Choosing a Light Source

There is such a wide choice of Scientific research and development light sources available that it may be difficult to select the best system for your application. Figure 1 shows the spectral ranges of Oriel light sources.

Spectral ranges of Oriel Light Sources.

Figure 1. Spectral ranges of Oriel Light Sources.

The Requirements

To determine the type of light source needed it is important to understand if one needs a continuous or pulsed light source, what wavelengths or wavelength regions are required and what output power is required.

CW or Pulsed

Oriel instruments has a selection of pulsed sources such as µs Xenon flashlamps, pulsed deuterium lamps and ns pulse Nitrogen and Dye Lasers and a large selection of UV to Far-IR continuous sources.

Wavelength Range

Figure 1 shows the usable wavelength range for each of the light source families. In case the wavelength range needed is known the choice can be narrowed the choice down to two.

Output Power

The spectral irradiance curves for the lamps and the tutorial on Calculating the Output Power From a Source helps in calculating the output power from an Oriel Source.

Product Summary

The products of Oriel Instruments are described below:

CW Sources

CW Sources include the following:

  • DC Deuterium Lamps: 160 to 400nm
    • Source with lowest wavelength output
    • Negligible VIS-IR output
    • Preferred source for UV spectroscopy because it ensures best S/N for UV measurements
    • Smooth continuous UV specturm
  • DC Arc Lamps: 200 to 2500nm
    • Produce highest irradiance of small targets
    • Have small, high radiance arc
    • Intense UV output
    • Can simulate solar spectrum
  • Quartz Tungsten Halogen Lamps: 240 to 2700nm
    • Have excellent stability
    • Easy and inexpensive to operate
    • Ideal for radiometric and photometric applications
    • High total visible output
  • IR Elements: 700nm to 40µm
    • Excellent for IR spectroscopy
    • Different models available to cover various IR wavelength regions
    • Long life
  • Helium Neon Lasers: 632.8nm
    • Clean TEM00 mode
    • Low cost
    • Visible output is ideally suited for alignment
  • Solid State Lasers: 532nm
    • 10mW and 50mW output powers
    • Low beam divergence
    • 0.05nm linewidth

Pulsed Sources

Pulsed sources include the following:

  • Pulsed Deuterium Lamps: 180 to 400nm
    • Higher peak UV power than DC lamps
    • Smooth UV continuum
    • Extended life of UV sensitive optical components
    • Low cost mounts available
  • Pulsed Xenon Arc Lamps: 180 to 2500nm
    • High peak power
    • Broadband spectral output
    • |js pulses for transient studies
  • Nitrogen Lasers: 337.1nm
    • Short, ns, UV pulses
    • High radiance
    • Fiber compatible
  • UV Tunable Laser System: 220 to 320nm
    • <3 ns pulsewidth
    • 6 µJ/pulse at 10 Hz
    • Ideal for Laser Induced Fluorescence (LIF) studies
    • Superior beam quality
  • CO2 Laser: 10.6 pm
    • 10µJ, 125 ns pulses @ 10.6 jm
    • 40kW peak power
    • Sealed and air cooled plasma cartridge

6035 Hg(Ar) Lamp in 63670 Holder with 6047 Power Supply.

Oriel offers a wide range of sources for use as calibration standards. They are classified into two families, Spectral Calibration Lamps and Calibrated Irradiance Lamps.

Spectral Calibration Lamps

  • Produce narrow spectral lines
  • Used for wavelength calibration of spectral instruments (i.e. monochromators, spectrographs, spectral radiometers)

Calibrated Irradiance Sources

  • Broadband, continuum sources.
  • Carefully characterized spectral irradiance, traceable to NIST.
  • Used as transfer standards to calibrate detection systems.
  • Also used to cross-calibrate other lamps, or to irradiate a sample with a known power density.
  • Custom Calibrations; Oriel frequently provides custom spectral calibration services in the 200-2400 nm range and is now extending these services to IR with the use of MIR 8000™ FT-IR.

Custom Calibrations

Oriel frequently provides custom spectral calibration services in the 200-2400nm range and is now extending these services to the IR, with the use of our new MIR 8000™ FT-IR.

Choosing a Calibration Package

Even though the two lamp families have separate purposes yet are used together to completely calibrate a system. To achieve the highest accuracy, a spectral line lamp for wavelength calibration can be used then a calibrated irradiance lamp with a stabilized, radiometric power supply for power level calibration. The calibrated deuterium source can be used for the 200 to 400 nm range, and a calibrated quartz tungsten halogen source for the 250 to 2400 nm range is used. If utmost accuracy is not crucial, the Hg(Ar) spectral calibration lamps may be used for spectral calibration and to determine relative power level calibration.


The most important figure of merit for a calibration source is its accuracy. Accuracy is often stated using uncertainties which describe any possible variation from the true values. For some of the lamps you will find uncertainty values, use these values as a comparison to other products and as a guide for the error analysis of your own system.

Spectral Calibration Lamps

The spectral calibration lamp is the most precise and economic method of wavelength calibration. Oriel Instruments offers lamps to cover wavelengths from below 185 to over 2.5µm.

Wavelength Uncertainty

When electrons residing in some excited energy level fall to a more stable energy level these lamps emit line spectra. The levels are distinct states defined by the rest masses of atomic particles and the quantized charge of those particles. Hence a given chemical element may only emit specific wavelength radiation. Since this emission and excitation is a documented and well understood process the wavelengths are considered to be absolute and have been documented extensively. Environmental conditions such as dramatic temperature changes and the existence of strong electric or magnetic fields may cause a small shift in the location of some spectral lines.

About Oriel Instruments

Oriel Instruments, a Newport Corporation brand, was founded in 1969 and quickly gained a reputation as an innovative supplier of products for the making and measuring of light. Today, the Oriel brand represents leading instruments, such as light sources covering a broad range from UV to IR, pulsed or continuous, and low to high power.

Oriel also offers monochromators and spectrographs as well as flexible FT-IR spectrometers, which make it easy for users across many industries to build instruments for specific applications. Oriel is also a leader in the area of Photovoltaics with its offering of solar simulators that allow you to simulate hours of solar radiation in minutes. Oriel continues to bring innovative products and solutions to Newport customers around the world.


This information has been sourced, reviewed and adapted from materials provided by Oriel Instruments.

For more information on this source, please visit Oriel Instruments.


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