Question about power broadening

A
Thread starter kelly0303
Start date Jun 23, 2023

In summary, the conversation discusses the effects of atomic ensemble and laser linewidths on the interaction between the two. It is mentioned that using a laser with a fixed linewidth of 1 MHz on an atomic ensemble with a Doppler broadened linewidth of 10 MHz will result in a peak of 1 MHz linewidth, with only 10% of the atoms interacting with the laser. However, increasing the power of the laser will cause power broadening and increase the effective linewidth to 10 MHz, resulting in the laser interacting with all the atoms in the cell.

Jun 23, 2023

kelly0303

Hello! If I have an atomic ensemble (say in a cell) with a Doppler broadened linewidth of 10 MHz and I have a laser of fixed linewidth of 1 MHz. If I keep the laser frequency fixed on the center of the atomic transition (say that I measure the laser transmission), I would see a peak of 1 MHz linewidth, but only 10% of the atoms will interact with the laser (I assume that anything beyond 1 linewidth doesn't interact just to simplify the question). If I increase the power of the laser a lot, I will have power broadening. If that makes the effective linewidth 10 MHz, does it mean that now I would see a transmitted line of 10 MHz linewidth and the laser will interact with all the atoms in the cell? Thank you!

1. What is power broadening?

Power broadening is a phenomenon that occurs when the spectral lines of an atom or molecule become broader due to an increase in the power of the incident radiation. This can be caused by factors such as increased temperature or pressure, or by the use of high-powered lasers.

2. How does power broadening affect spectral lines?

Power broadening causes spectral lines to become broader and less distinct. This is because the increased power of the radiation causes more energy levels within the atom or molecule to be excited, resulting in a wider range of emitted wavelengths.

3. What is the difference between power broadening and Doppler broadening?

Power broadening is caused by an increase in the power of the incident radiation, while Doppler broadening is caused by the thermal motion of atoms or molecules. Power broadening results in broader spectral lines, while Doppler broadening causes a shift in the position of the lines.

4. How does power broadening affect the accuracy of spectroscopic measurements?

Power broadening can make it more difficult to accurately measure the positions and intensities of spectral lines. This is because the broader lines can overlap with each other, making it harder to distinguish individual lines and accurately determine their parameters.

5. Can power broadening be used to study the properties of atoms or molecules?

Yes, power broadening can be used as a tool to study the energy levels and properties of atoms and molecules. By analyzing the broadening of spectral lines under different conditions, scientists can gain insights into the structure and behavior of these particles.