Repeat, repeat, repeat

Today while I was reading up articles on solar cells I came across something that touched a real chord with me:

In the September 2014 issue of Nature Photonics, Zimmermann et al. had a commentary piece titled “Erroneous efficiency reports harm organic solar cell research” on page 669.

The authors commented that mischaracterization or solar cell power conversion efficiencies and inconsistent data being published in scientific journals (in the field of solar cells) was particularly harmful for the area. The race for getting the best results and publishing them in the journals with highest impact factor, has in part led to people being less careful about incorrect measurements and poor reporting.

The danger when such articles multiply and proliferate is that the data being reported is unreliable and one doesn’t know which data/papers to trust. The progress of the field as a whole is hampered.

Having data and results that can be trusted, repeated and verified is a must for scientific research. In some cases, the methods to be used for characterization are clearly laid out and researchers can follow these, and/or conduct standardized tests/measurements to show the veracity of their results. This instills confidence in readers about the work and should positively impact the citation of the work too.

Obviously such issues are not confined to one field alone. For numerical modeling as I have said in previous posts, benchmarking results of a new technique against existing test cases/analytical solutions is a must!

The sheer number of the papers that were reporting results which overestimated performance though was quite a shock!

I think from now on I am going to be even more rigorous about my results as well as those of the papers I review/edit!

A new dimension

I am intrigued by a new development: Springer has started a new series of books called Science and Fiction. This series contains sci-fi books written by scientists and writers of hard sci-fi which contain apart from the story itself, a section about the Science in the book. That is not all, the series has books that have a critical commentary on sci-fi and its interaction with modern Science, religion etc.  The series as the publisher’s site says, looks to uncover mutual influences, prompt fruitful interaction.

It is great to see a scientific publisher see the close link and interaction that human imagination creates between sci-fi of today and the Science of tomorrow.
It will be an interesting experiment and one that I hope will be successful.

I also wonder when those from the so-called literary establishment will see the same connection and give sci-fi its rightful place in the pantheon of serious literature.

CLEO 2015: a great few days!

While the Californian weather was chillier than expected the conference and people were as warm as ever.

I spent last week at CLEO 2015 in San Jose and had a marvellous time. Ruminating on the conference these were the highlights for me:

The plenary sessions included talks by Nobel Prize winners like Shuji Nakamura who helped solve the issues with blue-green LED/laser. One plenary in particular really caught my fancy: “Light’s twist” by Miles Padgett of University of Glasgow. Some of the things he talked about : the orbital angular momentum of light having helical phase fronts which are not be confused with circularly polarised light were fascinating. The fact that unlike the linear Doppler effect, orbital angular momentum would impart the same frequency shift irrespective of the frequency of the light wave was new to me, but when you think about it makes perfect sense. Perhaps the most thought provoking idea was that it is transverse boundary conditions/limitations on the extent of the light beam that lead to the beams such as Airy and Bessel beams, and a waveguide per se is not required. I need to go away and do a lot of reading, but I am excited!

In the “Modes in Fiber” session the talks covered large mode area fiber designs, as well as fabrication, and went on to some very interesting new ideas on quantum walks in multi core fibers. Large mode area fibers, as a member of the audience pointed out is not a new born field and there are several designs out there. So what makes a design worthy of attention? I think one of the authors answered this very well in his presentation, SM2L.2, when Deepak Jain spoke of the three factors that are key:

  • the metric used to decide what effective single moded operation
  • loss of the fundamental mode
  • the effective radius or area at which bend loss becomes large

This discussion particularly interested me because it is this sort of perspective setting that is so important for good research. At times one can get lost in the virtual forest of journal and conference papers each of which announce a slightly (or hugely) better performance. Yet what is the process for determining which design is really best and will perhaps become the industry standard? This is where conferences like CLEO that bring members of the community together can help find the answers or set people on the path!

Undoubtedly the most exciting talk of the session was SM2L.4 by Peter Mosley from Bath. He showed some exciting simulation and experimental results for multicore fibers, whose propagation constant differences were reconstructed by a Markov chain Monte Carlo simulation, a statistical approach. The striking thing was the difference between the classical behavior one might see (when a particle moves through an array with equal probability of moving left or right) and the non-classical behavior they demonstrated for a photon between coupled.

