We offer various sources for use as calibration standards. We group them into two families:
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.
Spectral Calibration Lamps
Produce narrow spectral lines
Used for wavelength calibration of spectral instruments (i.e. monochromators, spectrographs, spectral radiometers)
We frequently provide custom spectral calibration services in the 200-2400 nm range and can extend these services to the IR, with our MIR 8025TM FT-IR. Please contact us if you require calibration services.
Choosing a Calibration Package
Although the two lamp families (Calibrated Irradiance Sources and Spectral Calibration Lamps) have decidedly separate purposes, they are often used together to completely calibrate a system. To achieve the highest accuracy, we suggest you use a spectral line lamp for wavelength calibration, then a calibrated irradiance lamp with a stabilized, radiometric power supply for power level calibration. Use the calibrated deuterium source for the 200 to 400 nm range, and a calibrated quartz tungsten halogen source for the 250 to 2400 nm range. If utmost accuracy is not crucial, our 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 that describe any possible variation from the true values. For some of our 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 most accurate and economical method of wavelength calibration is the spectral calibration lamp. We offer lamps to cover wavelengths from below 185 nm to over 2.5 µm. Be sure to check out our popular battery powered Hg(Ar) calibration lamp, for the utmost in ease of use and portability!
These lamps emit line spectra when electrons residing in some excited energy level fall to a more stable energy level. The levels themselves are distinct states defined by the rest masses of atomic particles and the quantized charge of those particles. Therefore, a given chemical element may only emit radiation of specific wavelengths. Because this excitation and emission is a well-understood and documented 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. We have found that reasonable laboratory conditions produce emission spectra exactly as stated in the descriptions here.