From 536006c0880ef3a442ca9891b760eb06c53694aa Mon Sep 17 00:00:00 2001
From: miroox <miroox@outlook.com>
Date: Wed, 17 Jun 2020 17:03:25 +0800
Subject: [PATCH] detail doc string

---
 docs/src/index.md          |  2 ++
 src/angular_spectrum.jl    | 12 ++++++++++++
 src/fresnel_diffraction.jl | 28 ++++++++++++++++++++++++++++
 3 files changed, 42 insertions(+)

diff --git a/docs/src/index.md b/docs/src/index.md
index 4e8cec3..a32ea39 100644
--- a/docs/src/index.md
+++ b/docs/src/index.md
@@ -1,5 +1,7 @@
 # OpticalPropagation.jl
 
+A package of useful optical propagation methods.
+
 ```@index
 ```
 
diff --git a/src/angular_spectrum.jl b/src/angular_spectrum.jl
index a61899e..0963036 100644
--- a/src/angular_spectrum.jl
+++ b/src/angular_spectrum.jl
@@ -2,6 +2,18 @@
     angular_spectrum(Uin, d, λ, lx, ly)
 
 calculate the propagation light field based on the angular spectrum.
+
+## Parameters
+
+- `Uin::AbstractArray{<:Number,2}`: Complex array of input complex amplitude.
+- `d::Real`: Distance to propagate in metres.
+- `λ::Real`: Wavelength of light to propagate.
+- `lx::Real`: The physical size of the input data along the x-axis.
+- `ly::Real`: The physical size of the input data along the y-axis.
+
+## Returns
+
+- `::Array{<:Number,2}`: Complex amplitude data after propagation.
 """
 function angular_spectrum(Uin::AbstractArray{<:Number,2}, d::Real, λ::Real, lx::Real, ly::Real)
     tf = (u, v) -> 1-u^2-v^2>=0 ? exp(2im*pi*d/λ*sqrt(1-u^2-v^2)) : 0
diff --git a/src/fresnel_diffraction.jl b/src/fresnel_diffraction.jl
index bddbf75..3f793fa 100644
--- a/src/fresnel_diffraction.jl
+++ b/src/fresnel_diffraction.jl
@@ -2,6 +2,18 @@
     fresnel_diffraction_double(Uin, d, λ, lx, ly)
 
 calculate the propagation light field based on the Fresnel diffraction with double Fourier transform.
+
+## Parameters
+
+- `Uin::AbstractArray{<:Number,2}`: Complex array of input complex amplitude.
+- `d::Real`: Distance to propagate in metres.
+- `λ::Real`: Wavelength of light to propagate.
+- `lx::Real`: The physical size of the input data along the x-axis.
+- `ly::Real`: The physical size of the input data along the y-axis.
+
+## Returns
+
+- `::Array{<:Number,2}`: Complex amplitude data after propagation.
 """
 function fresnel_diffraction_double(Uin::AbstractArray{<:Number,2}, d::Real, λ::Real, lx::Real, ly::Real)
     tf = (u, v) -> exp(2im*pi*d/λ)*exp(-im*pi*d/λ*(u^2+v^2))
@@ -14,6 +26,22 @@ end
     fresnel_diffraction_single(Uin, d, λ, lx, ly)
 
 calculate the propagation light field based on the Fresnel diffraction with single Fourier transform.
+
+## Parameters
+
+- `Uin::AbstractArray{<:Number,2}`: Complex array of input complex amplitude.
+- `d::Real`: Distance to propagate in metres.
+- `λ::Real`: Wavelength of light to propagate.
+- `lx::Real`: The physical size of the input data along the x-axis.
+- `ly::Real`: The physical size of the input data along the y-axis.
+
+## Returns:
+
+    (Uout, (lxo, lyo))
+
+- `Uout::Array{<:Number,2}`: Complex amplitude data after propagation.
+- `lxo::Real`: The physical size of the diffraction data along the x-axis.
+- `lyo::Real`: The physical size of the diffraction data along the y-axis.
 """
 function fresnel_diffraction_single(Uin::AbstractArray{<:Number,2}, d::Real, λ::Real, lx::Real, ly::Real)
     qp = (x, y) -> exp(im*pi/d/λ*(x^2+y^2))