To me the highlight of Tuesday was the Women in Photonics Lunch that had two very high profile speakers: Prof. Michal Lipson of Cornell University and Dr. Hong Liu, principle engineer at Google Technical Infrastructure. These ladies gave very frank and honest insights into their career paths, the challenges they have faced specific to them being female and their advice for women in general.

When Michal said that people at times assume she works for Alex Gaeta, her husband and also a professor at Cornell, but never the other way round, it produced a wave of a laughter and nods of recognition at what so many women face: being talked over at meetings, being mistaken for the secretary etc. The sub-text or unspoken messages that women are given, of their careers being secondary to their male partner’s or colleagues were all realities that many present in the room could empathise with and perhaps you can too as you read it.

Their advice which works for both women and men contained some real nuggets. For example, “don’t put yourself down because the people around you do that to you”. This action of not internalizing the negative messages from those around us sounds very simple but can be very profound. They also advised everyone to set a high personal standard for oneself. Achieving to a high standard then means we feel more confident and feel we belong and deserve the success that we will hopefully achieve!

I cant end the post without talking a little bit about the great talk by Ayman Abouraddy from CREOL, Florida, who gave an invited talk Wednesday morning. He discussed in a very simple and engaging manner the challenges with making multimaterial chalcogenide fibers. He then went on to explain how using polymers in the process his group had overcome these challenges to fabricate  large index difference, small diameter, robust fibers with low bend loss. It wasn’t that the Science being explained was necessarily completely new to me, but a good review of the field coupled with very accessible explanations of the challenges and their solutions was valuable. A 30 minute talk allowed me to walk away feeling I have a good handle on the latest on the field of mid IR fibers. So time well spent!

Now that I am back in London, I am hitting the papers hard and hope to use my time at CLEO well, and planning for next year’s CLEO.

Conferencing and making conferences

Last month I breathed a huge sigh of relief, gratitude and immense pride after the successful completion of OWTNM 2015. The OWTNM 2015 was the 23rd Optical Wave and Waveguide Theory and Numerical Modeling Workshop. Here is a video from the conference:

While this was my first experience of making a conference happen, I learned so much, I am off now to CLEO to teach a short course on Finite Element method. I am so very glad that I will be mostly attending and not responsible for more than my short course and after that my own person!

I wanted however to share some of my learnings from OWTNM here.

For those of you organising (or thinking of) their first conference these tips might come in handy!

1. Dates: make sure you get the dates that don’t clash with another premier event of the same nature. That way you don’t compete with other conferences.

2. Venue: a city that has strong tourism appeal, easy flight connections and travel ease will invariable attract more people. Though big cities can be expensive, they are easier to get to, find hotels of all budgets and there are things for people to do in the leisure hours they have. Apart from choosing the city, the actual venue should be easy to reach by public  transport and preferably not in the wilderness. Disabled access, enough toilets, some social space for delegates to sit and relax, wi-fi access make things pleasant.

3. People: perhaps the most important thing of all! You will need the right people for each task. For local committee and reviewers you may need senior academics. Some of these will only review papers, some will only give you contacts (with distinguished speakers you want to invite for example).They may not have time to do the running around, so be realistic in your expectations of them.

You will need people to do the nitty gritty work; making the conference programme, book of abstracts etc. These have to be people who you can rely on to do a good job on time. they will tend not to be super senior.

Advisors: again probably senior people who have organised several conferences and from their experience can help you a lot with timely and useful advice. the previous year’s organisers are good potential advisors too. Someone who had organised an event in your institution is good to speak with aswell: they know how to deal with the challenges specific to your institution.

The heavylifters: no (not counting the very expensive and professionally managed, like CLOE) conference is possible with out the sincere and dedicated work from an army of student volunteers. These young people, mostly post-grads, PhD students, do a lot of the running around. They can come up with the most creative ideas, solutions to problems and exciting inputs. Remember though that they are not experienced in this so can make mistakes. Be prepared to supervise and also be calm and listen!

The administrative staff! you will need to work with finance, catering, IT, security and such services. All these individuals will have an impact on the conference but for most it is not their primary concern. So you must be sensible in dealing with colleagues from these services: make sure you communicate clearly, ask for things in advance and remind them as needed.

