Theoretical and experimental investigations of loss behavior in the infrared in quartz hollow waveguides with rough inner surfaces

Transmission losses in quartz hollow waveguides with rough inner surfaces have been measured, and an anomalous loss decrease has been observed just beyond the resonance wavelength at the infrared. Detailed analyses have been conducted to check the applicability of available theories in the prediction of additional loss increases or decreases in wide infrared-wavelength regions. A new theory based on a thin-film-coating model has also been presented for the first time, to our knowledge, to describe the additional loss behavior.