Modulators

Phase and amplitude modulation components.

Overview

The Modulators module provides components that modify the amplitude and phase of optical fields through masks, diffractive elements, and reflective surfaces.

Examples

Phase Modulation

using FluxOptics

xv, yv = spatial_vectors(128, 128, 2.0, 2.0)
u = ScalarField(Gaussian(50.0)(xv, yv), (2.0, 2.0), 1.064)

# Parabolic phase (lens-like)
phase_lens = Phase(u, (x, y) -> π/(1000^2) * (x^2 + y^2))

istrainable(phase_lens)  # false (static)

false

# Trainable phase mask for optimization
phase_opt = Phase(u, (x, y) -> 0.0; trainable=true, buffered=true)

(istrainable(phase_opt), isbuffered(phase_opt))

(true, true)

Amplitude Modulation

# Circular aperture
radius = 80.0
aperture = Mask(u, (x, y) -> sqrt(x^2 + y^2) < radius ? 1.0 : 0.0)

# Apply to field
u_masked = propagate(u, aperture, Forward)

# Check power reduction
(power(u)[], power(u_masked)[])

(0.9999993933337604, 0.9940104642476999)

# Gaussian apodization (smooth amplitude taper)
w0 = 100.0
apodization = Mask(u, (x, y) -> exp(-(x^2 + y^2)/(2*w0^2)))

u_apodized = propagate(u, apodization, Forward)

power(u_apodized)[]

0.8888887899356903

Diffractive Elements

# Sinusoidal grating
Δn = 0.5  # Refractive index difference
period = 50.0  # Grating period
grating = TeaDOE(u, Δn, (x, y) -> 0.5 * sin(2π * x / period))

# Trainable DOE for beam shaping
doe_opt = TeaDOE(u, 0.5, (x, y) -> 0.0; trainable=true, buffered=true)

istrainable(doe_opt)

true

Using in Systems

# Combine multiple modulators
source = ScalarSource(u)
phase = Phase(u, (x, y) -> 0.01 * (x^2 + y^2))
aperture = Mask(u, (x, y) -> sqrt(x^2 + y^2) < 60.0 ? 1.0 : 0.0)
prop = ASProp(u, 1000.0)

system = source |> phase |> aperture |> prop

result = system()
power(result.out)[]