What optical power range and Numerical Aperture (NA) does a Variable Focus Moiré Lens provide?

n₁ = (sinc (^θ⁄₂))²  (1)

Provided that the photolithographic processing unit of the DOE surface is in the wavelength range (which is true outside of the UV range), the optical power (D) of a Variable Focus Moiré lens can be calculated as follows:

D = ^θ⁄_Aπ  (2)

Here θ, stands for the current twist angle of the DOEs and A denotes the clear aperture of the lens.

Equation 1 shows that the diffraction efficiency of the Variable Focus Moiré lens for a twist angle of ±90º (θ = ±^π⁄₂) is higher than 80%. For this lens with an aperture of the optical power range is as follows:

D = ±¹⁄_2A = ±25 Dpt

This means that the optical power of the Variable Focus Moiré lens is inversely proportional to the aperture. The NA has a constant value throughout the modulation of its optical power (NA = 0.24 in example described above).