Degenerate Modes in Photonic Crystal Cavities: Examining Resonant Frequencies

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In summary, the conversation discusses the possibility of two degenerate modes, quadruple0 and quadruple90, existing at different resonant frequencies in a 2x2 photonic crystal ring resonator. The speaker is reviewing a paper that shows modal profiles for these modes and is using a commercial EM solver to simulate the photonic crystal. They question why these modes occur at different wavelengths and why modes degenerate in the first place.
  • #1
shpongle
Can two degenerate modes have different resonant frequencies? I am asking question in context of resonance in photonic crystal cavities.

I am reviewing a paper (I have attached it).

Figure 2 (a) and (b) of this paper show modal profile for 2x2PCRR (photonic crystal ring resonator). In this figure two degenerate modes - quadruple0 and quadruple90 exist at different resonant frequencies!

This is possible? I thought degenerate modes have same energy and resonant frequency values.
 

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  • #2
I'm sorry you are not generating any responses at the moment. Is there any additional information you can share with us? Any new findings?
 
  • #3
I read "On the other hand, a pair of doubly degenerate modes at" to mean that each of the wavelengths exhibits a double degeneracy, and that there are a pair of wavelengths.

I agree that degeneracy refers to multiple modes with the same energy; the phrasing of the article is confusing.
 
  • #4
Many thanks for taking interest in reading the paper.

I am using using CST Microwave Studio, a commercial EM solver to simulate a simple photonic crystal given in figure 2(b) of this paper. The top crystal with a smaller cavity.

My question is:

Why do Quad0 and Quad90 occur at different wavelengths ? Quad90 is a degenerate mode of Quad0, shouldn't they occur at same wavelengths?

Also, out of curiosity, why do modes degenerate?
 
  • #5


I can confirm that it is possible for two degenerate modes to have different resonant frequencies in photonic crystal cavities. In fact, this phenomenon is commonly observed in photonic crystal structures due to the complex and unique behavior of light in these systems.

Degenerate modes refer to modes that have the same energy and frequency, but they can still have different spatial profiles. In the case of photonic crystal cavities, the unique structure and geometry of the cavity can result in different resonant frequencies for degenerate modes.

In Figure 2 (a) and (b) of the paper you have attached, we can see that the two degenerate modes, quadruple0 and quadruple90, have different spatial profiles and therefore, different resonant frequencies. This is due to the fact that the photonic crystal ring resonator has an asymmetrical structure, which can lead to mode splitting and different resonant frequencies for degenerate modes.

It is important to note that this phenomenon is not limited to photonic crystal cavities and can also occur in other types of resonators, such as microcavities and waveguides. Therefore, it is crucial to carefully analyze and understand the unique properties of each photonic crystal structure in order to accurately predict and control the behavior of degenerate modes.

In conclusion, it is possible for two degenerate modes to have different resonant frequencies in photonic crystal cavities. This is a result of the complex behavior of light in these structures and can be observed in various types of resonators. Further research and analysis are needed to fully understand and utilize this phenomenon in photonic applications.
 

Related to Degenerate Modes in Photonic Crystal Cavities: Examining Resonant Frequencies

1. What are degenerate modes in photonic crystal cavities?

Degenerate modes in photonic crystal cavities are multiple modes that have the same resonant frequency. In other words, they have the same energy level, making them indistinguishable from each other. This phenomenon occurs due to the symmetry of the cavity structure.

2. How are resonant frequencies in photonic crystal cavities examined?

Resonant frequencies in photonic crystal cavities can be examined through various techniques such as optical spectroscopy, transmission measurements, and scanning electron microscopy. These techniques allow researchers to observe the resonant frequencies and degenerate modes of the cavity.

3. What is the significance of examining degenerate modes in photonic crystal cavities?

Studying degenerate modes in photonic crystal cavities is important for understanding the behavior and properties of these structures. It can also help in the design and optimization of photonic devices such as lasers, sensors, and filters.

4. How do degenerate modes affect the performance of photonic crystal cavities?

Degenerate modes can affect the performance of photonic crystal cavities by causing unwanted mode coupling, leading to decreased efficiency and signal quality. However, they can also be beneficial in some cases, such as enhancing the sensitivity of sensors.

5. Can degenerate modes be controlled in photonic crystal cavities?

Yes, degenerate modes can be controlled in photonic crystal cavities through various methods such as changing the cavity geometry, introducing defects, or using different materials. This allows for the manipulation of resonant frequencies and can be used to enhance the performance of photonic devices.

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