Wavelength calibration methods in laser wavelength measurement.

Abstract

At present, accurate wavelength calibration plays an important role in laser spectrum measurements. Although the wavelength calibration methods have been investigated for a long time, there are no techniques that are particularly designed for laser spectral calibration to the best of our knowledge. A mathematical model for calibrating a pulse laser wavelength is first established, to the best of our knowledge. According to the analysis formula of dispersion aberration, a flat-field concave grating in the near-infrared band is designed. Then, a wavelength calibration model based on concave grating spectroscopy is proposed. Through adjusting the spectra of each pixel, we design a calibration algorithm based on the cubic spline interpolation and kernel regression methods. By compensating and interpolating spectral data, accurate wavelengths are obtained. Finally, some experiments verify the calibration performance of the proposed method. Meanwhile, the uncertainty of measurement is also analyzed.