Calibrating Raman Spectrometers Using a Neon Lamp

Abstract

The convenience of using a neon lamp for the calibration of Raman spectrometers is well established. Loader presents a tabulation of wavelength (A) in air, frequency (cm−1) in vacuum, and apparent Raman shift (cm−1) in vacuum (table 3, pp. 23–24 in Ref. 1). Strommen and Nakamoto present a tabulation of wavelength (A) in air and wavenumber (cm−1) in air (table 3.4, pp. 69–70 in Ref. 2). Both tabulations are based on the measured wavelength (A) for neon in standard air reported by Burns, Adams, and Longwell and contain 87 wavelengths for neon that are appropriate for calibration of Raman spectrometers utilizing the 488.0-nm line of an argon-ion laser. Craig and Levin offer the alternative of using the plasma lines of the laser itself for calibrating Raman spectrometers that utilize an argon-ion laser by merely detuning the laser. The tabulation of Craig and Levin includes sufficient data for calibration with respect to both the 488.0-nm and the 514.5-nm lines of the argon-ion laser. However, it may not always be convenient or desirable to remove or bypass optical elements in the system that eliminate the plasma lines of the argon-ion laser in order to use these lines for calibration after detuning the laser. For the benefit of those who need to calibrate their Raman spectrometer with respect to both the 488.0-nm and the 514.5-nm lines of the argon-ion laser and prefer to use the emission lines of a neon spectral calibration lamp rather than the plasma lines of the detuned laser, we expand the tabulation of Strommen and Nakamoto to include the needed 26 additional lines from the work of Burns, Adams, and Longwell. In addition, we briefly describe a procedure for the calibration of our Raman spectrometer with respect to the 514.5-nm line of the argon-ion laser.