6; | |
teta=vx*lambda; | |
Avxmax=Atetamax/lambda; | |
%% This term introduce the amplitude modulation, leading to the compensating effect. Change 1.7 factor for other compensations. | |
SpectAmp=exp(1.7*vx/Avxmax); | |
%% Set the ammount of cubic phase introduced. | |
a=-Axmax/(Atetamax.^2); | |
% Apodized window, to avoid diffraction of sharp spectral edges that would distort the resulting beam otherwise. | |
WindowAiry=exp(-(vx.^8)/(2*((0.75*Avxmax)^8))); | |
% Spatial shift. | |
shift=0; %set z0 | |
shiftPhase=exp(j*2*pi*vx*shift); | |
% Airy beam in frequency | |
F_airy_0=exp(j*2*pi*(a/3)*(lambda^2)*((vx).^3)); | |
%range of distances for simmulation | |
zz=4e-2*(-1:0.025:1); | |
II=1; | |
for(z=zz) | |
diffraction=exp(j*pi*lambda*z*(vx.^2)); | |
F_airy=F_airy_0.*SpectAmp.*WindowAiry.*shiftPhase.*diffraction; | |
f_airy(:,II)=fftshift((ifft(fftshift(F_airy)))); | |
II=II+1; | |
end | |
imagesc(zz*1e3,x*1e3,abs(f_airy).^2);colormap hot; | |
xlabel('z [mm]'); | |
ylabel('x [mm]'); |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment