Patent ID: 6842285

Claim:
A method for generating a phase-modulated wave front of electromagnetic radiation comprising the steps of: providing an input wave front of electromagnetic radiation, E(x,y), performing a spatial amplitude modulation α(x,y) on the input wave front to generate a spatial amplitude distribution a(x,y) in the electromagnetic radiation in a plane transverse to a direction of propagation of the electromagnetic radiation, Fourier or Fresnel transforming the amplitude-modulated wave front a(x,y) to form a Fourier or Fresnel distribution of the amplitude-modulated wave front ã(f x ,f y ), said Fourier or Fresnel distribution comprising Fourier or Fresnel components, filtering the Fourier or Fresnel distribution by phase shifting one or more first components in relation to one or more second components of the Fourier or Fresnel distribution ã(f x ,f y ) and/or damping one or more third components in relation to one or more fourth components of the Fourier or Fresnel distribution ã(f x ,f y ) by a spatial filter having a filter function H(f x ,f y ) giving the phase shift and/or damping for each component of the Fourier or Fresnel distribution ã(f x ,f y ), and inverse Fourier or inverse Fresnel transforming the filtered electromagnetic radiation whereby a phase-modulated wave front o(x′,y′) is formed, said phase-modulated wave front being a function of at least the input wave front E(x,y), the amplitude modulation α(x,y), and the filter function H(f x ,f y ).