Calculators
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Power Technology, Inc.
Laser Toolkit
Fifteen engineering calculators for laser specification and integration, including beam geometry, fiber coupling, wavelength, pulse timing, and unit conversions.
Wavelength
Wavelength Viewer
Visualize approximate perceived color and photopic response, with spectral region, frequency, photon energy, wavenumber, and detection guidance.
- Photopic response V(λ)
- 89% of peak
- Region
- Visible
- Frequency
- 563.5THz
- Photon energy
- 2.331eV
- Wavenumber
- 18,797cm⁻¹
Catalog wavelength: 532 nm
Beam & optics
Beam spread & irradiance
Calculate beam diameter and average or peak irradiance at a specified distance.
- Beam diameter
- —
- Spot area
- —
- Average irradiance
- —
- Peak irradiance
- —
Far-field approximation: diameter grows linearly as d₀ + θz. For an ideal Gaussian spatial profile, on-axis peak irradiance is twice the area-average value.
Beam & optics
Divergence from measurements
Calculate beam divergence from diameters measured at the aperture and a second axial position.
- Full divergence
- —
- In degrees
- —
- Half-angle
- —
Measure both diameters to the same convention — 1/e² or FWHM, but not one of each.
Beam & optics
Fan angle for line lasers
The minimum fan angle needed to cover a target width at a given distance.
- Minimum fan angle
- —
- Width at 1 m
- —
Line lasers are specified by fan angle. Select the next available angle at or above the calculated minimum; excess coverage can be masked.
Wavelength
Wavelength ↔ frequency
Convert between wavelength, optical frequency, and photon energy.
- Photon energy
- —
- Period
- —
Edit either field and the other follows. Uses c = 299,792,458 m/s in vacuum.
Wavelength
Wavenumber ↔ wavelength
Convert between reciprocal centimetres and wavelength in nanometres.
- Relationship
- λnm = 10⁷ ÷ ν̃
For a Raman shift, subtract the shift in cm⁻¹ from the excitation wavenumber, then convert the result back to nanometres.
Pulse & power
Duty factor
Calculate the fraction of each pulse period during which the source emits.
- Duty factor
- —
- Pulse period
- —
- Off time
- —
Duty factor rises with either a longer pulse or a faster repetition rate, and falls as the period lengthens.
Pulse & power
Pulse energy & average power
Calculate pulse energy, average power, and duty factor from peak power, pulse width, and repetition rate.
- Energy per pulse
- —
- Average power
- —
- Duty factor
- —
Pulse width is treated as full duration for rectangular pulses and intensity FWHM for Gaussian pulses.
Assumptions & formulas
Peak power must describe the actual temporal peak. A measured pulse waveform should be integrated when its shape is not well represented by either option.
Conversions
Optical length units
Convert among length units commonly used in optics and spectroscopy.
- Relationship
- 1 Å = 0.1 nm
Edit any field and the other two follow. Older spectroscopy literature quotes lines in Ångströms — 6328 Å is the HeNe red line.
Conversions
Temperature
Convert operating and storage temperatures among Celsius, Fahrenheit, and kelvin.
- Relationship
- °F = °C × 9/5 + 32
Laser-diode wavelength generally varies with junction temperature; values specified at 25 °C should not be assumed across the full operating range.
Beam & optics New
Gaussian propagation & focus
Model a Gaussian-like beam in free space or estimate the spot formed by a lens. Each section works independently.
Free-space propagation
- Beam diameter X × Y
- —
- Rayleigh range X / Y
- —
- Full divergence X / Y
- —
Lens focus — uses wavelength and M² above
- Focused diameter X × Y
- —
- Confocal range X / Y
- —
- Approx. lens NA X / Y
- —
Clear aperture is optional. Enter it to check for possible beam clipping.
Assumptions & formulas
Inputs are full 1/e² intensity diameters of a Gaussian-like beam. X and Y are solved independently. This calculator provides engineering estimates; it is not an ISO-compliant M² measurement.
zR = πw₀²/(M²λ); w(z) = w₀√[1+(z/zR)²] θ(full) = 2M²λ/(πw₀) wfocus ≈ M²λf/(πwlens); confocal range = 2πwfocus²/(M²λ)ISO 11146 uses second-moment beam widths and separate treatment for general astigmatic beams. Use an M² value obtained from a validated measurement; entering 1 assumes an ideal Gaussian. ISO 11146-1 overview.
Beam & optics New
Fiber NA & acceptance angle
Calculate the acceptance cone of a step-index fiber and optionally check its normalized frequency.
- Numerical aperture
- —
- Acceptance half / full angle
- —
- Approximate f-number
- —
- V-number
- —
The V-number output requires both core diameter and wavelength.
