Heating by Laser: DC Temperature & Modulation Frequency

This phenomenon is observed in carbon black materials, where the static temperature increases with laser modulation frequency.In summary, the static temperature at steady state when a modulated laser beam is incident on a black absorber is found to increase with the frequency of modulation. This is because at higher frequencies, the material has less time to absorb and dissipate the energy from the laser, resulting in a lower rate of energy absorption and dissipation and ultimately a higher static temperature. This phenomenon is observed in carbon black materials.
  • #1
bushjun
1
0
A laser beam whose intensity is modulated (at frequency, f) is falling on a black absorber. For the surface temperature, there will be two components: (1) modulated temperature or photothermal wave and (2) a static dc temperature component.

The photothermal signal properties are well known. But, can some one clarify why the static temperature at steady state is a function of laser modulation frequency ?
To make it clear, at steady state, the static temperature is found to be increasing with frequency of laser modulation. The material is carbon black.

For the laser, energy is independent of modulation frequency. Why the dc temperature
goes up with frequency ?
 
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  • #2
The answer is related to how quickly the material can absorb and dissipate the energy from the laser. Generally speaking, when the laser is modulated at a higher frequency, the material has less time to absorb and dissipate the energy, resulting in a higher static temperature. This is because the time available for the material to absorb and dissipate the energy is reduced as the frequency increases. The rate of energy absorption and dissipation will therefore be lower, leading to a higher static temperature.
 

FAQ: Heating by Laser: DC Temperature & Modulation Frequency

1. How does heating by laser work?

Laser heating involves focusing a high-powered laser beam onto a specific material or surface, causing it to rapidly absorb the laser's energy and increase in temperature. This is because the laser's light is converted into heat energy when it interacts with the material's molecules.

2. What is DC temperature in relation to heating by laser?

DC temperature refers to the steady-state temperature that a material reaches when continuously heated by a laser. This is in contrast to AC temperature, which fluctuates due to modulation of the laser's power or frequency.

3. How does modulation frequency affect laser heating?

Modulation frequency refers to the rate at which the laser's power or frequency is changed. This can affect the heating process by either increasing or decreasing the temperature of the material. Higher modulation frequencies can lead to faster heating, while lower frequencies may result in a slower increase in temperature.

4. What factors can impact the efficiency of laser heating?

The efficiency of laser heating can be influenced by several factors, including the type of material being heated, the intensity and duration of the laser beam, and the surface properties of the material. Other factors such as ambient temperature and the presence of impurities can also affect the efficiency of laser heating.

5. What are some applications of heating by laser?

Laser heating has a wide range of applications in various fields, including materials science, biochemistry, and industrial processes. It can be used for precision welding, cutting, and drilling of materials, as well as for heating and melting of materials in microelectronics and medical procedures like laser surgery. Laser heating can also be utilized in research for studying material properties and chemical reactions at high temperatures.

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