Can a 10 nm facet area achieve 10^12W/m^2 for laser heating on a tungsten tip?

In summary, the person is doing some basic heat calculations about a CW laser illuminated tungsten tip and found that after solving the 1d heat equation for a cone and then including a rod on the other end (held at T=300K), they can apply 10^12W/m^2 onto the tip. However, they are worried about the penetration depth of the photons into the tip and what that means to the tip on such a small scale.
  • #1
Benindelft
12
0
I am doing some basic heat calculations about a CW laser illuminated tungsten tip (which should be used for photoemission) - I started to play with the tip geometry to try and find a way to get more flux Watts/metre^2 onto the tip without it melting. I found that after solving the 1d heat equation for a cone and then including a rod on the other end (held at T=300K):

{dT=\frac{Q}{k*A(z)}dZ=\Dint{T_{facet}}{T_{shaft}}=\Dint{Z_{facet}}{Z_{shaft}} \frac{Q}{kz^{2}tan^{2}\theta\pi}dZ}
which comes out as

{Q=\frac{T_{facet}-300}{\frac{facetradius^{-1}-shaftradius{^-1}}{tan^{\theta\pi}k}+\frac{shaftlength}{shaftradius^2{\pi}k}}}

This assumes (wrongly of course) that all the laser power is absorbed on only the facet of the tip.

Now my calculations tell me that if I make the facet area around 10 nm i can apply 10^12W/m^2.

Is this possible? Am I not doing something that should ablate my tip immediatly ?
 
Science news on Phys.org
  • #2
I might be completely on the wrong track, but - would it not cause problems if the object you want to heat is so much smaller than the wavelength of the light you are using ?

If it is visible light, we are talking of ca. 500nm, and let's say 1000nm if you use near infrared. So your object at 10nm is about 100 times smaller, have you considered this in your calculations ?
 
  • #3
I don't have anything in the calculations, but I am pretty sure that we get quite a strong local electric field enhancement, that's all good (as long as it doesn't blow up the tip). There might also be some plasmon enhancement I think (but really not sure , I read that tungsten doesn't have a strong plasmon enhancement).

If there is an increase in the Power Density then that's not important (I can just supply less power initially to compensate). I am more worried about the penetration depth of the photons into the tip and what that means to the tip on such a small scale?

Can you suggest anything other things to consider?
 

1. What is nanoscale laser heating?

Nanoscale laser heating is a process in which a laser is used to heat materials at the nanoscale level, meaning on a scale of one billionth of a meter. This can be used for various purposes such as manipulating the properties of materials, studying their behavior, and creating new materials with unique properties.

2. How does nanoscale laser heating work?

Nanoscale laser heating works by using a focused laser beam to target a specific area on a material. The laser beam is absorbed by the material, causing its temperature to rise. The intensity and duration of the laser beam can be controlled to achieve precise temperature changes in the material.

3. What are the applications of nanoscale laser heating?

Nanoscale laser heating has various applications in fields such as materials science, biology, and medicine. It can be used to study the thermal properties of materials, manipulate their shape and structure, and even trigger chemical reactions at the nanoscale level. In medicine, it can be used for targeted drug delivery and precision surgery.

4. Are there any challenges associated with nanoscale laser heating?

Yes, there are a few challenges associated with nanoscale laser heating. One of the main challenges is controlling the heat distribution in the material, as it can be difficult to confine the heat to the desired area. Additionally, the high temperatures produced by the laser can also cause damage to the material if not carefully controlled.

5. What advancements are being made in nanoscale laser heating?

There are ongoing research and development in the field of nanoscale laser heating to overcome its challenges and expand its applications. Some advancements include the use of plasmonic nanoparticles to enhance the heating effect, developing techniques for precise control of heat distribution, and using multiple laser beams for more complex heating patterns.

Hot Threads

Recent Insights

Back
Top