Addiction, obsession, love, vocation?

I was looking in bewilderment at some friends who are absolute workaholics and it made me think of my own commitment to research: is it an addiction that needs curing/an obsession that needs controlling/love that needs careful nurturing/a calling and vocation to be grateful for?

If you have the patience to go through my muddled thoughts, then tell me if your own experiences are similar.

When people ask if I enjoy my work I am usually at a loss. How to explain the conundrum that I find scientific research to be?

So the good days are when you have a brilliant idea and are able to translate it into a design/experiment, something tangible that works. The joy of getting results that make sense and answering the question you posed: “what if we….” or “can it…”. On such days the only place I want to be is my lab. Nothing else matters. Really! I don’t want to go out, shop, watch films, meet friends. I just want to be able to keep playing with that lovely joyous problem. The high it gives me is beyond anything (yes not even chocolate, or the backhand of Justine Henin!) I think about the problem all the time, I see it everywhere, in my dreams and when I am awake. I am consumed by it. So I don’t know if this is just obsessive behaviour, or behaviour typical of an addict or in a more positive way, love for something.

The bad days are when the ideas dry up, when the solutions aren’t forthcoming and every attempt ends in failure. It is torture then to go to lab and I have to drag myself from the pits of frustration by sheer will.

All in all I find research is probably 65 days of pure high and 300 days of varying degrees of frustration. What does it say about me that the 65 days keeps me hooked?

What is your experience of your work?

By artiagrawal Posted in General

Very excited to see this tweet from the American Physical Society

RT @apsdiversity: Homer Neal, 1st African American physicist elected as APS Vice President!

— APS Physics Wash Ofc (@APSPhysicsDC) July 9, 2013


You can read more about Homer Neal’s fantastic career here.

It is inspiring for everyone, especially young scientists and students to see ethnic minority scientists (and women!) as leaders in important institutions.

Steady on! Wide angle BPM is here

What a topsy turvy 2 weeks!

Imagine a Wimbledon where Roger Federer and Serena Williams are ousted like that! And then the first Ashes tests with all its twists and turns….In all this tumult, I need a steadying anchor.
Where else to turn but Science and writing?

I am going to look at some of my own past research in a bid to calm my mind (England have just lost the 5th wicket in their second innings).

Wide angle beam propagation methods (BPM) were the core focus of my PhD thesis (that seems so long ago now!). It may sound like a mouthful and/or gobbledygook but the wide angle BPM is really important for photonics modelling and the logic is straight forward.

The beginning of BPM methods was with algorithms that made the paraxial or Fresnel approximation. This amounted to saying that the light waves would make a small angle with respect to the propagation axis, or in other words light would be almost parallel to the propagation axis (we will take that as the z axis in this post). But with complicated structures that have branches (y-junctions, sharp 90o bends), or high index contrast, this assumption leads to significant error when simulating light propagation.

The light waves (for example in a y-junction) do not travel at small angles to the z axis, so obviously carrying on with the assumption was not practical. In other cases where the refractive index change is large (relative to the propagation variable), backward propagating waves or waves at large angles get generated and again the paraxial approach is not sufficient.
Hence the need for wide angle formulations was felt.

You may ask: why didn’t people incorporate wide angle assumption from the start?

The answer to some extent is due to the mathematical difficulty. If you look at the wave equation it contains second order derivatives with respect to x,y and z.
The x and y derivatives are the transverse derivatives and go to the right hand side of the equation (along with the refractive index variation), while the change with respect to z, stays on the left. Effectively we are trying to see the evolution of the field at different z values. Solving this second order differential equation in z is quite a challenging task. The Fresnel or paraxial approximation allows us to convert it to a first order differential equation in z, thus hugely simplifying things.

Going to wide angle formulations implies, reinstating the second order derivative or finding clever ways to deal with it. There has been a huge body of work on this especially in the 90’s and the last decade. As a result we have wide angle BPM formulations in most popular numerical methods: Finite Difference, Finite element etc. Many of the popular commercial software now incorporate wide angle calculations or offer the option.

So have a look at some of the theory in this paper and download preprint-oqe-06 fdssnp paper and pre-print-ptl06 paper. Tell me what you think!