Exploring Anomalous Dispersion for Resonant Cavities

In summary: No i can't. I'm not working in sciences/engineering, I just have an interest in solar cells and some knowledge from a university education in electronics engineering. I posted on the forum because I was stuck on the unknowns I outlined earlier and I wasn't sure where to turn to next. I just like to search for the sake of learning.
  • #1
material
14
0
In anomalously dispersive media, the change in phase velocity with wavelength is negative; that is dv/dλ < 0.

I wanted to ask:

(a) whether you could fit a wide range of frequencies into a resonant cavity by taking advantage of anomalous dispersion
(b) whether a material like this exists for the 300nm < λ < 1100nm range and
(c) whether it exhibits the behaviour of n = λο/λd,

where n = index of refraction, λο = wavelength between 300 and 1100nm, and λd = desired wavelength to design the resonant cavity with λd = 300nm.

(d) whether you could design the resonant cavity so that light goes in but doesn't escape easily because of the waveguide modes and because of total internal reflection characteristics.

I am thinking if you could etch tiny rectangular cavities filled with the right medium on the surface of a silicon solar cell and focus the surrounding light into the cavity, then more of the light will be absorbed by the silicon.

What my maths thinking is:
fo=c/λο, c=300Mm/s
v=fo*λd, v = phase velocity
if λd=300nm,
@ λο=300nm, fo=c/λο=1PHz, v=fo*λd=300Mm/s => n=c/v=1
@ λο=1100nm, fo=c/λο=0.272PHz, v=fo*λd=81.82Mm/s =>n=c/v=3.667
 
Science news on Phys.org
  • #2


material said:
I am thinking if you could etch tiny rectangular cavities filled with the right medium on the surface of a silicon solar cell and focus the surrounding light into the cavity, then more of the light will be absorbed by the silicon.

Interesting application - have you been able to estimate what the theoretical improvement in energy efficiency would be in such a solar cell device?

There are parabolic reflectors for example that do a similar thing - they focus the sun rays whilst tracking the sun as it moves in the sky. I believe that energy enhancements of the order of about 300% are possible in these systems.

The solar cell itself is a very specialised high durability cell that requires a cooling system. (NASA developed one type of these solar cells for some of their satellites and probes)
 
  • #3


Interesting application - have you been able to estimate what the theoretical improvement in energy efficiency would be in such a solar cell device?

I'm not sure how much of a difference it would make. There's a lot of issues that I can imagine would affect the outcome. If the cavity is a cube, then the sides of the cube would be 300nm/1.414... = 212nm long for a wavelength at 300nm. I'd need to consider the distance between each cavity so that the walls between each cavity are not so thin that the light goes through the cavity walls. The critical angle of the boundary between the cavity and the next layer of the solar cell must be less than 45 degrees for all frequencies. A micro/nanoscopic lens would have to have the right properties to direct the light within the cavity. I think there would be heating issues. Of course this all depends on whether I understand light dispersion correctly and whether the technology is there at the right price.

I just put the idea out there. I was hoping someone with more knowledge can validate or invalidate the idea.
 
  • #4


material said:
I'm not sure how much of a difference it would make. There's a lot of issues that I can imagine would affect the outcome. If the cavity is a cube, then the sides of the cube would be 300nm/1.414... = 212nm long for a wavelength at 300nm. I'd need to consider the distance between each cavity so that the walls between each cavity are not so thin that the light goes through the cavity walls. The critical angle of the boundary between the cavity and the next layer of the solar cell must be less than 45 degrees for all frequencies. A micro/nanoscopic lens would have to have the right properties to direct the light within the cavity. I think there would be heating issues. Of course this all depends on whether I understand light dispersion correctly and whether the technology is there at the right price.

I just put the idea out there. I was hoping someone with more knowledge can validate or invalidate the idea.

Can you experimentally validate the application?

(should protect any potentially novel ideas via either secrecy or patent before you publicise them)
 
  • #5


Driftwood1 said:
Can you experimentally validate the application?

No i can't. I'm not working in sciences/engineering, I just have an interest in solar cells and some knowledge from a university education in electronics engineering. I posted on the forum because I was stuck on the unknowns I outlined earlier and I wasn't sure where to turn to next. I just like to search for the sake of learning.
 

What is anomalous dispersion and how does it relate to resonant cavities?

Anomalous dispersion is a phenomenon in which the phase velocity of light is greater than the group velocity, causing the light to spread out over time. This can occur in resonant cavities, such as optical or microwave cavities, where the light is confined and reflected many times, leading to interference effects that result in the anomalous dispersion.

What are some applications of exploring anomalous dispersion in resonant cavities?

Exploring anomalous dispersion in resonant cavities has many practical applications, such as in optical communications, where it can be used to control the dispersion of light pulses and improve signal transmission. It is also important in the design of high-precision optical instruments and devices, such as laser gyroscopes and frequency combs.

What techniques are commonly used to study anomalous dispersion in resonant cavities?

One of the most commonly used techniques is the cavity ring-down spectroscopy, which measures the decay of light intensity in a resonant cavity as a function of time. Other techniques include using Fabry-Perot interferometers, Fourier-transform spectroscopy, and spectroscopy with tunable lasers.

What are some challenges in exploring anomalous dispersion in resonant cavities?

One of the main challenges is the precise control and measurement of the dispersion properties in the cavity, as well as understanding the complex interference effects that can occur. Additionally, the materials used in the cavity must have low loss and high reflectivity to achieve the desired level of confinement.

How can exploring anomalous dispersion in resonant cavities contribute to our understanding of fundamental physics?

Studying anomalous dispersion in resonant cavities can provide insights into fundamental physical phenomena, such as quantum mechanics and the behavior of light in confined spaces. It can also help in developing new theories and models for understanding and predicting the behavior of light in various systems.

Similar threads

  • Advanced Physics Homework Help
Replies
6
Views
1K
Replies
16
Views
1K
Replies
46
Views
2K
  • Introductory Physics Homework Help
Replies
2
Views
4K
  • Quantum Physics
Replies
6
Views
6K
Replies
2
Views
2K
  • Beyond the Standard Models
2
Replies
39
Views
4K
  • Engineering and Comp Sci Homework Help
Replies
2
Views
16K
  • Engineering and Comp Sci Homework Help
Replies
3
Views
1K
Back
Top