Discussion Overview
The discussion revolves around the absorbance of blue light by gold foil, specifically focusing on its ability to absorb light at around 470nm and the implications of using polished gold for this purpose. Participants explore the theoretical limits of absorption, reflection, and the practical applications of gold in filtering light.
Discussion Character
- Exploratory
- Technical explanation
- Debate/contested
- Mathematical reasoning
Main Points Raised
- One participant states that polished gold foil can absorb around 62% of blue light at 470nm and questions whether it can absorb 1 watt of this light.
- Another participant asserts that the foil will overheat at some point and suggests that it cannot absorb 100 watts of light.
- A different participant raises the concern that most of the light may be reflected rather than absorbed.
- One participant references a study showing reflectance curves for gold, silver, and aluminum, suggesting that the absorption characteristics may not be as expected.
- It is noted that the thickness of the gold foil affects its absorption and transmission properties, with thin films appearing green and thicker films leading to reduced transmission.
- Another participant emphasizes that polishing the surface increases reflectance, which reduces light absorption, and mentions that the ability to absorb 1 watt depends on the power of the light source.
- One participant points out that while gold absorbs blue to green light, it reflects light in the reddish part of the spectrum, questioning the effectiveness of gold for filtering blue light while transmitting other wavelengths.
- Suggestions are made for alternative filtering options, such as color glasses and multilayered filters, which may provide better performance for specific transmission needs.
Areas of Agreement / Disagreement
Participants express differing views on the effectiveness of gold foil for absorbing blue light, with some questioning its ability to absorb significant amounts of light due to reflection and thickness considerations. There is no consensus on the practical limits of absorption or the best methods for filtering light.
Contextual Notes
The discussion highlights the dependence of light absorption on the thickness of the gold foil and the power of the incident light source. There are unresolved questions regarding the optimal use of gold for light filtering and the implications of surface polishing on absorption and reflection.