Spiralling at a rapid rate

As promised I will try and write a little bit about research too!

So here goes.

At OWTNM 2014 in Nice I met a researcher from Aston University in Birmingham. They use fs laser inscription to write waveguides in Lithium Niobate (the spot exposed by the laser has a lower index than Lithium Niobate. Therefore by writing several spots around a central “core” area, it is possible to create low index “holes” around a core, and guide light in this core by total internal reflection).

We got talking and now we are trying to collaborate. The idea is that I use my experience with the spiral design to optimize a spiral waveguide that offers sufficient guidance with low loss and changes the dispersion. While Mykhalo will make the waveguide and test it.

The challenge here is that the index contrast created is very small: ~-.015 to -.02. With such a low index contrast changing the total dispersion (by making the waveguide dispersion large) is quite tough. Since the index contrast is low, the field is not easily confined to a small spot and the effective index of the guided mode remains very close to the material refractive index.

So I have to find a way to alter the dispersion appreciably. Secondly Mykhalo wants the results before end of September! So its quick time work.

And I am loving it.

It is really exciting to work on something real-life and challenging. Even more so because there is the possibility of seeing my own design being fabricated!

By artiagrawal Posted in General

How did we get here?

Have you wondered how you reached the particular point you are at (in a project/relationship/job/career..)?

I just realised that I had started this blog with the intention of writing primarily about my research interests and current work. I realise now that for the most part I write about loads of other stuff. The blog has become a means to voice my opinions on Science policy, education, Science related media and so much more….
Little did I know that having a platform to voice one’s views is dangerous: it can draw a person in and captivate them.

So I shall try and be good and balance the writing a bit and write a little bit more on research as was the original plan. Though I can’t quite give up writing about the other stuff…

The question is how does one end up here, having drifted (in this case in a pleasant way) from the original purpose?

By artiagrawal Posted in General

Working away

As some of my posts indicate there are times when I feel as buried under work as anyone. And I am sure you can attest to feeling the same:
– not enough hours to finish the work waiting
– thinking about work while you should be engrossed in family, friends
– feeling stressed and perhaps even low confidence because it seems you cant cope

These things are increasingly happening to academics. In the UK, the employment contracts many of us sign do not stipulate maximum working hours or exact duties. Instead we are meant to perform the taks considered necessary/relevant to our role by our employer. the time we spend performing these tasks is also in some ways implicitly decided by our employer.

Where does this leave us if we are over burdened?

The situation seems the same in every university: (junior staff especially) academic staff toiling away to teach several courses, while trying to establish themselves as research supestars. Then there is the admin work…In order to cut costs, staff are fired and the work redistributed amongst fewer staff members, who somehow are supposed to do more with less (less time, less rest, less resources).
Apply for grants, publish in top journals, get excellent teaching scores from students, publish a book, do the admin… the list is endless.

In trying to achieve these targets we put in ever increasing hours. Holidays are of shorter duration every year and some how the work laptop finds a way ito come on even during weekends, late nights and holidays.

There is no overtime money from the employer for any of this. No one from the Higher Education authority or any emplyment body/union to hold these employers to account.

Now this may seem like a rant and a moan (it is). But it also more.

It is upto us to not fall into this trap. While we may not all be able to walk up with our resignation lettter and walk into a better job, we can assert some control over our minds.

Our anxiety at not being able to do as much as we think is needed, is perhaps our biggest problem. If we can step back from the situation and the anxiety to objectively view things, we can make better decisions about our goals and how to achieve them.

I read an article recently which I found quite useful: http://www.timeshighereducation.co.uk/features/feature-work-less-do-more-live-better/2014929.article

In my view we need and deserve to be treated more fairly by employers, a complete change in attitude is needed in educations. While we work towards this, we can also make changes in our individual lifestyles, thinking and perhaps self-management to help ourselves.

Teamwork and jigsaws

I was looking at the work of Daniel Stokols, an environmental psychologist, to see if I could find any work on how buildings and their design impacts reactions of students.

What I did find was the Jigsaw Classroom, a cooperative learning technique. The technique was developed to help teach in racially diverse classrooms and avoid situations like the Columbine massacre developing.

The idea is to get students to work in teams in such an effective manner, with each student acting as the proverbial vital piece of the jigsaw, that completes the puzzle. In this technique all members of the team learn to respect the importance and contribution of every other team members, learn to work with them, overcoming distrust and fear. Each person reliases that no one can be a freeloader or minimise the work of others.

It should be possible to adapt this method to tackle any kind of divisiveness based on difference of gender, sexual orientation, race, religion, age and even disability.

I find it amazing that there are such innovative techniques to help delvier better teaching!

In a bind

Student days… my glasses are misting in memory of those fun filled days: laughter, friends, evenings out, and such like.

Unremarkably, this kind of memory is a selective. In these sepia printed snapshots of my youth, there is no sign of the tensions associated with exams, report submissions and incomplete projects!

Well, as it is, I dont have to rely on memory for that!

I am attending the MA in Academic Practice here at City Uni London and along with the fabulous learning (on how to teach) come the assignments, group work, assessments and the like. So if this post is a little rambling forgive me for my brains are scrambled! Right now I am well behind on two chunks of my module on Technology Enhanced Academic Practice (TEAP):

- social bookmarking: we need to use a tool like DIIGO to bookmark sites and write about some of these
– the final project (also the biggest chunk of the module!)

