Ice thickness measurements by Raman scattering
  A compact Raman LIDAR system with a spectrograph was used for express ice thickness measurements. The difference between the Raman spectra of ice and liquid water is employed to locate the ice-water interface while elastic scattering was used for air-ice surface detection. This approach yields an error of only 2 mm for an 80-mm-thick ice sample, indicating that it is promising express noncontact thickness measurements technique in field experiments. 
Sergey M. Pershin, Vasily N. Lednev, Vladimir K. Klinkov, Renat N.   Yulmetov, and Alexey F. Bunkin
physics.optics