Calculators
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Power Technology, Inc.
Laser Toolkit
Ten working tools for the numbers that come up when you're specifying a laser — beam geometry, wavelength, pulse timing, and unit conversions.
Wavelength
Wavelength Viewer
What a wavelength actually looks like, how bright the eye finds it, and how the invisible bands are detected in practice.
- Eye response V(λ)
- 89% of peak
- Region
- Visible
- Frequency
- 563.5THz
- Photon energy
- 2.331eV
- Wavenumber
- 18,797cm⁻¹
532 nm is a stocked line
Beam & optics
Beam spread & irradiance
How wide the beam gets at a distance, and how much power lands per mm².
- Beam diameter
- —
- Spot area
- —
- Average irradiance
- —
- Peak irradiance
- —
Far-field approximation: diameter grows linearly as d₀ + θz. Peak assumes a Gaussian profile, which runs 2× the average — worth using for damage-threshold work.
Beam & optics
Divergence from measurements
Work backwards from two measured diameters to the divergence of a beam.
- 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, so round up to the next available option — a slightly wide line can be masked, a narrow one can't be stretched.
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
The spectroscopist's unit. Convert cm⁻¹ to nanometres and back.
- 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
The fraction of time a pulsed laser is actually emitting.
- 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
Ties peak power, pulse width, and rep rate to the energy in each pulse.
- Energy per pulse
- —
- Average power
- —
- Duty factor
- —
One watt is one joule per second, so average power is simply the energy in each pulse multiplied by how many arrive per second.
Conversions
Optical length units
Ångströms, nanometres and microns — the three scales optics papers mix.
- 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
For reading operating and storage ranges off a datasheet.
- Relationship
- °F = °C × 9/5 + 32
Diode wavelength drifts with junction temperature, so a spec quoted at 25 °C won't hold at the top of the operating range.
No tool matches that. Try “divergence”, “duty”, “joules” or “angstrom”.
Results are for planning and comparison, not for laser-safety classification. For hazard distances, eyewear selection, or exposure limits, work from IEC 60825 / ANSI Z136 or talk to us.
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 | ||||
|
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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