Optical Path Designer · IAMS Yb Lab

MissAlign

Enter the Simulator →
No install · Runs entirely in your browser
Features

What the Simulator Does

Everything you would do at the real table — laid out, traced, and measured on screen first.

01

Drag-and-Drop Path Design

Place lasers, mirrors, beamsplitters, modulators and fiber ports on a virtual optical bench, snapped to a 25 mm hole grid. Add breadboards, lock them so their optics ride along, group components to move and mirror them as one — and lay out the nanofiber-MOT chamber with its real keep-out geometry.

02

Real-Time Beam Tracing

Beams propagate live along the path. Every component updates the polarization state via Jones matrices and recalculates power splitting — turn a waveplate and watch the PBS ratio change instantly. AOM orders, EOM sidebands and fiber channels are all traced together.

03

Astigmatic Gaussian Optics

Both transverse axes are tracked independently, so cylindrical lenses, sheet beams and elliptical sources are real physics rather than an approximation. The beam radius follows from the q parameter and ABCD matrices on each axis, with per-axis waists, Rayleigh ranges and ellipticity reported everywhere.

04

w(z) Caustic Analysis

Pick which light to plot — laser, fiber output or periscope — trim the range to any two optics, and read the envelope of both axes along the path. A probe cursor links the plot to the bench in both directions, so any point on the curve maps to a physical plane on the table. Export the trace as CSV.

05

Fiber Coupling, Honestly

Fiber ports carry an optional integrated collimator, and coupling efficiency is computed per axis — so an elliptical beam is told the truth: no single spherical lens fixes both axes. Presets, NA ↔ mode-field controls, channel pairing, fiber chains, and a one-click auto-align that scores by real re-tracing.

06

Out-of-Plane Routing

Periscopes take the beam off the table and bring it back — including the 90° turn that exchanges the two transverse axes. The vertical run and the whole far side of the path are stitched into one continuous w(z) curve, with the height above the bench read out.

07

Sub-Hole Fine Alignment

Alignment is not a 25 mm grid operation. Every relevant optic gets nudges along the beam, across it and in angle, down to 0.01 mm — plus typed distances, a “z on beam” path-length readout, and centre-to-centre separation for pairs.

08

Figures, 3D and Saving

One click exports a publication-quality line-art schematic as SVG or PNG, with standard symbols and labels that dodge the beams. Switch to a 3D view of the whole table, export CAD, and save layouts to a portable JSON file — with light and dark themes for reports.

Component Physics

Components & How They Work

Every element in the simulator maps to real hardware on the table — its behavior is driven by the underlying physics, not by a sprite.

Laser

Laser Source

Where every path begins. Stimulated emission produces coherent light, emitted as a near-ideal TEM₀₀ Gaussian beam.

w(z) = w₀√(1 + (zzR)²),zR =πw₀²λ
Stimulated emission · Gaussian mode w(z) · λ sets all diffraction downstream
Mirror · HR / OC / Dichroic

Mirrors

Dielectric multilayer coatings reflect by interference: HR mirrors reach R>99.9%, output couplers transmit a controlled fraction, and dichroics reflect or transmit by wavelength.

θinc = θrefl,R(λ) + T(λ) = 1
Thin-film interference · angle in = angle out · R(λ) set by coating design
V-Mirror · Periscope

Out-of-Plane Fold

A 45° fold that sends the beam out of the board plane. Two of them on a channel form a periscope: the beam runs vertically between them and re-enters the plane at the mate, carrying its polarization, frequency history and accumulated path length. One alone can retro-reflect — a MOT vertical arm.

L → L + Lv,Δφazimuth = 90°⇒(w∥, w⊥) → (w⊥, w∥)
Two 45° folds · adds the vertical run to z · a 90° turn exchanges the transverse axes
PBS

Polarizing Beamsplitter

A multilayer coating on the diagonal transmits p-polarized light and reflects s-polarized light, splitting one beam into two by polarization. Paired with a half-wave plate, it becomes a continuously tunable power divider.

Pt = P₀ cos²φ,Pr = P₀ sin²φ
Polarization-selective reflection · T_p ≈ 1, R_s ≈ 1 · split ∝ cos² / sin²
Beamsplitter · Plate / Cube

Beamsplitters

A partially reflective coating divides the beam at a fixed ratio (50:50, 90:10, …), independent of polarization — the workhorse of pick-offs, monitoring, and interferometers.

Pr = R·P₀,Pt = (1 − R)·P₀
Partial reflection · R + T = 1 (lossless) · ratio fixed by coating
λ/2 Waveplate

Half-Wave Plate

A birefringent crystal delays one polarization component by π relative to the other: linear polarization is mirrored about the fast axis, so rotating the plate by θ rotates the polarization by 2θ.

Γ =2π(ne − no)dλ= π,α′ = 2θ − α
Birefringent retardance Γ = π · rotation = 2θ · + PBS = tunable splitter
λ/4 Waveplate

Quarter-Wave Plate

A π/2 retardance: linear polarization at 45° becomes circular, and vice versa. In double pass (through, reflect, through again) it acts as a half-wave plate — the classic optical-isolation trick.

Γ =π2,Ecirc =x̂ ± iŷ√2
Γ = π/2 · linear ↔ circular · double pass = λ/2
Lens

Lens

Refraction reshapes the wavefront to focus or collimate the beam. For a Gaussian beam, the new waist size and position follow from transforming the q parameter with the ABCD matrix — not from the geometric image point.