This module has been all about using technology in a blended learning environment: mixing traditional teaching methods and approaches with technology. All of it felt new (even the traditional teaching and learning models, leave alone the new stuff).
I learned about things like:
•Salmon’s five step model
•Community of Practice/Community of Inquiry
•Reflective practice
•Constructive alignment
•Social constructivism
•Behaviourism
•Problem-based learning
•Connectivism
•Situated Learning
•Humanism
•Laurillard’s Conversational Framework
•Cognitivism

So the tech stuff (which is increasingly important given the digital nature of our lives) in the course was on:
– how to use online communities in teaching and learning. It is possible to use wikis and blogs etc. to get students to interact with one another as well as the instructor to learn, sometimes remotely and even asynchronously
– reflection: getting students to reflect on their work and learning to improve their learning outcomes
– tools like Diigo for social bookmarking, blogs for interaction

My project is on formative assessment using tools like Moodle (online platform used my many universities for education). The formative assessment idea is that students learn as they test themselves, but they learn better if they can get feedback very quickly (even real time) and they are able to judge where they are weak, or what mistakes they tend to make.
So I (over reached) and said that I would make a series of short numerical Physics questions, which can be delviered via Moodle and be set up in such a way that students can get feedback as they attempt the question.

Not only that! I then thought this was too easy. So I would then make a series of short videos explaining how people could use Moodle to set up such tests, since many colleagues find it difficult to do this. What was I thinking?!!!!

And now here I am, using this blog and online community to moan about the hardships of my student life. I have enjoyed the course tremendously and it has sparked so many new ideas in my head about teaching. But it has also reminded me how my students feel.

So if anyone of you is in danger of forgetting the pressures of student life, enroll into a course now!

Parity-time symmetry at OWTNM

One of the most interesting talks at the conference was on Parity-Time symmetry by H.Benisty and relating these to reciprocity or lack thereof.

Hermitian operators have real eignvalues. By adding imaginary terms of opposite signs to the diagonal terms, the eignevalues can still remain real! These imaginary terms in the physical picture can be seen as loss/gain. The possibility of spatial-nonreciprocity comes in.

Here are a list of papers worth looking at to get more on this:
1. Physical Review Letters, Vol. 80, pp. 5243-5246, 1998
2. Nature Physics, Vol. 6, 192-195, 2010
3. Optics Express, Vol. 13, pp. 3068-3078, 2005
4. Physical Review Letters, Vol. 106, 213901, 2011
5. Nature Materials, Vol.12, 108-113, 2012
6. Optics Express, Vol. 19, pp. 18004-18019, 2011
7. Optics Express, Vol. 21, pp. 21651-21668, 2013

Unusual two days at ECIO

Yesterday and today have been a bit unusual for me in attending ECIO. I have hardly listened to any talks these two days!

No, I haven’t been lounging by the beach….

My time has gone in some long discussions with the good folk at Photon Design, a company that makes numerical simulation software. We spent a long time discussing the modelling of band gap fibres, and how quasi-crystals could be modelled, as well as putting their new FETD software through its paces.

This new FETD that Photon Design are offering, allows for higher order elements (shape functions) to be used, and is applicable for both 2D and 3D problems. the claim is that though it takes slightly longer than FDTD (which is first order accurate) if you want higher accuracy, with this program, it is possible to increase the order and get higher accuracy. The mesh is conformal and irregular so it can be concentrated in regions where the field changes more rapidly, and a combination of these two factors make it better than FDTD (a bit faster, and more accurate) for more demanding problems. I would like to of course try the software out to verify the claim and see how it performs for my problems of interest.

But this underscores some of the things I tried to get across at CLEO in my short course:
– test drive commercial software before buying
– benchmark their performance for problems with known solutions of increasing complexity (finally comparing where only experimental results are available)
– look at the documentation on offer: is it comprehensive, easy to understand and does it also agree with literature

LEts see what tomorrow brings!

The first day at ECIO

So I am here in lovely, sunny Nice on the Azur coast of France, to attend the European Conference on Integrated Optics (ECIO) and the Optical Waveguide Theory and Numerical Modeling Workshop (OWTNM).

As you can expect the conferences weren’t the only draw: Nice is lovely.It combines the charm of a pretty seaside town with great food and fabulous weather. Yesterday I had lunch at the seaside overlooking the blue, blue waves, while people kayaked, sunbathed, parasailed, speedboater and swam…

Onwards to the conference today, the first day. I always like coming to ECIO/OWTNM as these are slightly smaller and more intimate with 1 maybe 2 sessions in parallel, giving a lot of opportunity to interact. It feels less hectic and yet is still rewarding work wise.

The talk that I found quite enjoyable today was a plenary by G Roelkens (Ghent University/IMEC) on Silicon Photonics beyond the datacomm and telecoms applications. He described some of the work at Ghent and IMEC on using Si photonics for sensing. There was a very large number of experiments described: on sensing of biological species using Si ring resonators, trace gas detection, Laser Doppler Vibrometry to detect changes in object position, blood flow velocity, and many others.

One thing that he mentioned and I want to look up is this: out coupling of light from Si devices such as these can be difficult. Grating couplers made in these Si wave-guides, can suffer from Fresnel reflection (due to large index contrast between Si and the medium to which light is being coupled) and second order Bragg reflection. Apparently some tiled focused grating couplers can reduce the Fresnel reflection significantly. The papers he cited are:
Optics Express, 22278, 2012
Optics Letters, 37 (21), pp 4356, 2012.

If you read these let me know what you think of them!

Photonics video

SPIE have made a brilliant short video about photonics. Here is the link: http://laserclassroom.com/day-without-photonics/

Enjoy!

What I would love to do is build on this type of video: enlarge it a bit to cover more technologies and products and also to show the insides of these products, how these are made. Get into the factories, the shop floors, show all the people involved and what it takes to get a product out to market. Perhaps even show innovative ways that some photonics technologies are being used…