Modelling

Physics 101 - Light

Electromagnetic radiation is energy travelling as waves or photons. This is not the place or the time to go into this discussion [1] but Einstein and Infeld said it well:

"But what is light really? Is it a wave or a shower of photons? There seems no likelihood for forming a consistent description of the phenomena of light by a choice of only one of the two languages. It seems as though we must use sometimes the one theory and sometimes the other, while at times we may use either. We are faced with a new kind of difficulty. We have two contradictory pictures of reality; separately neither of them fully explains the phenomena of light, but together they do." -- Albert Einstein and Leopold Infeld, The Evolution of Physics, pg. 262-263.

Light, or the visible light spectrum range from $ \in [400 - 700] $ nm in the electromagnetic radiation spectrum. XX insert picture of Elmag spectrum here XX. Above, with higher wavelengths, you will find infrared radiation (also known as IR), and under you will find the ultraviolet radiation (also known as UV). We call it visible light due to the fact that our eyes can only "pick up" these wavelengths. For this project we will mostly focus on light $ \lambda \in [470,520] $ nm region.

You have probably heard that nothing can travel faster than light? But not that many (non-physicist) remembers what velocity light actually travels with. In most cases it's enough to say that light travels in $ \sim 3.0 \cdot 10^{8}$ km/h in vacuum or $ \sim 6.7 {\cdot 10^{8}} $mph.

When talking about light there is a couple of expressions that is good to know the meaning of

Insert some words here

Physics 101 - LED

Not monochromatic, circuite explanation

Physics 101 - Wavelength

The given wavelength $\lambda$ for a lightsource can be found by XX INSERT FORMULA HERE XX, by knowing the grid spacing, $d$ and angle, $\theta$.

Physics 101 - (Bio)laser

What is a laser?

A laser is a device that emits monochromatic light amplificated by stimulated emission of electromagnetic radiation, hence the name (“Light Amplification by Stimulated Emission of Radiation”).

The first laser was built in 1960 by Theodore H. Maiman, based on theoretical work by Charles Hard Townes and Arthur Leonard Schawlow. What makes a laser different from other light sources is the fact that it emits its light coherently. This means that the stream of light will stay narrow over a long distance and can also be focused in a tight spot, like for example for laser cutting or a laser pointer.

A laser consists mainly of five parts: the gain medium, the laser pumping energy, the high reflector, an output coupler and a laser beam. The gain medium is a material which allows light to amplify. This is usually located in an optical cavity. What this means is that there is a mirror on either side of the medium, in order to make the light bounce back and forth. This amplifies the light, as it passes through the gain medium each time. One of the mirrors is usually not 100% reflective, since there will a small output (the laser beam). For anything to happen within the optical cavity we need a power source that allows the gain medium to amplify the light. This energy is supplied through a process called pumping and is usually either light or an electrical current.

The biolaser

When we use the term biolaser we refer to a biological component that posesses the same qualities as a laser. What we mean by this, is that the gain medium is now the biological component. Snakke om GFP.

[1] if you want to read more about the waves vs. photons disussion: