Optical absorption in glass: investigation using an acoustic technique.

Area of Science:

• Acoustic physics
• Optics
• Materials science

Background:

• Experimental studies show chopped light can produce sound in gases.
• This sound generation occurs even when the gas itself does not absorb infrared light.
• The source of the sound was investigated to understand the underlying mechanism.

Purpose of the Study:

• To identify the source of sound produced by chopped light in a high-pressure gas cell.
• To elucidate the mechanism responsible for sound generation.
• To correlate experimental findings with theoretical models.

Main Methods:

• Experimental setup involving a high-pressure gas cell and chopped light.
• Measurement of sound pressure amplitude as a function of gas pressure.
• Theoretical modeling to explain observed phenomena.

Main Results:

• Sound generation is attributed to the interaction of incident light with the cell window.
• Sound pressure amplitude exhibits a p0(1/2) dependence on cell pressure (p0).
• A diffusion process is implied as the responsible mechanism.

Conclusions:

• The existence of an optically absorbing surface layer on the cell window is crucial for explaining the data.
• Theoretical application successfully accounts for both quantitative and qualitative aspects of the experimental results.
• Findings are consistent with studies on laser-induced damage in glasses.