What is the Laser Cavity Lab multi-solver?

Laser Cavity Lab is a guided workflow that chains 3 individual PolySim solvers into one end-to-end analysis, piping each result into the next step.

Yes. Every step runs entirely in your browser using real numerics — no install, no account, no cloud cost. Custom or private solver packs are available as a paid service.

Physics & Quantum Pack · Multi-Solver

Laser Cavity Lab

Gain, mirror, beam. This multi-solver chains 3 solvers into a single guided workflow — run each step in order and carry the result forward.

Workflow steps

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Laser Cavity

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Laser CavityLive

gain, loss & threshold

Controls

Presets

Pump power

Cavity loss

A laser fires only when the optical gain from the pumped medium exceeds the losses of the mirror cavity. Below that threshold it merely glows like a lamp; above it, stimulated emission takes over and output rises steeply and linearly with pump power. This sharp threshold is the defining signature of laser action.

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Data Inspector

Threshold2.0

Output power1.60

Statelasing

Governing equation

P_{out} = 0.8 max (P_{pump} - P_{th}, 0) = 0.8 max (4 - 2.0, 0) = 1.60

Reading this result: Well above threshold, output climbs almost linearly with pump; the slope (~0.8 here) is the slope efficiency, and lowering cavity loss shifts the whole knee left.

Runs locally in your browser — free forever. Scale to the cloud when reality gets heavy.

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Bragg Mirror

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Bragg Mirror (DBR)Live

a mirror from interference

Controls

Presets

Layer pairs

High index n_H

Low index n_L

A distributed Bragg reflector stacks alternating quarter-wave layers of high and low index. Their reflections add up in phase over a band of wavelengths — the stopband — creating a mirror that can exceed 99.99% reflectivity, far better than metal. More layer pairs and higher index contrast deepen the reflectivity. Used in lasers, fiber gratings, and dielectric mirrors.

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Data Inspector

Peak reflectivity99.627%

Layer pairs8

Index contrast1.59

Stopband width160 nm

Governing equation

R = (\frac{n _{0} n _{H}^{2 N} - n _{s} n _{L}^{2 N}}{n _{0} n _{H}^{2 N} + n _{s} n _{L}^{2 N}})^{2} = (\frac{2. 3 ^{16} - 1.5 \cdot 1.4 5 ^{16}}{2. 3 ^{16} + 1.5 \cdot 1.4 5 ^{16}})^{2} = 99.627%

Reading this result: Each added pair multiplies the residual transmission, so reflectivity approaches 100% geometrically — a little more contrast buys many fewer layers.

Runs locally in your browser — free forever. Scale to the cloud when reality gets heavy.

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Gaussian Beam

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Gaussian BeamLive

how a laser beam spreads

Controls

Presets

Beam waist w₀ (µm)

Wavelength (nm)

A real laser beam is not a perfect ray — it narrows to a minimum waist then spreads. Within one Rayleigh range of the waist it stays roughly collimated; beyond, it diverges at an angle set by wavelength over waist size. Tighter focus means faster spreading — the fundamental diffraction trade-off behind every laser and telescope.

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Data Inspector

Rayleigh range0.012 m

Divergence4.03 mrad

Waist50 µm

Governing equation

w (z) = w_{0} 1 + (z / z_{R})^{2}, z_{R} = \frac{π w _{0}^{2}}{λ} = 12.4 mm

Reading this result: Divergence is set by λ/(π·w₀): shrinking the waist or lengthening the wavelength both make the beam spread faster — the core diffraction trade-off.

Runs locally in your browser — free forever. Scale to the cloud when reality gets heavy.

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Frequently asked questions

What is the Laser Cavity Lab multi-solver?: Laser Cavity Lab is a guided workflow that chains 3 individual PolySim solvers into one end-to-end analysis, piping each result into the next step.
Is it free to use?: Yes. Every step runs entirely in your browser using real numerics — no install, no account, no cloud cost. Custom or private solver packs are available as a paid service.