Mutual spatiotemporal coherence of optical fields in an amplitude-splitting interferometer

Modulations in Stokes parameters due to electromagnetic longitudinal spatio-temporal coherence

“…The intensity and polarization modulations arising due to the superposition of the fields coming from the two sources are governed by the interference law derived in equation (7). The potential of the law lies in the fact that the position of the sources can be located in the longitudinal as well as the transverse direction.…”

“…The Stokes parameters (n = 0:3) at point O due to point sources s 1 and s 2 , obtained from equation (7), are expressed as (eliminate integration as only single-point source contributes)…”

“…The angular spectrum controls the spatial coherence, whereas the temporal coherence is governed by the frequency spectrum [6]. Hence, in general, the longitudinal coherence is called the longitudinal spatio-temporal coherence [7,8]. A broader spectrum (angular or frequency) determines the coherence length of the source in the longitudinal direction, as evident from the relation 1 Lc ≈ 1 ρ ∥ + 1 lc [3,9], where L c is the effective longitudinal coherence length, * Author to whom any correspondence should be addressed.…”

Investigation of longitudinal spatial coherence for electromagnetic optical fields

“…For optical fields, the field correlation between different points in the direction of its propagation has been mainly understood as temporal coherence [1]. However, depending on the divergence of the field, coherence in the longitudinal direction can be seen as the combined effect of the frequency spectrum and angular spectrum [2][3][4][5][6][7][8]. Existing studies in this direction emphasize on the role of the size of an extended source in determining longitudinal spatial coherence (LSC) [9][10][11], and use of interferometric schemes to determine LSC for scalar light fields [4,11].…”

“…However, depending on the divergence of the field, coherence in the longitudinal direction can be seen as the combined effect of the frequency spectrum and angular spectrum [2][3][4][5][6][7][8]. Existing studies in this direction emphasize on the role of the size of an extended source in determining longitudinal spatial coherence (LSC) [9][10][11], and use of interferometric schemes to determine LSC for scalar light fields [4,11]. It has been demonstrated that the angular diversity of the field results in amplitude-phase transformation and thus effective coherence length (L c ) in longitudinal direction is given in terms of temporal coherence length (l c ) and longitudinal spatial coherence length (ρ ) as 1 L C ≈ 1 l c + 1 ρ [2,3].…”