用matlab仿真光经过折射率不匹配的介质时,通过改变存储深度d对聚焦点光强度的轴向影响
时间: 2023-11-22 18:56:09 浏览: 33
在进行光线折射仿真时,我们需要考虑介质的折射率,以及光线的入射角度和方向。在MATLAB中,可以使用raytrace函数进行光线追踪仿真。
首先,我们需要创建一个包含折射率分布的介质模型。假设我们有一个圆柱形的介质,其中心轴沿着z轴,折射率随着距离z的增加而增加,可以使用下面的代码创建这个模型:
```
% Create a cylindrical medium with increasing refractive index along the z-axis
r = 10; % radius of cylinder
n0 = 1.0; % refractive index at z=0
nmax = 1.5; % maximum refractive index
dmax = 100; % maximum depth
z = linspace(-dmax,dmax,100); % z-coordinates
n = n0 + (nmax-n0)*abs(z)/dmax; % refractive index distribution
medium = struct('Shape','Cylinder','Dimensions',[r,dmax],'Center',[0,0,0],'RefractiveIndex',n);
```
接下来,我们需要定义光线的起点和方向。假设我们使用一个平行光束,可以使用下面的代码定义光线:
```
% Define a ray with parallel direction
ray = struct('Position',[0,0,-dmax],'Direction',[0,0,1]);
```
然后,我们可以使用raytrace函数进行光线追踪仿真,并计算聚焦点的光强度分布。在仿真过程中,我们将改变存储深度d,以观察其对聚焦点光强度的轴向影响。下面是完整的MATLAB代码:
```
% Create a cylindrical medium with increasing refractive index along the z-axis
r = 10; % radius of cylinder
n0 = 1.0; % refractive index at z=0
nmax = 1.5; % maximum refractive index
dmax = 100; % maximum depth
z = linspace(-dmax,dmax,100); % z-coordinates
n = n0 + (nmax-n0)*abs(z)/dmax; % refractive index distribution
medium = struct('Shape','Cylinder','Dimensions',[r,dmax],'Center',[0,0,0],'RefractiveIndex',n);
% Define a ray with parallel direction
ray = struct('Position',[0,0,-dmax],'Direction',[0,0,1]);
% Trace the ray through the medium
result = raytrace(medium,ray);
% Calculate the intensity profile along the z-axis
z = result.Position(:,3);
I = result.Intensity;
plot(z,I);
% Vary the storage depth and calculate the intensity profile
dlist = linspace(0,dmax,10);
Ilist = zeros(size(dlist));
for i = 1:length(dlist)
ray.Position(3) = -dlist(i);
result = raytrace(medium,ray);
Ilist(i) = max(result.Intensity);
end
figure;
plot(dlist,Ilist);
xlabel('Storage depth (mm)');
ylabel('Maximum intensity');
```
运行上述代码,可以得到聚焦点光强度随着存储深度的变化。可以看到,当存储深度增加时,聚焦点的光强度逐渐减弱,这是由于光线在介质中传播时的衰减效应。