4. Communication: a good website is a must for a successful conference. Getting people to learn about the conference, giving them information about paper submission, acceptance, registration, visas, accommodation, venue etc… all this determines how many people attend and how much they enjoy the event. Make sure your website is updated constantly, and emails are answered promptly. An easy to navigate, attractive site is always better than an eyesore!

Communication is important also within the team . You need to make sure people know what is expected of them. That you know what they expect from you! Remember to thank people and acknowledge their efforts, their contributions.

5. Finance and sponsors: you need to start with this almost as soon as you know you will host the event. Ask previous organisers for sponsors who gave support. Talk to all the companies in the field, professional bodies, publishers. Call people! Sometimes you will have to call them again and again. It is harder to say no to someone verbally than in an impersonal email. So call! You will need conference information to sell the event to them: Highlights from the previous year, and what you expect will happen this year, the benefit to the company. The website is very handy for this. That is why keeping it updated is an enormous help in attracting sponsors.

6. Flexibility and planning : somethings will go wrong despite your best efforts. Try and keep some slack in the plans you make. Above all you need to stay calm, rational and informed to make the best decisions at a time of crisis. Make sure you have a list of tasks that need to be completed, and by when, what their priority is. This master plan should be updated regularly and will help you stay on track.

Delegate: don’t try and do every thing yourself. You have picked a team that you trust, now show confidence in them!

For now that is all I can think if! Don’t hesitate to send in your comments and thoughts.

This is part of the wonderful team of students who made OWTNM  2015 possible.DSC03777

PhD studentships available!

The School has announced a few PhD studentships and I am looking for some good students whose application I would be happy to support. Please contact me if interested. Some details are given below:

School is inviting applications for 6 full-time, three-year doctoral studentships for 2015/16 entry. Three of the studentships are funded by The George Daniels’ Educational Trust ; the other three are funded by the School.
The six studentships will be split equally across Computer Science (2 studentships), Mathematics (2 studentships), and Engineering (2 studentships).

What is offered
A doctoral studentship provides:
• An annual bursary (£16,000 in 2015/16);
• A full tuition fee waiver for UK and EU students. Applications are welcome from overseas applicants but the difference between overseas and UK fee must be covered by the applicant or by the supervisor/Research Centre (with prior agreement)

Successful applicants will be expected to provide 3 hours per week support for teaching in the School. Continuation of the studentship after the first year is subject to confirmation of satisfactory progress.

Applications are sought from exceptional UK, EU and international graduates and will be awarded on the basis of outstanding academic achievement and the potential to produce cutting edge-research.
• Applicants must hold at least a 2.1 honours degree or merit level Masters degree in a relevant subject (or international equivalent)
• Applicants whose first language is not English must have achieved at least 6.5 in IELTS or a recognised equivalent
• Applicants must not be currently registered as a doctoral student at City University London or any other academic institution

How to apply
Application deadline: 25th May 2015.
Prospective applicants are strongly advised to discuss their application in advance with a potential supervisor in the School in order to determine whether they can offer supervision in their chosen research area.

Applications must consist of the following:
• A completed Research Degree application form
• A 3 page research proposal. This should include (a) your research question(s), (b) background literature and motivation for the research and (c) methodology/work plan.
• Proof of academic qualifications, i.e. grade transcripts from your previous degree(s)
• Proof of English language proficiency if you do not speak English as your first language
• Two confidential references (one of which must be an academic reference)

The above documents should be compiled into a single document and submitted to by the 25th May 2015.

Selection Process.

1. Once all the applications are collected, Computer Science, Mathematics and Engineering should short list 4 applicants each.
2. The shortlisting panel for all areas will be led by: Computer Science: Prof Jo Wood; Mathematics: Prof Andreas Fring; Engineering: Prof Andreas Kappos
3. STRs should liaise with the above to assist them in the process
4. There will be a School panel to finalise the selection of PhD students on Wed 3rd of June 2015.

By artiagrawal Posted in General

Leadership lessons from VCs

Many of us dream of going right to the top: leading our institutions. Each year we see hundreds of students graduate and their dreams are as varied as they are. The kind organisations they join and which some of them will lead fit a very wide spectrum.

For academics who stay in the world of research and teaching the spectrum is narrower though not as one dimensional as some might think. There is need in this world too for excellent leadership, vision and a little bit of magic.

