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Laser Pulse Calculator

Essential calculations for ultrafast laser labs: time-bandwidth product, peak power from average power, and pulse broadening through dispersive media.

Time-Bandwidth Product

Pulse shape
Input (edit either)

Time-bandwidth product. Δt · Δν ≥ TBP. Gaussian: 0.4413, sech²: 0.3148, Lorentzian: 0.2206. Δν = c Δλ/λ².

Results

Transform-limited Δt
Frequency bandwidth Δν
Optical cycles
TBP (actual / minimum)
Export

Peak Power

Pulse shape
Parameters

Peak power. E = Pavg/frep,   Ppeak = k E/Δt. k: Gaussian 0.94, sech² 0.88, rect 1.0.

Results

Pulse energy
Peak power
Duty cycle
Peak / Average ratio

GDD Pulse Broadening

Input pulse
Material

GDD broadening (Gaussian). Δtout = Δtin √(1 + (4 ln2 · GDD/Δtin²)²). GDD = GVD × L × passes.

Results

Total GDD
Output Δt
Broadening factor

Gaussian Beam

Parameters
Beam quality factor. M^2 = 1 is a diffraction-limited Gaussian; larger values increase divergence and focused spot size.
Waist size (edit any)
Evaluate at distance

Gaussian beam. zR = πw0²/(M²λ),   w(z) = w0√(1+(z/zR)²),   θ = M²λ/(πw0).

Results

Rayleigh range zR
Divergence θ (half-angle)
Confocal parameter 2zR
w(z) at selected z

Focus & Fluence

Beam before lens
Focusing optic
Pulse

Focus. w0 ≈ M² λ f/(π win). I = Ppeak/(πw0²). F = E/(πw0²).

Results

Spot radius w0
Spot diameter 2w0
Peak intensity
Fluence
Rayleigh range zR
Depth of focus 2zR

Chirp & Compressor

Measured pulse
Transform limit
Compressor material

Chirp compensation. GDD = ±Δtin √((Δtactual/ΔtTL)²−1)/(4 ln2). L = |GDD|/GVD. Sign of GDD tells you if pulse has positive or negative chirp.

Results

Chirp ratio Δt/ΔtTL
GDD on the pulse
Compensating GDD
Material needed

Nonlinear Conversion

Process
Input wavelengths

SHG. ω + ω → 2ω. λout = λ/2.

Results

Output wavelength
Output energy

Spectral Brightness

Source
Spectrum
Beam quality

Spectral brightness. B = P/(Δλ · A · Ω). For Gaussian beam: A·Ω = M4λ², so B = P/(M4λ²Δλ). Defaults from Elu et al., Nature Photon. (2021).

Results

Pulse energy
Peak power
Avg spectral density
Peak spectral density
Avg spectral brightness
Peak spectral brightness

Beam Modes

Mode family
LG indices
Beam

LGℓ,p. Modes with orbital angular momentum ℓℏ per photon and p radial nodes. Donut profile for ℓ≠0.

Intensity profile

Mode label
OAM per photon