easiest lens making method :
I found 3829193 at google patents. As you see , its a early 70s patent.
It is the most easy way of lens making description.
You buy some acrylate gel , load it with potassium bichromate , some gels carry good amount of other liquids as we see at dye transfer method.
Than you put it on a crt or lcd or plasma monitor.
You expose the gel with light intensity changing image.
The more the gel exposed to the light , it will be thicker
The less the gel exposed to the light , it will be thinner
With changing the chemicals and contact printed images , you can make zernike phase plates , aspherical shapes etc.
YOU HAVE TO BE VERY CAREFUL WITH POTASSIUM BICHROMATE , IT MAKES BIRTH DEFECTS AT CHILDREN.
There is many other chemicals , photo curable acrylics at the market and google science research.
Mustafa Umut Sarac