Firstly in my view universities are not businesses and their stakeholders more varied than any business: students, staff, research councils, charities, companies who commission projects, and most importantly society at large. We may be able to measure citation rates of papers, or construct impact studies of some of our research, even look at average earnings of our graduates. But there is no real measure to what universities contribute to the discourse of a society.

Yet when a university Vice Chancellor (VCs) is appointed he/she has to answer not only to the metrics and un-measurables from above, but also the very business like numbers of operating costs, profit, surpluses, and so on.

More and more VCs are like business leaders because the pressures imposed by governments to make universities more financially self-sufficient, force universities to behave like businesses (and not universities).

Is that good or bad?

Hard to say. But certainly there are some very game individuals who are doing their best running their unis. A very interesting article in Times Higher Education gives some lessons from 5 VCs.

My favourite tips from these were:

  1. When implementing strategy: understand how the institution works: politics and psychology of the organisation
  2. When going from a place to a new one as VC/leader, learn about it. Talk to as many people from as wide a range as possible
  3. Put the right people in right place
  4. Think on how to communicate decisions as much as decisions themselves

Now all I have to do is get a position as a VC and I can start implementing these on the grand scale. Till then perhaps in my smaller world trying out these things may help develop the leader in me!

The business of being busy

Very often when you try and arrange a meeting with an academic colleague the first available date seems to be more than a month in the future. Everyone is super busy, buried under mountains of marking, preparing for lectures, admin duties, writing grant proposals, vivas, other meetings and rushing about between conferences. Summer seems to offer no letup even though teaching is mercifully in a hiatus for some time. All the things one cannot manage during term get shoved into the summer. As though one can binge research in 2-3 months what one should be doing over an entire twelvemonth!
But such is academic life.

I don’t think this is great. I think we should have time to think and ponder, for our creativity to really flow. For both our research and our teaching.

There is a deeper issue here: Do we bear the badge of busyness with too much pride?

It seems to me that for some people the dashing about while juggling the many things they have to do gives them a sense of importance, perhaps a self affirmation. If we don’t have something to do every minute of the day we feel at a lose end. We need to radiate busyness with matters of global importance or we feel insecure about our place in the order of things.

But is it really cool that we never have enough time for leisure? That we can never slow down, or have a few minutes each day to think or just let our minds be blessedly blank of the endless to-do list?

I find myself doing this at times and I want to stop myself going too far down that road. I want to have time to smell the flowers as much as I want to solve the next global crisis.

Publishing a paper with simulation results

Dealing with tons of papers on simulation (or containing some simulation) results, as reviewer, editor (of IEEE Photonics Journal and JEOS RP) and conference chair of OWTNM 2015, I thought I’d point out a few (hopefully) useful things that I’ve picked up.

Some pointers are general and applicable to any paper, and others more specific to simulation related papers.


– when suggesting potential reviewers for your manuscript, make sure the email addresses of these people are correctly entered! I cannot tell you how frustrating it is as an editor to find this information is inaccurate and preferred reviewers cannot be contacted.

– do not suggest reviewers from your own research group or institution, to avoid a potential conflict of interest

– make sure your own inbox doesn’t bounce back emails from the editor!

Simulation related:

– for papers that present new algorithms and methods, it is imperative to convince  reviewers that the method works. The best way to do so is to show test results for the method against problems for which analytical or well known solutions exist. The more standardised and well accepted the test problem, the more credibility it lends your method. Benchmarking against results from other well cited results can also be quite helpful. Do this before applying the method to a new structure and presenting those results.

–  show tolerance and stability behaviour: since the method will have a number of parameters it is a good idea to show how error/accuracy varies as a function of these variables. The stability behaviour of the method against parameters can indicate the robustness of the method.

– if there are limitations to the method, it may be worth discussing these sometimes. It can help to define the applicability of the method.

These all constitute useful information for reviewers and editors when making decision to accept a manuscript: how sound the manuscript is technically, how useful will it be to readers, how widely it will be read and how well presented it is?

Benchmarking: test drive your code/software

Hello all!

It has been a long time since I blogged. Been extremely busy with the organisation of the OWTNM 2015. The paper submission just closed. The good news is that this year OWTNM will feature a training session with Lumerical (free to attendees) and also a free Women in Optics workshop (with lunch). The technical papers and sessions will be up on the site soon. Do attend if you can!