Assumptions & formulas
Step-index, meridional-ray approximation. Material indices must be entered at the operating wavelength.
NA = √(n₁²−n₂²); θa = asin(NA/n₀) f/# ≈ 1/(2NA); V = (2πa/λ)NAFor a conventional step-index fiber, V < 2.405 is the usual single-mode cutoff criterion; actual coupling also depends on mode-field diameter, alignment and beam quality.
Conversions New
Optical loss & power budget
Combine component losses to estimate delivered power. Detector responsivity is optional.
- Delivered power
- —
- Total transmission
- —
- Total loss
- —
- Detector current
- —
Enter responsivity at the operating wavelength to estimate ideal photocurrent.
Assumptions & formulas
Losses are treated as independent scalar power losses. Polarization, back-reflection, detector saturation, coupling alignment and wavelength dependence are not modeled.
Pulse & power New
Pulse fluence & peak irradiance
Calculate from either pulse energy or peak power while accounting for temporal and spatial pulse shape.
- Peak fluence
- —
- Area-average fluence
- —
- Pulse energy
- —
- Peak power
- —
- Peak irradiance
- —
- Average power
- —
For Gaussian spatial mode, diameters are full 1/e² intensity widths.
Assumptions & formulas
Rectangular temporal pulse: E = Ppeakτ. Gaussian temporal pulse with intensity FWHM τ: E = Ppeakτ√π/[2√(ln2)] ≈ 1.06447Ppeakτ.
A = πDxDy/4; Favg = E/A Gaussian spatial peak = 2 × area average; top-hat peak = area average Paverage = E × repetition rateReal pulses and diode beams can depart from these ideal profiles. NIST notes that accurate peak-power work depends on resolving the actual waveform and detector impulse response. NIST SP 250-64.
Beam & optics New
Refraction & window displacement
Solve a single interface, then optionally estimate lateral shift through a parallel window.
- Refracted angle
- —
- Brewster angle
- —
- Critical angle
- —
- Lateral displacement
- —
- Path inside window
- —
Angles are measured from the surface normal. Indices should correspond to the operating wavelength.
Assumptions & formulas
The window calculation assumes plane, parallel surfaces and isotropic, nonabsorbing media. Coatings, wedge, dispersion and polarization-dependent Fresnel losses are not included.
No matching tools. Suggested searches: divergence, duty factor, joules, or angstrom.
Results support preliminary engineering estimates and comparisons; they do not determine laser-safety classification. For hazard distances, eyewear selection, and exposure limits, apply the relevant IEC 60825 and ANSI Z136 requirements and consult a qualified laser-safety professional.
Divergence Calculation
| Distance [m]: | |
| Laser: | |
| Power [mW]: | |
| Divergence [mrad]: | |
| Diameter at aperture [mm]: | |
| Beam diameter after m: | mm |
| Area of laser point after m: | mm2 |
| Laser intensity of uniform beam after m: | mW/mm2 |
Find a laser beam's divergence
| Specifications: | |
| Distance from Laser Aperture -> Projection surface [m]: | |
| Beam Waist Diameter at Laser Aperture [mm]: | |
| Laser spot diameter at the projection surface [mm]: | |
| The Full Divergence of the laser system is: |
| 0.00 mrad |
Calculating nanometers from wavenumber
Converting angstroms to nanometers
To convert from angstroms to nanometers, use the following equation:
1 angstrom = 0.1 nanometer. Or use the tool below.
Converting fahrenheit to celsius
To convert from fahrenheit to celsius, use the following equation:
32° Fahrenheit = 0° Celsius. Or use the tool below.
Converting watts to joules
Power is measured in Watts, named after James Watt (1736-1819). Joules (named after James Prescott Joule, 1818-1889) are units of energy. Use the following equation to convert from Watts to Joules.
1 Watt = 1 Joule per second of power
Fan Angle Calculator
To achieve your desired projection, select a minimum fan angle of: degrees | ||||
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Meters Centimeters Feet Inches |  |
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| Meters Centimeters Feet Inches | ||||
Converting wavelength to frequency
You can use the following equation to convert wavelength to frequency:
v (Hz) = 2.998 x 1017 / wavelength (nm).
Calculating duty factor
Duty factor (also known as duty cycle) is the ratio of pulse duration to pulse period. Duty factor (Df) is calculated as follows.
Df = pulse duration (sec) / pulse repetition period (sec)
Multiply the result by 100 to get your answer as a percentage.
Please note that as pulse repetition frequency increases, duty factor increases. As pulse repetition period increases, duty factor decreases. As pulse duration increases, duty factor increases.
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