added polariations and adjusted tests

src/QEDfields.jl

@@ -18,7 +18,9 @@ end
 export AbstractBackgroundField, AbstractPulsedPlaneWaveField 
 export reference_momentum, domain, phase_duration, pulse_envelope, amplitude, generic_spectrum
 
+export polarization_vector 
+
 include("interfaces/background_field_interface.jl")
-include("polarisation.jl")
+include("polarization.jl")
 
 end

src/interfaces/background_field_interface.jl

@@ -106,7 +106,7 @@ end
 # amplitude functions
 
 function _amplitude(field::AbstractPulsedPlaneWaveField, pol::AbstractDefinitePolarization,  phi::Real)
-    return _oscillator(pol,phi)*_pulse_envelope(field,phi)
+    return oscillator(pol,phi)*_pulse_envelope(field,phi)
 end
 
 function _amplitude(field::AbstractPulsedPlaneWaveField, pol::AbstractDefinitePolarization, phi::AbstractVector{T}) where T<:Real

src/polarization.jl

@@ -0,0 +1,21 @@
+#################
+# polarization vectors
+# 
+# In this file, we provide an extension of the Polarizations of Photons from
+# QEDbase to define polarization states of background fields
+################
+#
+# TODO:
+#   * write doc strings
+#   * implement elliptical/circular polarisation
+
+@inline polarization_vector(pol::AbstractDefinitePolarization, mom) = base_state(Photon(),Incoming(), mom, pol)
+
+@inline oscillator(::PolX, x) = cos(x)
+@inline oscillator(::PolY, x) = sin(x)  
+@inline function oscillator(::AbstractIndefinitePolarization,x) 
+    sincos_res = sincos(x)
+    @inbounds cossin_res = (sincos_res[2], sincos_res[1])
+    return cossin_res
+end
+

test/downstream.jl

@@ -11,6 +11,19 @@ import QEDbase
 @testset "Integration: QEDbase" begin
 
     QEDbase_exports = names(QEDbase)
-    @test :SFourMomentum in QEDbase_exports
+
+    @testset "General" begin
+        @test :SFourMomentum in QEDbase_exports
+        @test :base_state in QEDbase_exports
+    end
+
+    @testset "Polarizations" begin
+        @test :PolarizationX in QEDbase_exports
+        @test :PolX in QEDbase_exports
+        @test :PolarizationY in QEDbase_exports
+        @test :PolY in QEDbase_exports
+        @test :AllPolarization in QEDbase_exports
+        @test :AllPol in QEDbase_exports
+    end
 end
 

test/polarization.jl

@@ -0,0 +1,29 @@
+
+using QEDbase
+using QEDfields
+using Random
+using IntervalSets
+
+RNG = MersenneTwister(137)
+ATOL = eps()
+RTOL = sqrt(eps())
+
+RND_MOM = SFourMomentum(rand(RNG,4))
+POL_SET = [PolX(), PolY()]
+
+@testset "polarization vectors" begin
+    @testset "$mom" for mom in [SFourMomentum(1,0,0,1),RND_MOM]
+        @testset "single $pol" for pol in POL_SET
+            pol_vec = polarization_vector(pol,mom)
+            @test isapprox(pol_vec*pol_vec, -one(eltype(pol_vec)), atol = ATOL, rtol = RTOL)
+            @test isapprox(pol_vec*mom, zero(eltype(mom)), atol = ATOL, rtol = RTOL)
+        end
+
+        @testset "both polarizations" begin
+            pol_vec1 = polarization_vector(PolX(),mom)
+            pol_vec2 = polarization_vector(PolY(),mom)
+
+            @test isapprox(pol_vec1*pol_vec2, zero(eltype(pol_vec1)), atol = ATOL, rtol = RTOL)
+        end
+    end
+end

test/runtests.jl

@@ -10,3 +10,7 @@ end
     include("interfaces/background_field_interface.jl")
 end
 
+@time @safetestset "polarization" begin
+    include("polarization.jl")
+end
+