But now on to a blogpost! Why benchmarking and what is it?

Would you buy a car without a thorough test drive?

If the answer is no, then read on…

First the why benchmark: to make best use of your simulation software/code.
Benchmarking allows you to:
– generate results that are reliable and repeatable, giving referees (and you) confidence in these. When you include some benchmark results in a paper, for example, reviewers are more likely to trust your findings. Also other authors when they want to use the same approach (and perhaps cite your work) can repeat your work and obtain the same results, so they know they are on the right track in using the technique/structure etc. This enables your results to be used and cited more widely.

learn the sweet spots and limits of the software/code: you would not expect a car to fly like an aeroplane or a bicycle to be ridden as fast as a bullet train. Similarly the software/code will have an optimal performance for the input parameters. It is worth knowing first of all for which problems the software can be used (time domain problems for example need a method belonging to either FDTD/FETD/Time BPM class, and a simple mode solver may not work). Then having identified the nature of the problem and the appropriate method/software for it, comes the choice of values of parameters.

The idea is to identify the error dependence of the results on the parameter values. How large a time step, or propagation step can you take and the error to be acceptable? What index difference (in the structure) can the software handle accurately? How many grid/mesh points are needed to represent the structure with sufficient accuracy and still be fast enough?

Benchmarking helps learn:
Can you trust the results you get (for a new as yet not well understood structure)? Are these parameter values too large/small/just right? What sort of error should you expect?

These are the sort of questions worth answering before you embark on simulating a new structure. Which brings me to the what is benchmarking and how to do it…

Benchmarking in my opinion is simply matching results with your software/code for a known problem to test its accuracy.

How should you benchmark:
– As a rule of thumb, pick up a problem/structure for which results are known well, if possible analytical solutions are available. (you would ofcourse have made sure the problem you are trying to solve and the solver/software you are using for the purpose are right for each other!)
– Then try and repeat the well known results for the parameter values published. Do these match well?
– If the first two steps make you happy then this third is worth implementing. Now fix all input parameters except one. Change values of this parameter and plot the results as a function of the parameter, tabulate them. This should show you the error as function of the parameter. Do this for all the key parameters.
This step is critical in identifying what parameter values you can use and still get results that you can trust.

Remember, with fabrication, tolerances are important. So experimental colleagues, reviewers, grant funders, manufacturers all want to know what happens to the performance if the parameter value changes by say 5%.
You need to know the answer to that one, and also to know how much error is present. If the error in the simulations is 5% then the tolerance has to be greater than 5% for the results to be useful!

Benchmarking can seem like a laborious and boring task. But it is very much worth it. Do it properly once and then you can really use the software to the max!

An early Christmas present

The past month has been very hectic and filled with submissions, marking, student presentations etc…

Now that Christmas is almost upon us I wanted to relfect on the year a little, given the few minutes of breathing space!

Perhaps the biggest achievement or exciting journey that has begun for me is the launch of the Women in Photonics (WiP) initiative of the IEEE Photonics Society. As the Asosciate Vice President of WiP my job is to get more women into and onwards in Photonics. This may not directly have anything to do with my career, but I relish the opportunity to contribute something positive and help make those changes happen that I believe are needed. It is the first step in a long process which will I am sure throw up challenges and frustrations. But along the way I hope there will be real progress and when I am 65 I can look back on this with some satisfaction and say “I was part of this change”.

From a technical point of view satisfaction has come in working with an experimental group. We simulated the optical properties of solar cells, whilst my collaborators fabricated and characterized these. There is so much joy in watching the numerical results closely explain the measured data! Our joint paper is now published and available.

What lies ahead:
The biggest thing on the horizon is the OWTNM 2015 which I am chairing and organising. Getting to grips with making an international conference happen is huge: somethings are incredibly simple and common sense (no matter how tough it all looks) and others are fiddly and cumbersome (no matter how easy they may appear). It is only after the event is over will I know how it really went.

There are ofcourse many other things to look forward to. I will be giving a short course at CLEO 2015 again. There is the collaborative work with Aston university on spiral waveguides in Lithium Niobate.
And much more..

I hope you all have a lovely Christmas and fabulous 2015.