1f=1so+1si,q′ =q1 − q/f
Thin lens ABCD = [1 0; −1/f 1] · new w₀′ and position from q′
Cylindrical Lens

Cylindrical Lens

Curved on one meridian only, so it focuses one transverse axis and leaves the other untouched — the element that makes a beam astigmatic on purpose. A crossed pair with different focal lengths turns an elliptical beam into a round one; a crossed pair with equal focal lengths is just a spherical lens.

q′∥ =q∥1 − q∥/f,q′⊥ = q⊥
Power on one meridian · ABCD applied per axis · pairs circularise an ellipse
Prism

Dispersive Prism

Two refractions at tilted faces, each set by Snell's law with an index that depends on wavelength, so every colour leaves at its own angle. The beam is traced through the real triangle (Thorlabs PS850, F2 glass) at n(λ) from the Sellmeier equation; at minimum deviation the path is symmetric and the beam width is preserved.

δmin = 2 arcsin(n sinA2)− A
Sellmeier n(λ) · refraction at both faces · TIR handled · F2: 399 vs 680 nm separate by 3.9°
Grating

Diffraction Grating

Periodic grooves make the reflected wavelets interfere: they add up only in the directions where neighbouring grooves differ by a whole number of wavelengths. Each order leaves at its own angle per wavelength — the grating equation — so a grating is a spectrometer and, in the Littrow geometry, the wavelength-selective mirror of an external-cavity diode laser. Modelled as the Thorlabs GH13-24U (2400 lines/mm).

d (sin α + sin β) = m λ
One beam per order · evanescent orders skipped · Littrow β = α · dβ/dλ = m / (d cos β)
AOM

Acousto-Optic Modulator

An RF-driven sound wave creates a traveling refractive-index grating inside a crystal. The beam Bragg-diffracts off it: the first order is deflected and frequency-shifted by ±f_RF — the workhorse for fast switching, frequency scans, and power stabilization.

sinθB =λ2Λ,f′ = f ± m·fRF
Bragg diffraction sinθ_B = λ/2Λ · 1st order shifted f ± f_RF · switching ~ns–µs
EOM

Electro-Optic Modulator

Based on the Pockels effect: an applied electric field changes the crystal's refractive index linearly, modulating the optical phase at high speed and adding ±f_mod sidebands to the spectrum — the heart of PDH laser locking.

Δφ = πVVπ,Δn = −n³rE2
Pockels effect Δn ∝ E · phase φ(t)=β sin(2πf t) · generates sidebands
Shutter

Mechanical Shutter

A mechanical blade blocks the path completely — extremely high extinction, but slow (millisecond scale). It works in tandem with the AOM: the AOM is fast, the shutter closes clean.

ER =PopenPclosed,T(t) ∈ {0, 1}
Mechanical blocking · switching ~ms · extinction ≫ AOM
Iris

Iris

An aperture that passes the orders you choose and blocks the rest. Because an AOM separates its diffraction orders by angle, they are spatially resolved a short distance downstream — so a stopped-down aperture is how you actually pick one order and dump the others.

Δθ ≈λΛper order,T = 1 − e−2a²/w²
Angular order separation · clips by radius · Gaussian truncation T(a/w)
Fiber Coupling

Fiber Coupling

Sending a free-space beam into a single-mode fiber requires matching the incoming Gaussian waist to the fiber's mode field — and the efficiency is brutally sensitive to alignment. The most misalign-prone spot on any table.

η =|∫ Ein Ef* dA|²∫|Ein|²dA · ∫|Ef|²dA
Mode matching · η = |⟨E_in|E_fiber⟩|² · sensitive to offset & tilt
Beam Dump · Power Meter

Beam Dump & Power Meter

Where paths end: a beam dump safely absorbs unwanted light, while a power meter reads the optical power via photodetection — the readout you use in the simulator to verify every splitting ratio.

I = ℛ·P,ℛ =ηeλhc
Absorptive dissipation · photocurrent ∝ power · readout on every branch
Camera

Imaging Sensor

Terminates the beam and reports what a beam profiler would actually show you: the spot size in pixels on each axis, how much of the sensor it fills, and whether it is clipped. An elliptical beam can overrun the short side while the long side is still comfortable, so both axes are quoted separately.

Npx =2wp,fill =2w∥LW,2w⊥LH
Pixel-pitch sampling · per-axis fill and clipping · ⌀ = 2w on both axes
Physics Engine

Under the Hood

Behind every beam on screen, two standard optical formalisms are doing the math.

Gaussian Beam · ABCD
1q = 1R(z) − i λπw²(z)
q′ = Aq + BCq + D

A Gaussian beam's radius and wavefront curvature are packed into a single complex q parameter. Every stretch of free space, lens, or curved mirror applies its ABCD matrix to q. The simulator chains these matrices along the full path and draws the beam envelope (caustic) live — including the waist w₀ and the Rayleigh range zR = πw₀²λ.

Polarization · Jones Calculus
Eout= Mn ··· M₂ M₁ · Ein
Mλ/2(θ)= R(−θ) diag(1, eiπ) R(θ)

The polarization state is a two-component complex vector (Jones vector); each waveplate, PBS, and mirror is a 2×2 Jones matrix. Every component the beam passes through multiplies the state once — so as you rotate a half-wave plate, the two PBS outputs trade power as cos²2θ / sin²2θ, exactly as on the real table.

Ready to align?

Open the virtual bench and place your first mirror.

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